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semiconductive
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hemicellulose solvents, glycerine and alkali react?
I've been trying to dissolve hemi-cellulose from wood. I'm studying solvents to learn about wood preservation in musical instruments. The wood used
in Stradavarius violins, for example, are famous for sound known to be caused (partially) by wood preservatives that remove certain wood sugars. I
don't expect to create a Stradivarius, but I'd like to understand the chemistry better.
If you don't need background information on wood sugar and solvent experiments ... then skip down to where I've marked questions (Q1-Q4) at the left
hand side of the text.
You can always come back and read my long explanation of existing experiments later, if the the questions don't make sense to you.
I found (online) a large number of studies about separation of wood/plant cellulose from lignin and hemi-cellulose. Those are the three major
polymers found in wood. The studies I found are mostly interested in producing bio-fuels and completely destroying the plant material; however, I
only need to remove hemi-cellulose. That's the weak part of wood that dampens sound and makes wood prone to rot and fungus. I don't need to
decompose all the wood nor do it quickly.
But ... I'm still having trouble even verifying experimental trends discovered in the bio-fuels studies; because bio fuel studies don't need intact
wood during or after processing, but I do.
I'd appreciate some advice about designing experiments to accurately estimate quantities of wood sugars dissolved when the wood is not ground up
before the experiment. eg: I'm only interested in chemical attacks on solid wood which minimally harm lignin and cellulose.
The bio-fuel studies' chemical consensus is that strong acids hydrolyze the lignins and break down cellulose in wood quickly but alkalis don't; so
I'm staying away from acid solvents. Nitrogen containing compounds also tend to slowly attack lignin ... so concentrated ammonia or nitrate salts are
a last resort. Strong bases are generally recommended for dissolving hemi-cellulose.
The common, effective, and well known bases that attack hemi-cellulose are sodium hydroxide, calcium hydroxide, and postassium hydroxide. Almost
always, the biofuel studies dissolve these strong bases in water at elevated temperatures and use them as a solvent for wood sugars. The experiments
soak plant material from hours to a couple of days. The only exception is low-cost calcium hydroxide, which is more often used at lower temperatures
because of it's negative solubility coefficient in hotter water. CaOH studies, therefore, sometimes extend over weeks in cold water.
However, the results of all effective and strong hydroxides in water appear to have one drawback ... they don't dissolve xylose ... Xylose is a
significant component of hemi-cellulose. The only studies that notice this single xylose/sugar failure, experimented with DMSO and boric acid salts
to remove the stubborn xylose residues.
My goal is to find which solvents can selectively remove all the sugars in hemi-cellulose from wood while degrading the lignin and cellulose very
little. EG: without completely destroying the wood structure and integrity.
Almost all bio-fuel studies used only one solvent, and few to none of them experimented with combinations. For example, none of them tried to use
both alcohol and an alkali at the same time (mixed together).
The problem I'm coming across is that the solvents change their characteristics with time even when only one is used, and obviously multiple solvents
interact with each other.
For example, calcium hydroxide in water is a good at attacking and breaking down hemi-cellulose polymers. However, the digested material
precipitates to the bottom of an Erlenmeyer flask full of solvent after about 6 hours of being in solution. The dissolved solids don't stay in
solution (See first photo). ( I suppose that means an unknown amount of the wood sugars are also re-depositing inside the wood over time, as well. )
Alkalai in alcohol (eg: in methanol) makes a colloidal suspension that is indefinitely stable when it's just alcohol involved. So, it seems
preferable to dissolve calcium hydroxide in an alcohol or alcohol + DMSO ; to reduce precipitation while increasing suguar solubility.
From a preliminary experiment I tried; I can qualitatively see strong wood colored solvent even after two days; so I think more material stays in
solution with either alkalaine Glycerine+methanol or DMSO+methanol -- than with alkaline water.
 
But I'm having a problems quantifying (weighing) results. DMSO and Glycerol both adhere to wood and don't evaporate on drying.
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Q1: I have unknown ratios of DMSO and Glycerine in both the precipitate and the original wood when trying to dissolve hemicellulose.
How can I design an experiment to quantitatively figure out which solvent(s) remove more wood sugars? I mean, I have thought of pre-wetting the wood
with a solvent -- immediately drying the wood sample again and weighing it to get a tare weight of how much solvent sticks to wood even after drying.
I would be hoping the solvent doesn't have enough time to remove significant hemi-cellulose... but I'm not sure if the mass gain at the start of the
experiment (a tare weight increase) would accurately estimate the amount of solvent at the end of the experiment; eg: after soaking for several days
and then re-drying.
Is there a better way to determine how much solvent remains in the dry wood at the end of the experiment?
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The second issue I'm having is with side reactions.. When I added caclium hydroxide to glycerol, the literature online suggests that about 1.5% w/w
of the hydroxide ought to dissolve. No mention of side reactions is made.
When I dissolved 100mg of ms' wages (TM) pickeling lime (CaOH) in 9g of U.S.P glycerine; the quick lime goes into solution slowly and with some
trouble. I was never able to get 200mg of q-lime to completely dissolve in 9g of glycerol. But, I found that if I partially-dissolve 100mg
quick-lime in a little bit of methanol (1g), before dissolving it in glycerol (9g) ... the lime cleanly disappears into the glycerol very quickly.
The glycerine rapidly turns pale/light yellow. So, the online data I found stating that only 1.5% or less w/w q-lime to glycerol is soluble seems
reasonable.
However with time, the glycerol darkened and goo fell to the vial's bottom while being warmed at 70C. At first I thought the darkening and goo was
just because of oxygen and heat ruining some of the glycerol. So I tried again with a cap on the top of the vial to exclude as much oxygen as
possible. I left the vial overnight at room temperature ... and the color was still light yellow in the morning. The two vials can be seen in the
right-most picture, above. The dark colored two dram vial was cooked at 70C on the hotplate (to the left). The light yellow two dram vial was never
heated.
Note: The Erlenmeyer flasks contain earlier experiments with mixed solvents. The front most flask contained glycerol and methanol mixed with q-lime.
-------------------------
Q2: What temperatures can be expected to ruin/oxidize glycerol when a strong base is present?
-------------------------
Before heating the new yellow vial to 70C, I examined it closely. I noticed a semi-transparent precipitate along the crease of the vial on the
bottom. When I turned the vial sideways; the precipitate floated off as a ring in one piece (like it was polymerized), and eventually broke into four
arcs when shaken. (Magnified Picture below). Obviously some kind of chemical reaction happened over-night even at room temperature. None of the
studies mentioned how the glycerine degraded as they didn't use it with bases. I am not sure if the polymerization reaction is typical for
glycerine and strong bases or not; and I'm not sure when Glycerol is degraded by heat.
