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DJF90
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[*] posted on 9-4-2010 at 02:54


Metabisulfite hydrolyses upon addition of water: Na2S2O5 + H2O => 2NaHSO3
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Melgar
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[*] posted on 9-4-2010 at 03:16


I was going to do the silver mirror, but then I realized that I ran out of nitric acid to make silver nitrate with. And I left this big one-ounce silver coin I have at my girlfriend's house. So I'd like to try that test at some point, but I think the reaction with bisulfite would be proof enough. I finally just ordered some online because my stuff wasn't behaving, so I'll do that once it gets here.
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[*] posted on 9-4-2010 at 03:58


You could also form the adduct with 2,4-DNPH, and take a melting point. IIRC, there are tables published in Vogel for such crystalline derivatives.
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[*] posted on 9-4-2010 at 04:21


Thx DJF90!:)

Melgar for your silver mirror tests you do not need to make silver nitrate, just use your silver coin as an anode in KNO3 solution, you will be amazed how fast the silver turns into Ag2O, then dissolve it in aq. NH3!
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[*] posted on 25-4-2010 at 13:33


I finally made some acetaldehyde in pure form!

I used the setup that I posted in my previous attempts, but this time I drew it for better understanding, sorry for the shitty line leading!

The glass tube was filled with copper oxide pressed into small granules of about the diameter of 3mm. Copper oxide was made with anodic oxidation, as it seemed to me that this way the oxide is extremely fine.

At the startup I gradually increased the temp of the khantal wire (setpoint of TC1) to 500°C, but the rate of acetaldehyde evolution is also acceptable at 400°C so I decreased the temp to 450 and kept at that. (the acetaldehyde is decompose @400°C to CO and CH4 but this was external temp control, so the temepature in the tube during operation is surely below 350C or so I think...)
It should be noted that I melted a small capillary, made of glass that protrude into the glass tube and tried to control the temperature that way (TC2), but as it turned out it was a bad idea and totally unnecessary. And I have not got a temerature controller with such a high response that this layout would require.

I directly avoided the heating of the catalyst, so the heating element(Khantal wire) and the catalyst bed was separated (Heating part~15cm, catalyst bed~15cm).

Identifying tests:

1 I led the gases into cc H2SO4! which was first get a yellow colour then got hot and charred after about 20min.

2 I led the gas into ammonical AgNO3 and heated it, a solid black precipitate was formed.

3 I led the gases into ccNaOH, first it got a yellow tint then turned into red and a tacky melted polymer with an apple like smell settled on the bottom.

4 The gas absorbs in aq ammonia and the solution on drying give a crystaline compound.

5 The NaOCl solution gets warm and turns yellow upon absorbing the gas.

6 If you drop some ccH2SO4 into the condensate (pure acetaldehyde) the condensate immediately starts boiling and if you do not stopper the bottle immediately you only get char, othervise you get two layers, a black layer at the bottom, and a yellow-white layer above it, which smells like pinewood three?!

7 I also lead the gas into Ca(OH)2 with HCHO followed the org synt volt 2 instructions, and after the required weight increase of the reaction mixture I poured some additional HCHO solution into it, (because the HCHO smell was totally disappeared after the addition), and got a yellow colour, which after keeping the mixture @ 45°C for an hour turned intense red. and a fine yellow powder settled at the bottom. (I did not have the time to isolate the product.....)

It seems to me that I forgot something, but I always have this feeling, anyways:)

So based on this reactions the dehydrogenation mehod, which is noted for lower by products, works at home, and can be reproduced by anyone..

After the tests, the setup was being run for additional 12 hours, during which I collected 69g of acetaldehyde, I poured it into a vial with a srew cap, upon opening the vial the liquid began to boil which is not literally means boiling, If you open the vial and follow a dust particle with your eyes you can see that it goes up and down, and a condensate on the vial walls can also be observed, furthermore on every opening of the vial I heared a 'shssssss'.

Which amazed me is that after the refrigerator there was still a lot of acetaldehyde uncondensed, I do not know how much, I can only say that the best is to use it as is, I am sure that I do not bother condensing it next time...