So, it seems like the most promising solvents (alcohols and calcium hydroxide) have side reactions causing precipitation. I'm familiar with ester
formation, but I don't know what alkali's/bases do to alcohols or how temperature affects the reaction. I am not finding helpful literature through
google either ... any help appreciated.
The uncooked glycerol solution is still yellow, so I think the vast majority of q-lime must still be in solution. (eg: More than half.) Glycerol has
three -OH radicals, but the carbon the -OH's are bonded to have different surrounding carbon bonds; I think the nature of the bonds changes the
chemical reactivity of the -OH radicals so they aren't all equal. Could the precipitate/polymer be an effect of which -OH the q-lime attacks? eg: a
fixed percentage of chemical reactions lead to polymerization?
-------------------
Q3: Is a probable reason and stoichiometery for glycerol precipitation/polymerization by hydroxides known? Can I add a specific extra amount of
strong base to glycerol to compensate for the hydroxide loss to precepitation? ... OR will glycerol continue to precipitate/polymerize with time and
remove hydroxide [eg:CaOH] so that compensation is hopeless?
-------------------
-------------------
Q4: Boric acid is very helpful in dissolving xylose as an alternative to DMSO. However, calcium borate (gerstly borate) appears to be insoluble in
alcohol or glycerine. Does anyone know of basic organic solvents that might be able to keep boric acid salts in solution?
--------------------
I have thought of using inorganic Magnesium hydroxide in place of calcium hydroxide. But there doesn't seem to be any data on the solubility of
magnesium Borate in alcohol --- I'm not even sure the compound can be formed. I tried mixing magnesium carbonate with Boric acid, but didn't see many
bubbles... so it might not form. If magnesium hydroxide will dissolve in glycerol along with boric acid and not react --- that might be worth trying
as a solvent; but I can't find data on Mg[OH]2 -- showing Glycerine solubility. if Mg[OH]2 won't dissolve at all, then making Mg[OH]2 is a waste of
time (I don't have it on hand) Anyone have thoughts, data, or suggestions?
I have knowledge about percentages of various sugars in different species of wood. Just ask if you have questions. The experiments I am trying are
with Balsa (a hardwood!!!/angiosperm) and rot-resistant Western Redcedar (a softwood / gymnosperm.)
These wood species are chemically representative of the wood sugar profiles found in other kinds of wood used to make musical instruments.
[Edited on 16-3-2018 by semiconductive]
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semiconductive
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One small note, Mrs. Wages pickling lime is completely slaked lime ( CaOH), with no CaO in it. So, where I mentioned quick lime; I'm sure the
chemical is actually slaked with water, and not directly attacking the glycerine as CaO. Sorry for any confustion I caused.
I came across some experimentation on sciencemadness with calcium hydroxide and sugars, which will parallel what should happen with wood sugars.
Interesting that they experimented with glycerol as well....
http://www.sciencemadness.org/talk/viewthread.php?tid=9811
https://pubs.acs.org/doi/abs/10.1021/j150118a005
I also just found some patent literature (old) about alcohols condensing from lower weight to higher, in the presence of calcium hydroxide (1949).
https://patents.google.com/patent/US2645667
I don't have any of the standard catalysts present... but perhaps glycerol is condensing to a higher molecular weight alcohol?
[Edited on 20-3-2018 by semiconductive]
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NEMO-Chemistry
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Have you looked at how they extract Birch sugar? (Xylitol).
A complete guess but getting a precipitation dosnt mean you havnt removed everything. Its not much use but I can tell you one thing from a recent
experiment making charcoal.
I got sick of the foul gunge in the can making charcoal, so i started to use only beach Driftwood that was white and light. When you turn it into
charcoal you get zero tar. If you look at a section under a microscope you see the wood is full of holes.
So may i suggest you try Sodium Chloride and maybe something like sodium Carbonate. Might take a while but i can say that driftwood dosnt seem to have
much left in it after its been in the sea a while.
My assumption is the PH and osmotic difference draws out anything soluble, no idea if its going to take any of what you want to leave though. Very
interesting experiment, Xylitol is expensive so i am guessing not straight forward to target.
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semiconductive
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I hadn't looked up birch sugar yet. Now that I have....
Xylitol is hydrolyzed xylose, I think. Eg: an alcohol product caused by breaking a sugar bond and replacing it with part of water ( -OH ). Pretty
much hydrolyzing means a manufacturer used an acid process to extract it. Bases are very slow to hydrolyze anything, so it leaves the wood intact and
won't produce much alcohol. (xylitol). Bases should only dissolve and re-deposit xylose, slowly.
I did a quick google search, and a cursory look at articles suggests an acid decomposition really is the normal way xylitol is made.
https://xylitol.org/about-xylitol/corn-xylitol-vs-birch-xyli...
Since the sweetner companies are only interested in a powdered product, they don't care if they destroy the wood (or bark) it comes from. So, that's
why they use acid. Note: using acid also has a side effect of hydrolyzing many other sugars in the wood, so that the xylitol's sold on the market has
to be fairly impure. The difference in solubility between various hexoses and pentoses is likely very small. So, re-crystallization isn't going to
do a very good job of purifying the sugars from each other. The purity is going to depend heavily on the ratios of different wood sugars present
either in birch or corn cob.
I think you are closer to the right track with driftwood. Chemical analysis of Stradavarius samples suggests a brine was used of some kind. The
holes in driftwood, however, are also from parasitic worms that live in the ocean -- wood borers. Normal ocean water supports their life-cycle; but
once on the beach, the worms tend to die.
There are, however, archaeological finds of wood hundreds of years old preserved (and sometimes destroyed) by salt; now that you got me thinking in
that direction.
http://forestpathology.cfans.umn.edu/pdf/Dead_Sea_Wood.pdf
Your suggestion of using salt water is probably a good one; but there is also a point where too much of the wood has been digested by bacteria/fungus
if they grow in salt water. I assume that drift wood is not particularly strong compared to normal tree wood; eg: It's not particularly good for use
as lumber.
So, there is a certain probablility that perhaps salt, bactera or fungus can be used to remove/eat out the food product -- xylose -- while leaving
lignin and cellulose intact. it's just a matter of selecting the right salt environment for the particular bacteria involved to minimize damage to
lignin and cellulose.
In either event; I still have to figure out a way to measure how much sugar is actually extracted from the wood (mass) vs. what mass is accidentally
added (salt residue.../DMSO/glycerine... etc.)
I've only been focusing on alcohols as a solvent because they are reported to dissolve more sugar (of any kind) than water per mass. esp. when sugar
is NOT hydrolyzed. (eg: not acidified). In general, many studies use methanol or ethanol to extract "free"/non-polymerized sugars before starting
an investigation into chemicals which digest polymerized sugars.
There are some processes that digest wood using alcohol ... eg: ALCELL, etc. but the studies interestingly point out that it's actually fairly
difficult to get alcohol to destroy lignin without adding a chloride salt and water. (CaCl). The stronger the alcohol solution, the less lignin
dissolves in it.
However .... I just picked up the soaked balsa samples from a few days ago. The one soaked in MeOH + glycerol, was soft and rubbery. The one soaked
in DMSO+MeOH was still rigid. Strong glycerol (a triol) might be dissolving something more than I want it to!!
My measurements show that of the four wood samples I soaked in the Erlenmeyer flasks, all of them shrank in cross section a little; but not all of
them reduced in mass. The dimensions called mils is 0.001 inch units. eg: the original balsa was bought as 1/2" x 1/2" square stock, which is 500x500
mills. The original wood actually measured 500x510 mils; an average of 505mils. After soaking, I measured the cross section on all four faces and
took a geometric average when reporting results. The "wet" weight is ignorable, that's just what the dripping sample weighed as methanol evaporated
off of it. It's not really accurate.
------------------------------------------------------------------------------
Experiment I: Baseline Balsa in methanol.
444mg Balsa, 33.5%= 149mg hemicellulose
30mg CaOH
30mL methanol
wetweight: 2.084g , dry weight: 419mg 1 day. -25mg xsec=483 mils -4.4%
------------------------------------------------------------------------------
Experiment II: Baseline Balsa in water.
425mg Balsa (heated dry). * 33.5%=~142mg hemicellulose
30mg CaOH
~30mL water.
wet weight: ?2.2? Dry weight: 392mg 1 day. -33mg xsec=472 mils -6.5%
425-392=33mg loss
------------------------------------------------------------------------------
Experiment II: Glycerol enhancement
463mg Balsa : 33.5%=~155mg hemicellulose
30mg CaOH 30mL methanol
unknown glycerol; >2 grams
Wet weight: 1.9g? Dry weight: 716mg 2 days. +253mg xsec=467 mils -7.5%
------------------------------------------------------------------------------
Experiment III: DMSO enhancement
450mg Balsa 33.5%=~151mg hemicellulose
30mg CaOH 30mL methanol 250mg DMSO 99%
Wet weight 2.420g: Dry weight: 446mg 1 day. -4mg xsec=492 mills -2.5%
[Edited on 20-3-2018 by semiconductive]
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NEMO-Chemistry
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Hi.
I agree that it is likely they use acid for speed, this does not stop you using a base. You are not after speed but removal, so if Birch sweetener is
removed with an acid for speed, try a base but a weak one.
Regarding the drift wood, i am really sorry i didnt give enough detail. I wasnt talking about wood that has been in the water for years or even
months.
Where I live Forestry is the main industry, it is also on the coast and we get alot of driftwood. It drops in one side of the bay and we pick it up on
the other. This is maybe a few weeks tops, under the scope you would spot worm holes.
These are not worm holes, there is little difference apart from some widening, between what you see with the sugars and oils and spaces in wood, one
has the 'junk' in it the other dosnt. Alot of things are indeed removed as the weight difference is significant.
But strength wise there is little loss as long as it hasnt been in too long. Methanol is from wood, it would make sense that it dosnt destroy too much
so would make a good carrier. After all Methanol is also called wood alcohol.
I am not surprised Brine was used, it would have to be fairly low tech for the time. Methanol would have been about and Brine used alot with Nitrates.
I think the technique is one of time, how high the PH and how long the soak. Funny you mention salt remaining in the wood, I also expected this but
found no strong colour emission for sodium.
Do you know the actual wood used? Its ok working with balsa, but its isnt giving you realistic results. Use the wood that is used in the instrument,
the make up of sugars and chemicals differs widely from tree species to tree species.
Think Pine and resin, Birch and aspirin or Those trees like Eucalyptus with a strong oil, my point is trees transport these around there systems and
not all trees have the same make up.
My concern would be you finding a decent way for one wood that simply dosnt work on another. When instruments of this quality are made, you are also
paying for time and skill, so look again at how it is done quickly and if it can be done with a slower method. Like the Xylitol, then choose the slow
way.
His instruments fetch money because time has proved them the best, but way back when i suspect it was more about how long they took to craft that cost
the money.
It is an intriguing experiment, may i suggest you cut 2-3mm cross sections in round wood (like branches). Look at them under the scope then soak for
various lengths in true brine. Then keep looking at the section under the scope.
My other gut feeling is brine and then heat in the form of steam. Drive out the water and salts under pressure by boiling off the Brine solution with
a steam cupboard used for bending wood, make sure its really hot first. Maybe start at 15 mins steam treat after the brine upto around 50 mins, past
that i dont think you gain much.
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NEMO-Chemistry
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One last thought, have you looked into enzymes like hemicellulase?
Not sure if any of these help, but maybe they will spark an idea for you.
http://sci-hub.tw/10.1094/CCHEM.1997.74.2.176
Note the above address is scihub, however look where the direct comes from, surprising!
http://www.aaccnet.org/publications/cc/1997/March/Pages/74_2...
I am sure you have read this but...
https://en.wikipedia.org/wiki/Stradivarius
Note these bits
Some research points to wood preservatives used in that day as contributing to the resonant qualities. Joseph Nagyvary[46][47] reveals that he has
always held the belief that there are a wide range of chemicals that will improve the violin's sound. In a 2009 study co-authored with Renald
Guillemette and Clifford Spiegelman, Nagyvary obtained shavings from a Stradivarius violin and examined them, and analysis indicated they contained
"borax, fluorides, chromium and iron salts."[48] He also found that the wood had decayed a little, to the extent that the filter plates in the pores
between the wood's component tracheids had rotted away, perhaps while the wood was stored in or under water in the Venice lagoon before Stradivarius
used it.
Also the mention of the little ice age of the time and dense wood.
[Edited on 20-3-2018 by NEMO-Chemistry]
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Boffis
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I'm no expert on sugar/wood chemistry but I can see a few problems and misconceptions in your experimental outline.
1) you seem to be confusing "solvation" with "depolymerization". It looks like the alkali is acting to depolymerize the hemicellulose in preference to
cellulose (I presume this works and that you have references to this). However, the solvent is still water or alkohol etc.