I will make some pentaeritriol and modify the setup to make acetic acid from ethanol with car exhaust catalyst (Pt on Al2O3) in my next project, wich I wanted for a long time, and after this success I seems to me that it wont be that hard:)

Any comments or improvements would be appreciated!


Attachment: acetaldehyde exp setup.rar (34kB)
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[*] posted on 2-5-2010 at 20:06



Quote:

Quote:
While researching refractory materials I came across a high fired granular porous clay material which is used as an artificial soil for aquatic plants in decorative ponds and aquariums , as a substitute for ordinary gravel , and it occured to me that this might make a useful carrier for a catalyst . A similar material is a porous alumina which is used in water filtration as a substrate on which grow beneficial bacteria and algae , and this ceramic could be broken up into granules using a hammer , and the granules could also be useful as a porous substrate for carrying a finely divided catalyst .


I absolutely agree with your statement Rosco Bodine. Just like what I did and observed using the water filtration. It proves that this is very helpful carrier for a catalyst.
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[*] posted on 3-5-2010 at 12:32


I did the bisulfite adduct on some of the distillation product from my fermented sugar water. After a day or so, there was a fine precipitate on the bottom of the container, and the smell I recognized was gone. The trouble is, whenever I do a bisulfite adduct reaction, I always get just a tiny bit of the adduct, even if there's quite a bit in there. Here's what I do:

1. Add some sodium metabisulfite to denatured alcohol and wait for it to dissolve. Keep adding until no more dissolves.
2. Add the aldehyde solution to the metabisulfite solution. (metabisulfite solution is about 2/3 the total volume)
3. Wait for adduct to precipitate.

I'm not sure if I should just add bisulfite as the adduct falls out or what. And as I understand, metabisulfite needs water to turn into bisulfite. Maybe it takes a while for this to happen? In any case, it doesn't seem like you can actually find bisulfite that isn't metabisulfte, and if you order bisulfite, they send you metabisulfite. Also, I'm not sure what the adduct solubility is like. It seems to dissolve in methanol, but fall out in ethanol and isopropanol. Maybe it's different depending on the aldehyde. I've been testing with vanillin, since I can add a known amount of aldehyde and see how much precipitates, but I'm sure the other functional groups contribute to solubility.

Anyway, once I figure out how to do this reaction, I can quantify how much acetaldehyde I'm getting from fermentation.
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[*] posted on 3-5-2010 at 15:12


I also tried to coprecipitate the acetaldehyde with NaHSO3 but found it impractical, the NaHSO3 (Na2S2O5+H2O) is expensive and it is not really like Na2CO3+Ca(NO3)2, but for quantitative analysis purposes it may be usefull..

For purification of aldehydes see: http://www.sciencemadness.org/talk/viewthread.php?tid=10256#... Len1 post -Purification - stage 3- it contains a lot of usefull information.

I would distill off some liquid into cold ethanol out of the fermantation pot, an let is sit in a stoppered bottle filled with air under the sun for about a week, and smell it, if you cannot smell acetic acid, you only made very tiny amount of acetaldehyde.
I also did this experiment, but I poured some acetaldehyde into a prechilled PET bottle stoppered it and left it outside for about a week, the completion of the reaction could be seen on the shape of the bottle, after the addition of the acetaldehyde and closing of the bottle, the pressure increased inside it for about 0,5-1 bar, and after about a week the bottle was dented, upon opening it a strong smell of acetic acid could be smelled.

It should be noted however, that acetaldehyde is very volatile, when I tried to condense it @-20°C only part of the acetaldehyde condensed, despite of the very efficient chilling (the venting tube after the refrigerator was frosty) when I took a nosefull of the gases of the venting tube, the smell was still strong! Also, if you only notice an apple like smell, you only made ppm of acetaldehyde, It has a pungent odour, comparable with formaldehyde, but unlike formaldehyde its smell is pungent immediately after a nousefull of it..
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[*] posted on 21-5-2010 at 11:31


I do acetaldehyde synth yesterday in mybody from vodka :D
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[*] posted on 21-5-2010 at 12:18