2) I would have thought that you would need to acidify the Ca(OH)2 hydrolysed to liberate the sugars in a water or alcohol soluble form since many
sugars form sparingly soluble salts with alkaline earth hydroxides. These "salts" are used commercially in the refining of cane and beet sugar. So
could the lack of solvation of your hydrolysed sugars be due to the formation of these calcium sugar salts? These compounds are not very stable since
the sugars are very weak acid so short treatment with acetic acid for instance should liberate them. Commercially I think they use CO2 but this causes
CaCO3 precipitation which in your case I think would be undesirable. I am not sure to what extent glycerol or DMSO would help in this case, I would be
surprised if calcium sugar salts are particularly soluble in glycerol (no idea about DMSO).
Xylitol (a pentahydroxy alcohol) is not hydrolysed xylose (a pentose sugar like ribose). It is Xylan that is hydrolysed to xylose (amongst other
things), xylitol is the reduction product of xylose. Some Xylans also contain an aromatic residue such as 3-methoxy-4-hydroxycinnamic acid etc which
are also likely to form insoluble calcium salts.
Since you appear to be trying to preferentially strip out the xylan component I think that you need to look at low temperature hydrolysis with either
NaOH or Ca(OH)2 but if you use the latter you will probably need to wash with dilute acid and an alcohol. Remember most sugars are more soluble in
water than alcohol. I don't know about in DMSO or glycerol.
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NEMO-Chemistry
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Quote: Originally posted by Boffis  | I'm no expert on sugar/wood chemistry but I can see a few problems and misconceptions in your experimental outline.
1) you seem to be confusing "solvation" with "depolymerization". It looks like the alkali is acting to depolymerize the hemicellulose in preference to
cellulose (I presume this works and that you have references to this). However, the solvent is still water or alkohol etc.
2) I would have thought that you would need to acidify the Ca(OH)2 hydrolysed to liberate the sugars in a water or alcohol soluble form since many
sugars form sparingly soluble salts with alkaline earth hydroxides. These "salts" are used commercially in the refining of cane and beet sugar. So
could the lack of solvation of your hydrolysed sugars be due to the formation of these calcium sugar salts? These compounds are not very stable since
the sugars are very weak acid so short treatment with acetic acid for instance should liberate them. Commercially I think they use CO2 but this causes
CaCO3 precipitation which in your case I think would be undesirable. I am not sure to what extent glycerol or DMSO would help in this case, I would be
surprised if calcium sugar salts are particularly soluble in glycerol (no idea about DMSO).
Xylitol (a pentahydroxy alcohol) is not hydrolysed xylose (a pentose sugar like ribose). It is Xylan that is hydrolysed to xylose (amongst other
things), xylitol is the reduction product of xylose. Some Xylans also contain an aromatic residue such as 3-methoxy-4-hydroxycinnamic acid etc which
are also likely to form insoluble calcium salts.
Since you appear to be trying to preferentially strip out the xylan component I think that you need to look at low temperature hydrolysis with either
NaOH or Ca(OH)2 but if you use the latter you will probably need to wash with dilute acid and an alcohol. Remember most sugars are more soluble in
water than alcohol. I don't know about in DMSO or glycerol. |
A bit above my knowledge, but would this fit with Brine and the mention of Rome and water.... I expect 'fresh water'?.
All I can go on is knowing brine solution removes all the gunk, including the sugars and it makes a great charcoal. The other factor i read i dont
think your going to copy, when these instruments were made they made in a specific frame of history. The mini ice age and stunted dense trees.
I could be utterly off base, but salt water draws water out of wood. Sugar is water soluble, take out the water with brine and you should get the
sugars.
Unless something crops out i actually i know about i will shut up. I simply saw that your looking at getting rid of some of what causes the gunge in
charcoal making, I used a wood that did this. Might be no connection but the more I read about the guy the more i think all the varnish stuff etc is
myth.
I think he was just good at his job and had access to good materials, not on wiki it mentions a small amount of rot.....
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NEMO-Chemistry
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The other thing from question 1)
How do you quantify how much sugar is removed....
Look at the sugar and see if its a reducing one, titrate both the solvent after and a destroyed sample of wood and titrate.
Not sure what the tests are for non reducing sugars but there is sure to be some kind of titration or GC/MS method or even chromatography. For example
a sample of solvent with no sugar will have a known density, after you treat, then all you need to do is get the density for a known amount.
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Bert
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If you want to recreate the Stradivarius treatment, perhaps you should limit the chemical choices to those available at that period?
Biological activity to consume the undesirable wood components during an immersion in canal water (yech! Canal water was about like an open sewer, in
those days-), followed by preservative inorganic chemical treatments?
If you just want the same EFFECT, but quicker and surer/amenable to modern industrial control methods? And you already understand how this effect was
achieved?
Pressurized wood treatment with liquified gasses or chemicals born by such liquids should be faster than soaking to thoroughly permeate a plank.
Liquid CO2 or anhydrous ammonia treatments have been used by woodworkers for other effects, such as liquifying the lignin temporarily to allow complex
bending operations without steaming.
Steaming? How does a steam distillation affect a solid plank, or a similar treatment with alcohol vapor, produced either via heat or low pressure?
Soak the wood in your alcohol/other appropriate liquid solvents, plus any needed wood treatment chemicals, then pull a vacuum to extract the solvent
and whatever it can carry away? Repeat to rinse?
[Edited on 20-3-2018 by Bert]
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semiconductive
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I haven't looked at enzymes. I tried cellulase some 20years ago, trying to digest cellulose to see if it could be fermented to make cheap alcohol.
The enzyme was sold over the counter for RV's to break down toilet paper. I tried it with cotton, but the enzyme was so slow to break down cellulose
that I gave up. I followed the instructions but it was abysmally slow. Does anyone have experience with hemicellulase enzyme / success ? Would it
work in less than 30 days?
| Quote: |
I am sure you have read this but...
https://en.wikipedia.org/wiki/Stradivarius
Note these bits
Some research points to wood preservatives used in that day as contributing to the resonant qualities. Joseph Nagyvary[46][47] reveals that he has
always held the belief that there are a wide range of chemicals that will improve the violin's sound. In a 2009 study co-authored with Renald
Guillemette and Clifford Spiegelman, Nagyvary obtained shavings from a Stradivarius violin and examined them, and analysis indicated they contained
"borax, fluorides, chromium and iron salts."[48] He also found that the wood had decayed a little, to the extent that the filter plates in the pores
between the wood's component tracheids had rotted away, perhaps while the wood was stored in or under water in the Venice lagoon before Stradivarius
used it. |
I've read it. The boric acid is the part which I found most interesting, as that's known in modern experiments to be especially helpful in removing
hemicellulose. The fluorides were the other chemical that made me curious, but there's no obvious reason why fluorides would have used in wood
preservation. I don't think the particular chemicals used in a Stradivarius were all common at the time. It seems more likely that someone made a
mistake and substituted a similar looking chemical for another because it was cheap...
Also, the quality of sound for a violin develops over time. The Stradivarius would not have sounded the same as it does today for the first 15-20
years of use. By the time anyone realized it was a special violin ... I think the relationship between the final sound and the original chemistry was
already long lost.
I'm not really interested in re-producing a specific vioin, anyway. I'm just interested in small improvements to the wood. My first love is harps.
There are two notorious problems, however, in all wooden musical instruments. The first is moisture variation changing sound quality and ruining the
tuning, and the second is warping, cracking and rupture due to fungus and aging while under stress.
[Edited on 20-3-2018 by semiconductive]
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semiconductive
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| Quote: Originally posted by Boffis | I'm no expert on sugar/wood chemistry but I can see a few problems and misconceptions in your experimental outline.
1) you seem to be confusing "solvation" with "depolymerization". It looks like the alkali is acting to depolymerize the hemicellulose in preference to
cellulose (I presume this works and that you have references to this). However, the solvent is still water or alkohol etc.
|
I understood that a solvent was whatever liquid chemical is used to turn a solid into a dissolved liquid. Often chemistry texts will talk about
hydro-chloric acid "dissolving" aluminum. But, with your perspective -- water's the solvent, and the acid is chemically digesting the aluminum,
correct? So, I think it's just common practice to call everything in the liquid which is used to break down a solid as "solvent." ... but I agree,
the main purpose of the alkalai is to depolymerize the hemicellulose. There are, however, several references in the studies to the solubility of
alkali increasing with amount of dissolved sugars. In that case, they are not talking about a chemical change ... but of already-depolymerized sugars
affecting the amount of alkali that dissolves into water.
For example, I can dissolve more CaOH in water if I add either glycerol or sucrose or saccharose. Therefore, I left part of my comments vague
because I am not sure if the reverse effect (synergistic) also exists; eg: Given ONLY monomers of sugar; If alkali is present, will more monomers
dissolve in solution or not?
| Quote: |
2) I would have thought that you would need to acidify the Ca(OH)2 hydrolysed to liberate the sugars in a water or alcohol soluble form since many
sugars form sparingly soluble salts with alkaline earth hydroxides. These "salts" are used commercially in the refining of cane and beet sugar. So
could the lack of solvation of your hydrolysed sugars be due to the formation of these calcium sugar salts? |
Excellent question. I don't know.
| Quote: |
These compounds are not very stable since the sugars are very weak acid so short treatment with acetic acid for instance should liberate them.
Commercially I think they use CO2 but this causes CaCO3 precipitation which in your case I think would be undesirable. I am not sure to what extent
glycerol or DMSO would help in this case, I would be surprised if calcium sugar salts are particularly soluble in glycerol (no idea about DMSO).
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Calcium and Glycerol are rather curious. From previous experiments, I know that the maximum Mrs. Wages pickeling lime (CaOH, fine powder) that stays
in colloidal suspension is about 5mg / gram of Methanol. So, predictably ... when I made a suspension of 1g of pickeling lime in 30mL of MeOH, most
of it falls to the bottom in a matter of minutes.
If I attempt to dissolve more than 20mg of pickling lime / gram of glycerol; there is always a sticky mass that stays at the bottom of the vial that
doesn't dissolve even after a few days.
However, I just ran another experiment where I made a colloidal suspension of 1 gram of CaOH in methanol, and then added 2.505g of glycerol. My
intention was to find out when Glycerol starts turning dark as I raise the temperature from 40C to 70C. I expected a bunch of CaOH to stay on the
bottom, and the glycerol to become saturated with as much CaOH as possible.
To my surprise, all the CaOH is in Glycerol/methanol solution even after evaporating off most of the methanol. (I'm down to about 4g of solution,
from the initial ~35g). The color did not turn yellow, like it did before ... but is a milky white with greenish tinge.
| Quote: |
Xylitol (a pentahydroxy alcohol) is not hydrolysed xylose (a pentose sugar like ribose). It is Xylan that is hydrolysed to xylose (amongst other
things), xylitol is the reduction product of xylose. Some Xylans also contain an aromatic residue such as 3-methoxy-4-hydroxycinnamic acid etc which
are also likely to form insoluble calcium salts.
|
OK. That makes sense. I'll look into that more closely.
| Quote: |
Since you appear to be trying to preferentially strip out the xylan component I think that you need to look at low temperature hydrolysis with either
NaOH or Ca(OH)2 but if you use the latter you will probably need to wash with dilute acid and an alcohol. Remember most sugars are more soluble in
water than alcohol. I don't know about in DMSO or glycerol. |
That's odd ... I was told the opposite, that most tree sugars are more soluble in alcohol. Perhaps I misread the context of the statement... I'll
have to recheck the conditions. The largest weight loss in my experiments was with water; so what you are saying is consistent with the results I
have gotten so far.
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semiconductive
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| Quote: Originally posted by Bert | If you want to recreate the Stradivarius treatment, perhaps you should limit the chemical choices to those available at that period?
|
That's not actually my goal. I have harps which change their tuning as humidity changes. Harp sound boards are notorious for exploding under string
tension after moisture cycling for a number of years. Again, it's usually the xylose which gets attacked by funguses and dry rot ... weakening the
wood which eventually destroys a harp. Manufacturers sometimes use shellack, urethane, or other chemicals to preserve the wood -- but they deaden
the sound even more. To prevent breakage, it's also common to place a thick wood strip on the back of the sound board ... which makes the harp very
quiet.
So, my primary goal is to remove a certain amount of the xylose similar to Stradavarius violins, and then try to replace it with a hydrophobic
substance. The net gain and loss in resonance, would then hopefully cancel out.
My original idea was to try taking an alkoxy silicone, and impregnae the wood with just enough to replace the missing xylose. Hopefully that will
discourage water from entering the wood in the first place, not deaden the sound too much, and make the wood rot resistant.
| Quote: |
If you just want the same EFFECT, but quicker and surer/amenable to modern industrial control methods? And you already understand how this effect was
achieved?
Pressurized wood treatment with liquified gasses or chemicals born by such liquids should be faster than soaking to thoroughly permeate a plank.
Liquid CO2 or anhydrous ammonia treatments have been used by woodworkers for other effects, such as liquifying the lignin temporarily to allow complex
bending operations without steaming.