I remember the one girl I was dating once worked in a refugee center for mostly burmese refugees. The one Burmese guy that worked with her always had this strong smell about him that I couldn't place. Now I realize it's acetaldehyde. Guess he must have been quite the lush...
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[*] posted on 22-5-2010 at 08:54


I did two more experiments to make acetaldehyde
I electrolysed copper onto khantal wire, then heated it in air to oxidize the plated copper into CuO then placed the wire into a ketene generator (the setup was the same described in organic reactions), first the setup was running at dull read heat, then heated I presume the maximum that the khantal wire is able to resist to.
At the max temp, there was a lot of gas generation, it was so much that i could lit it and the continuous flame was about 10cm long.
So I can state that this is the fastest and easiest method to genererate a shitload amount of acetaldehyde!
If I have time in work, I will take a HS-GC-MS spectra from each pure sample collected at the two temperatures, and from the first, made by pressed CuO catalyst.
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[*] posted on 22-5-2010 at 09:03


Without some isolation of the gas, you can't really say whether this was acetaldehyde. At higher temperatures (450+C) formaldehyde might predominate, or even smaller molecules. That said, I'm sure that if you can control temperature and flow rate adequately you should be able to generate useful quantities using your setup.
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[*] posted on 23-5-2010 at 09:33


I don't know if it has been repeated upon, but alanine (simple amino acid) and not beta alanine I believe, will react with dilute HTH to form acetaldehyde. One might also want to consider just using a virgin catalytic converter, and dripping Everclear through that, at room temp, and having a condenser hooked up. The hexavalent chromium/dichromate reactions to me are really not so elegant, and I always like to stay away from anything polluting. Always go green if you can. Just my opinion. It's more elegant, and it's also the right thing to do.
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[*] posted on 4-6-2010 at 08:01


I just want to give you a way to make acetaldehyde. A very simple one is by heating a mix of Calcium acetate + Calcium formate. Both calcium salts are very simple to make.
The reaction is the following
Ca(HCOO)2 + Ca(CH3COO)2 ----> 2CH3CHO + 2CaCO3.


[Edited on 4-6-2010 by john_smith]
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[*] posted on 4-6-2010 at 09:16


Hm, yes. But have you actually tried this? I don't doubt that some acetaldehyde does get produced (I see for example http://www.nature.com/nature/journal/v165/n4193/abs/165402a0... supports your idea), but depending on temperature, heating rate, admixture and so, different proportions of products would result. I recommend http://www.scribd.com/doc/28118713/Thermal-Decomposition-of-... , not for insight into this particular proposed way of making acetaldehyde but just for some idea of the variety of possible reactions (and by extension the need for fractionation and workup).

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[*] posted on 10-6-2010 at 06:34


Here are the HSGC MS results of the two samples made by completely different apparatus.. to my deepest suprise.. the composition of the two samples are identical.. eeh!!

5micro liter of the pre chilled stuff with a chilled syringe was injected to a HS ampoule and heated to 300°C the absorbing component of the GC tube was of poly ethylene glycol.

The components on the main spectrum in ascending order of the retention time:

Acetaldehyde: 1,93 min.. I can say.. that lab quality acetaldehyde can be made at home which is just awseome :cool:

Acetone: 2,17min

Butanal: 2,45min

Ethyl acetate: 2,513min

Diethyl acetal: 2,54min

Then: 2 butanon, ethyl alcohol, paraldehyde (4,8min), metaldehyde, dioxolane.

I would like to add that I used denaturated alcohol, which is mainly adulterated in my country with methyl ethyl ketone (2 butanone), that explains the 2 butanone peak, the ethyl alcohol peak is evident:)

Also I would like to add that more acetaldehyde can be produced by the lamp method according to the results, but it can be attributed also to error of measurements, I mean messing with prechilled 5micro litre syringe can really cause difference at paralell measurements.

More ethyl acetate is produced by the lamp method due to higher temperatures, also the amount of paraldehyde and the tetramer is more that I cannot explain taking into consideration the increase in the amount of ethyl acetate, these impurities are only a few percent of the total sample though.