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Yes. Pressurized CO2, however, is difficult to work with. I have a scuba tank, and it takes about 800PSI to liquify CO2. I generally drop dry ice
into the tank, and then allow it to warm up enough that the CO2 drives air out of the tank. Then I plug it. Unfortunately, regular NPT thread pipe
tap (1 inch of threads) will still leak CO2 slowly out of the tank and it will empty. The tank uses NPS (National pipe straight) threads, about 2
1/2 inches long. Normal scuba regulators are expensive and useless for attaching CO2 under high pressure to other vessels ... so I tried buying a
straight bolt, 3/4" NPS, hoping to hit it with a torch to soften it ... and then drill and braze a welding fitting on it. Regular 3/4" grade 8 bolts
have the correct thread spacing ... but are too wide at the thread peaks to go into the 3/4" neck of the tank by a few thousandths at least. I don't
feel like dumping a lot of money into a buying another welding tank for a simple wood experiment ....
[Edited on 20-3-2018 by semiconductive]
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Thanks for the added info, i am sorry i am not much use. I am pretty good at thinking out side of boxs and hunting down info.
What type of wood are your instruments made of?
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semiconductive
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| Quote: Originally posted by NEMO-Chemistry | Thanks for the added info, i am sorry i am not much use. I am pretty good at thinking out side of boxs and hunting down info.
What type of wood are your instruments made of? |
The harp I just bought to do experiments on has a rose-wood frame. That's midlle-eastern rose-wood; not American. The sound board is going to be
made of western red-cedar; which is also fairly common in guitars. Right now I'm just focusing on making a new sound board. I have no intention of
treating the frame at this time. Generally speaking, spruce is the other wood which good harp sound boards made of.
Although balsa may sound strange for experiments, if you search for balsa wood fiddles and violins; people do in fact make them. So, the two woods I
have chosen to do experiments on are in fact used to make musical instruments.
The reason I chose balsa, besides the low cost and being simple to cut with a razor; is that the xylose is not protected by the lignin or cellulose.
eg: MIcroscope examination shows that the xylose is exposed on the cell walls where solvent can get to. Also: There isn't much oil in balsa, like
there is in redcedar. Both of these considerations should make it easier to chemically attack the xylose in balsa than redcedar. The simpler
structure gives me a chance to work out the chemistry of dissolving xylose with less complications.
Of course there is always a risk that something different in a particular species of wood will affect the process; but I don't think it will be a
major difference in chemistry with redcedar and balsa.
Balsa and western redcedar differ very little in the total amount of xylose they have in them and the monomers making up xylose. I think only one
sugar is entirely different. Rhamnose, vs. Galactose. eg: 0.7% Rhamnose in redcedar vs 1.5% extra galactose in Balsa in place of Rhamnose.
I'm expecting these differences are not sufficient to cause large changes in solvent efficiency; so what I learn with balsa will hopefully apply to
redcedar once the lignin is removed just enough to expose the xylose. But that's a future concern.
What I don't want to do, is dissolve the lignin and allow it to re-deposit in a way that makes a sticky mass out of the xylose. In fresh cut wood,
the cellular structure is open to flow of fluids ... but it could easily be plugged by re-deposited lignin. If the lignin is smeared out onto the
xylose, then I expect the chemistry will be even more difficult.
That's a major reason for avoiding a weak base like ammonia, because it happens to be an efficient solvent for lignin. That's also why hot ammonia
water makes wood very flexible and bendable, so it's excellent for "shaping" wood. eg: an alternative to steaming the wood.
But, the lignin is no longer in tight bundles around the cellulose once it's re-deposited from ammonia solution ... who knows where it goes.
[Edited on 21-3-2018 by semiconductive]
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If one looks at the various microorganisms with a specialization in eating the primary constituents of wood, are there any obvious "cuts" by dietary
preference of obligate anaerobes vs. obligate aerobic organisms such that one could choose which components would be consumed from the wood by
selecting an oxygen free or an oxygen rich "canal water"? From what I know of late renaissance Venice, the cannals were your sewer as well as your
transportation and defensive system. The high organic loading and accompanying bacteria would likely have kept Stradivarius wood soaking canal waters
pretty low in Oxygen, compared to what (less stinky) Venice canal water has now.
Re: CO2 tanks- Can't you just RENT a tank from a local carbonic gas supplier? We do this several times a year. Surely your local
homebrewers/commercial craft brewers could offer some pointers on gas handling equipment as well.
[Edited on 21-3-2018 by Bert]
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You got a problem using Balsa, i make model planes (blush) I am in the UK, but i know that all Balsa into the UK and America Is heavily treated to
prevent disease, They also use a huge amount of steam to sterilize it before they can import.
I suspect your working with something that is nothing like what your going to be up against, personally i would go for the more complex wood, it might
prove easier both now and in the long run. Any sugar that was or is in the Balsa has already had several processes done to it, so its unlikely to
resemble anything your up against. Unless your going to make them out of balsa.
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The other thing i thought of was fungi like dry rot, different fungi attack different things in wood, like wet rot eats different bits to dry rot.
Find the rot that like Hemicelulose most, and see what enzyme it uses or what else it uses to break it down.
This also might help.
Attachment: ohgren2007.pdf (289kB)
This file has been downloaded 321 times
Also first paragraph or so of this one and follow the references.
Attachment: mok1992.pdf (1.3MB)
This file has been downloaded 432 times
another interesting paragraph in that paper
[Edited on 21-3-2018 by NEMO-Chemistry]
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semiconductive
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| Quote: Originally posted by Bert |
Re: CO2 tanks- Can't you just RENT a tank from a local carbonic gas supplier? We do this several times a year. Surely your local
homebrewers/commercial craft brewers could offer some pointers on gas handling equipment as well.
[Edited on 21-3-2018 by Bert] |
I wish I could; but there are no local gas suppliers except NAPA auto parts. Everything else is at least one county away. I live in the country.
I'm in a nook on a river with a long drive to a bridge to anywhere. Even wine making supplies are at least a 45 minute drive away. It a royal pain.
The only nearby "Towns" are both "don't blink" as you drive through it, or you will miss it. All commercial stores in the area truck in the CO2 from
the next county. I'm not a commercial chemist, so it's not like I have a wholesale license....
But I do have a free 2500PSI scuba tank. If I knew where to order a pipe fitting from that would work long term ....
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| Quote: Originally posted by Bert | | ... are there any obvious "cuts" by dietary preference of obligate anaerobes vs. obligate aerobic organisms such that one could choose which
components would be consumed from the wood by selecting an oxygen free or an oxygen rich "canal water"? |
This is something that I am not even sure how to research in the literature. I agree, the canals ... if that's in fact where the wood was soaked;
would be far more anerobic. The issue with bacteria and fungi, is that given sufficient nitrogen they will attack the lignin and cellulose and not
just the xylose. Standard mushroom growing technique will simply add urea + plant growth minerals to pure cotton, paper, wood chips ... etc. And the
fungus will attack the cellulose. (but not completely break it down, for years...); so the trick with bacterial fementation is to culture a
particularly weak strain that is unable to attack the cellulose and lignin.
I will try setting up various experiments, but biological fermentation is an art....
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| Quote: |
This also might help.
|
Nemo-Chemistry, yes ... that's a very typical bio-fuel paper. It has a lot of similar information to others I have read. That's a good reference
for this thread, thank you!
There are several points in it that I'd like to highlight, perhaps redundantly... sorry, if you got the points earlier.
Corn stover, being vegetable matter, is thin walled like paper. The steam pre-treatment makes it go soft and break down into mush. So, it's not very
close to wood in mechanical structure ; but it is similar in chemistry. However, Steam treating wood is not a good idea before removing xylose. Your
concerns about balsa imports are theoretically .... valid.
The pores in the Balsa that I look at under a microscope (75x) are wide open; so maybe the balsa I bought is U.S. made. The fibers of cellulose are
clearly visible as wispy strands when scraped at ... so they aren't melted together. I don't think this stuff has been steamed much. Either that,
or someone is violating import laws. 
The common chemical issue that we both face is where the article talks about the formation of "inhibitors."
I think inhibitors are condensation products where freed/broken ?monomers? chemically react with each other because of high temperature. eg: that's
what "degradation" means in most fermentation papers. That problem is also what I'm concerned about when a really good solvent like strong ammonia
water is used ... because it allows tons of monomers to come into contact with each other and chemically react. The inhibitors are more chemically
resistant to chemical attack than the original wood. That's why they don't digest by yeast ... but unfortunately they aren't mechanically strong.
Paper manufacturers also find the more condensation/"degradation" products that occur, the weaker the final paper will be.
As a general useful note, the article you showed talks about the roles of lignin and hemicellulose with respect to cellulose: P 2504 -- "the two main
protective coats around the cellulose, hemicellulose and lignin, need to be removed or altered without degrading the hemicellulose sugars."
That's one of the more important points; wood is a composite structure with the cellulose fibers in "sheaths" similar to how man-made electrical wire
has insulation....
In both hardwoods and softwoods, cellulose is the most protected/encased material. In hardwoods like Balsa, the hemicellulose is the outermost layer,
followed by lignin, and finally a cellulose core. In softwoods, (red-cedar), the order is reversed. lignin is the outer layer, followed by
hemicellulose, and finally cellulose at the core.
Hardwoods can loose their hemicellulose with less disruption of the wood strength than can softwoods. Unfortunately, the best sound boards for harps,
violins, guitars ... are generally soft-woods.
So, I need to damage/modify the lignin a little bit -- in order that the solvents or enzymes can get to the hemi-cellulose in redcedar, but not in
balsa.
In most processes for biofuel, what is troublesome to me (esp with steam) is the coagulation and melting of lignin that prevents total removal of
hemicellulose from underneath lignin. This wouldn't be a big problem in corn stover as it's already ground up into a "mash". However, in wood ... it
becomes a bottleneck because you can "melt shut" the pores through which you are trying to extract the hemi-cellulose.
In any event, in the article you site ... figure 2. is really new and useful information to me.
The only problem is that they use two enzymes, both cellulase and xylanse; the report is only about the glucose freed from both. Notably, the article
glosses over that hemicellulose also has glucose as one of it's monomers. So, they aren't doing a good job of showing the effect of mere removal of
xylose on getting more access to the cellulose ... The results can be confounded with enzymes directly releasing glucose from xylose/hemicellulose.
Even so:
The cellulase and xylanase enzymes looks very promising especially when NOT used with SO2 or steam pretreatment. They are showing 75% hydrolysis at
72 hours of treatment.
Seems too good to be true to me!
There's no way to separate out the action of cellulase from xylase in these studies.... they were used together. So, I can't determine if xylanase
also hydrolyzes some cellulose ... xylase is a cocktail of enzymes according to the study. It might degrade the wood completely.
Even mechanical pretreatment generally frees sugars/monomers in the ~10% of xylose mass. Eg: about that amount of xylose doesn't really need to be
broken down by an enzyme; so the inital curve of graph 2 is perhaps accelerated by mechanically released sugars. The way I read the graph, the
enzymes effectively broke down 50% of the mass in 72 hours. So, the linear part of the curve is likey to extrapolate out over another 72 hours if
they had continued the experiment -- ending in 95-100% of theoretical yield even without steam pre-treatment. Of course, the enzyme cocktail is way
more expensive than steam -- I bet.
I also didn't realize one needed to use anti-biotic to protect the enzyme from bacteria destroying it! I didn't realize that was a problem when I
tried cellulase, years ago; Anti-biotic was not part of the cellulase formula sold to break down toilet paper in RV's ...
That's why I had yeast present too. Maybe theres another reason my experiment didn't work years ago!!
Perhaps adding borax would work as an anti-biotic without hurting the enzyme.... I'll see what the xylanse costs. If it's practical for experimenting
on red-cedar and balsa, I'll let you know! Edit: $20 for 100 grams from multiple sources. I mail ordered it. I'll first test it on cotton to see
if it also damages nearly pure cellulose. If xylanase is very selective, I can use it to help me verify what other solvents did and didn't remove.
Thanks for the article. That was very helpful.
[Edited on 21-3-2018 by semiconductive]
The second article is puzzling to me. Although xylose typically makes up 15-25% dry weight, hemicellulose (including mannose) is more like 30%. So,
it seems the second article is using a different definition of hemicellulose than many authors I've read.
This is the data I've collected:
--------------------------------------------------------------
Western red-cedar (softwood, gymnosperm), expected composition:
Lignin 30%
Cellulose 38%
Hemicell 25% (including mannan).
unknown 7%
Hemicellulose constituents for redcedar (AS PERCENTAGES OF HEMI-CELL MASS)
Mannose: 45% 180.16g/mol
Galactogluco-mannan -- 5-8% (540.476g/mol)
Gluco-mannan -- 37-40% (342.297g/moml) not soluble in KOH, alkaline boric acid is used
Xylose: 15-25% 150.13g/mol
Glucose: 15% 180.16g/mol
Galactose: 1.5-15% 180.156g/mol
Arabanose: 5 -10% 150.13g/mol
--------------------------------------------------------------------------------------
Bala wood, medium denstiy (hardwood/angiosperm), typical characteristics.
Lignin 25%
cellulose 42% -- crystallinity is around 80-90%, excellent!!!
Hemi-cellulose components (percentage of total wood mass):
Glucose 13.5% (non-cellulose)
Xylose 16.3%
Mannose 2.3%
Rhamnose 0.7%
Galactose 0.5%
Arabinose 0.2%
Total: 33.5% mass is hemicellulose.
------------------------------------------------------------------------------------------------------
An average hemicellulose molecular weight for mixed monomers is around: 260g/mol.