Based on the results both setups are recommended for a trial to every home chemist:)

Acetaldehyde keten lamp vs tube reactor.JPG - 94kB
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[*] posted on 11-6-2010 at 14:20


Actually, I tried mixing calcium hypochlorite pool shock and alanine (from nutrition stores) and I have to say, this has got to be the easiest way by far to make small amounts of acetaldehyde. Look up "Strecker degradation" to see how the reaction works. I've also heard, though I can't verify it, that TCCA pool shock will give the corresponding nitriles rather than aldehydes.
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[*] posted on 11-6-2010 at 20:08


you are right there meglar TCCA makes nitriles from aminoacids very easily.

thankyou very much to both your self and jimmymajesty for pointing out another use for alanine
and a ketene lamp.




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[*] posted on 19-6-2010 at 17:36


JIMMY! Great experiment! I was going to suggest something similar, but don't have that kind of analytical equipment to hand. I've seen people rabbiting on about the idea of building mini catalytic reactors but rarely hear about practical attempts and have never seen a spectrum from one.

I'm kind of busy and can't read back to your other posts right now, but did you try depositing the copper onto zeolite for the cake? This is mentioned all over the patents regarding copper catalysts, as well as how trace impurities in the copper affects the process. Like, I think zinc helps produce MEK or butanal in the product, or something along those lines.

From memory, they use ?ZSM-10? zeolite as the support. The vast surface area the structure presents accelerates the catalysis. The specific pore size seems to also influence the selectivity of the process.

Of coarse, the patents also discuss how they deposited the copper from solution (easy stuff). Google around "ethanol copper zeolite patent" and you'll be underway in no time.

DCM, I've never seen bearing a flammable sticker in real life. I have a tank of paint stripper, a container of pure DCM for everyday solvent cleaning and an up to date reagent grade bottle from a laboratory supplier. None of them have flammable stickers. But it has now been upgraded to a potential carcinogen. Meaning it can have a skull and cross-bone sticker in place of it's old harmful cross. I bet all the older chemists aren't impressed! I'm not! Hopefully it's not another benzene. I haven't seen these stickers on paint stripper yet, which is odd as they are very high concentration sources of the solvent. They're still using the harmful sticker on both stripper and the reagent bottles.

I have a bone to pick with people constantly referring to things as toxic, when they're actually more like harmful. It seems anything with the potential to cause any harm is upgraded to toxic now. Whilst things that do present real risks (like cancer) still have a harmful sticker on them. Since irritant also exists, it makes me question precisely what harmful is still being used for by these people. To me, toxic means it creates a long lasting risk at everyday exposures. So benzene would be toxic to me, as it damages DNA and creates a long lasting, carcinogenic risk. DCM would fall into the same category for myself. Following that pattern of logic, I'd nominate DCM for a harmful cross (with harmful / irritant under it) and a skull and cross-bones (with carcinogen under it), as it is both immediately irritating and slightly dangerous in terms of exposure but also capable of longterm damage. Cyanide would be harmful, as (despite it being extremely dangerous) it does not accumulate or present a longterm risk. I would seriously love for them to produce a new sticker visually indicating something is a suspect carcinogen, like a simple double helix (or to write this under the skull and cross-bone, as they already do under the blanket, seriously outdated term poison). I would also like to see the NFPA 704 rating system used on the containers. It's on the sides of the trucks, it should be on the containers people will actually be handling. I worry when I see MSDS that take the safe route out and blanket list everything as dangerous to cover against liable action. It's like saying a relatively harmless drug is in the same category as heroin. Causing users of the former to think the latter will be the same in terms of risk. Failing those changes to the stickers, or in addition to them, I'd like to see an accumulation sticker to indicate whether acute exposure is going to build up. And I want all of those changes regulated by someone other than the chemical companies, who will plaster them all over everything as the carcinogens start lining up. Either way, what I'm saying is that I'm not happy with the level of information the quick references provide, and think it could easily be improved upon. And students should be taught precisely what each of the few new variations means.