I figure that's a decent first try estimate to use for computing moles of various solvents ions, minimum, needed to effectively attack the
hemicellulose. eg: 1 CaOH molecule / molecule of hemicellulose monomer should be a decent estimate of the quantity of base needed to dissolve the
hemicellulose. That's why I chose 30mg of CaOH in my first experiments.
[Edited on 21-3-2018 by semiconductive]
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I live in a forestry area, its the main industry. I am off to see the forestry commission today as they have a main office 10 miles from me.
While its mainly pines and spruces around here, there is a guy up there i know fairly well. He works in the alternative energy building and the lab up
there, cant hurt to have a word with him. Regarding Enzymes, sometimes you can get microbes to cooperate and make them for you .
Sorry about the corn stover, i was mainly focused on the bit about water solubility, this says to me its something thats transported around the tree
alot. Therefore removal cant be too hard.
I know about the Balsa because I imported some last year, its really expensive and you have to offload most of it. The people are in Indonesia but
helpful, from an email i got from them i know they remove alot of material because they use some of it for fuel for cooking.
I will drop them an email see what i can find out
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semiconductive
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That's awesome. I live in an ex-forrestry area; almost all mills have closed around here. The timberland still exists, but the timber is mostly
shipped overseas or out-of state on trains.
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semiconductive
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Experimental solubility test: 1g CaOH : 30mL MeOH : 2.505g glycerol (99.5% anhydrous/U.S.P.) -- unexpected grey color resulted.
I think it's very weird how the same three chemicals can produce almost entirely different results when mixed in different ratios.
As I mentioned before, 100mg of CaOH -- colloidally dispersed into 1g of Methanol, will dissolve in 9g of glycerol and turn it yellow at room
temperature. At higher temperatures (70C), that mixture browned.
However, I got entirely different colors with a different mixture ratio:
I looked up the molar masses of CaOH and Glycerol, to study what that polymerization I noticed might have been caused by. I decided to mix CaOH to
Glycerol in the molar ratio of 1/2 : 1, because CaOH is divalent. I figured that would limit CaOH to one bond site per glycerol molecule or less. I
could mix the cheemicals up in a flask, evaporate off most of the methanol, and then transfer the mixture to a sealable vial and raise the temperature
until it browned. That way I could record the breakdown temperature, and have an idea of what the polymer was being formed by at the molecular
level.
I planned to raise the temperature from 40C to 70C in 5C increments, and note where the new mixture started browning as the "breakdown" temperature
of glycerol in alkaline solution. However, the color changes were totally different this time. It never turned yellow. Rather, I got an off white
colloidal suspension in the Erlenmeyer flask that was slightly green (if not a trick of my eyes). But it was definitely not yellow at all. If
anything, it was a light grey-green color. I was able to raise the temperature to 55C before it looked like it might be darkening even slightly (I
couldn't be sure), so I left it overnight in a water bath at 55C ... unfortunately, the thermometer slipped out of the flask water and it raised to
near boiling.
Still, the glycerol did not turn brown this time. It turned dark grey, and there was no hint of a burnt odor around it.
The tiny amount of remaining liquid methanol almost certainly boiled off through the vial's cap, and there was a vacuum inside the vial this morning
that sucked the teflon liner onto the top of the vial and held it. I will try the experiment again tonight, with a larger water bath ... but I
thought I'd post the experiment's results for reference.
Also, when I transferred the liquid from the Erlenmeyer flask to a vial... I thought everything had washed over except a very thin film of calcium
scum. But, in fact, when I washed the flask a glass clear substance on the bottom began to fog up. So, the polymer like substance was so clear this
time as to look like glass until I wet it with water. It condensed in parts of the flask where the magnetic stir bar didn't reach because the flask
bottom isn't flat.
  
From 30mL dry methanol, 1g CaOH powder (Mrs. Wages).
I computed that 2 mol glycerol : 1 mole CaOH, would be 1g * (92.0394g*2 / 74.093 g/mol) = 2.486g Glycerol. Choosing to add slightly excess glycerol
to offset any water, I used 2.550g Glycerol in the experiment.
Final yield after evaporating off methanol, and loosing unknown clear polymer accidentally...
11.654g - 7.909g vial tare + 19mg washed off of stir bar = 3.764 grams.
If it was just glycerol + CaOH, I would have expected a maximum mass of 2.550 + 1.0g = 3.550g but I got 3.764.
Considering I lost some material as polymer/precipitate before transferring to the vial, the final substance clearly has absorbed some methanol. I
will try bringing it up to 90C, and see if the vial looses any more mass with air blowing across it.
Edit: the mixture is hardening, at 90C + air, The vial has lost a little mass and is now 11.456g gross (-198mg) --> 3.556g net. The glycerol mix
holds its shape and is starting to pull away from the glass walls of the vial.
Edit 2: ... 2 hours later: 11.373g vial ( -80mg). --> 3.473g Net in the vial; vs. a theoretical 3.550g. The glycerine-CaOH has turned into a
solid and is turning increasingly lighter grey as it "drys".
Because drying typcially goes like exponential decay, I think there is less than 80mg of methanol still in the glycerol. Conservatively, the worst
yield is probably 3.393g ??
So, there was a net loss of around 157mg from the starting glycerol and CaOH in both the polymer, container transfer loss, and any water loss from
chemical reactions.
If glycerol was acting like an acid neutralizing the -OH from Ca[OH]2 , then I would estimate a water mass of 1g / 74.093 g/mol * 2 * 18g/mol H2O
= 486 mg of water likely would have disappeared maximum.
The actual mass lost is even less than the water that would be released from acid-base neutralization ?!
I'm definitely going to have to redo the reaction and prevent the unknown polymer loss, because the difference in mass is so small that the slight
loss of polyimer is likely a large portion of it. It's as if there's no chemical reaction at all ... but then why is the color changing?
Either glycerol + Ca[OH]2 doesn't neutralize as an acid-base reaction ... or possibly all the water is retained for crystallization.
Anyone else have any thoughts about what might be going on?
[Edited on 22-3-2018 by semiconductive]
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NEMO-Chemistry
International Hazard
Posts: 1559
Registered: 29-5-2016
Location: UK
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Balsa people tell me ALL Balsa is kiln dried, They mention it grows extremely quickly and dies very quickly, so its ideal for bugs. Apparently if you
look at most Balsa wood a couple of inches thick and slice it, you will find wood boring insect evidence.
So for sure we know its kiln dried and steamed to some degree, also they fumigate but wont say much on it. The forestry people say water a little heat
and salt, pref CALCIUM chloride not Sodium chloride....
Thats all I got but will keep looking.
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