In terms of extracting DCM from paint stripper, get the cheapest, nastiest stuff you can. They usually have more DCM in them. It's usually around 50-70%. It will also be mixed with a polymer to make it thick enough to paint onto vertical surfaces without it immediately running off or evaporating away. Before you distill it, wash it with some water. The water should start looking like someone's cum in it. There'll be opaque white goo floating around in it (the polymer). Throw out the wash, distill the remaining organic. Using a saline wash may help prevent loss of DCM, as some of it will end up in the aqueous phase using pure water. If you go straight to distillation with the polymer, you may cake it onto the flask. It boils like crazy under only moderate vacuum, but it's also not going to liquefy at the condenser all that well, so it'll end up spitting out the pumps exhaust. Go with atmospheric distillation given that it boils so close to body temperature and doesn't break down. It's a fairly 'fun' distillation given how easy it is compared to oxygen sensitive, high BP things that bump under vacuum.

Bulk pyridines from a catalytic reactor? One thing that really interested me about this method of producing aldehyde was that the product is part of the one pot pyridine synthesis (throw it all together, stir away). One can cheaply and easily ferment hundreds of liters of ~20% alcohol at home in a week or two using raw sugar and distillers yeast. The excess water can be quickly and cost effectively stripped by dumping in a bag of plaster I believe, then decanting from the cake. The remaining liquid can then yield 100% ethanol under a more reasonably sized vacuum distillation (which breaks the azeotropic mix). You could also simply warm up the drum with an immersion heater (even the plastic ones will take the heat) and gently strip the azeotrope off, then run it through a smaller volume vacuum distillation in the glass. Homebrewers of moonshine go as simple as putting a plastic bucket of alcohol inside another plastic bucket with a lid and then warm up the alcohol containing bucket, letting the azeotrope condense on the sides of the outer bucket. Catalytically produce aldehyde from the vacuum distilled azeotrope, feed it into the one pot. I wonder if this same catalytic method works for methanol to formaldehyde (another component of the one pot). Yes, I know about the niacin method. But this seems reasonably realistic if you wanted larger volumes of pyridine. Or, for myself, just for the fun of doing something involving both biology and chemistry. I've brewed up huge volumes of alcohol using distillers turbo yeast and raw sugar in a big 210l plastic storage drum with an aquarium heater. The drum was formerly used to internationally transport olives. Yum! :D And even featured a very nice screw on lid that could easily be ported for an air pump, lock or vapor outlet; with your condenser possibly being as simple as a roll of PB / PEX plastic plumbing pipe, secured to the lid using a push fit cold header tank connector (they sell them specifically for this pipe and they feature a rubber gasket). I just loosely put the lid on and let it go. It was so tough I could kick it around the floor and barely scratch it. It all cost next to nothing and took next to no effort. I 'sterilized' with a quick rinse of boiling water. I rolled the culture up in a 15l container before hand, using more clean methods (e.g. boiled water), then inoculated the 210l of water at 50% of the recommended sugar concentration, so as to avoid thermal death. Then poured in the remaining 50% once it had calmed down a little. I was using 25kg sacks of sugar from a bakery supplier (real, real cheap). The water in the bulk drum was straight from the tap. The rate of fermentation was hilarious. You can also yield other useful building blocks, solvents and reagents from the process. It's like a total synthesis, but without the total overkill. The appeal of going from something as simple as sugar, water and yeast is high for myself. In addition, yeasts can perform other interesting feats of biochemical manipulation. And the raw product of this method is a highly valued resource for those who enjoy getting very drunk, very quickly, very cheaply. Might I suggest sampling some 100% ethanol, or buying a nebulizer and blowing O2 through it at the same time (you could use the pump that comes will a full kit for aerating the fermentation, not that it really needs it, but it might help churn up the mix). Caution, ethanol + pure O2 + drunk people = extreme fire hazard. These methods would also be very easy to lay down at the small scale, starting from some off the shelf alcoholics grade, no name vodka. The fermentation is bulletproof, it's about the oldest, most well studied biochemical method committed to text. You'd yield around 40 liters of 100% ethanol from a 210l drum fermentation. And foaming isn't an issue at all given how simple the sugar supply is; it doesn't foam. I also doubt you'll get into that much trouble, if any, distilling your own alcohol if you can demonstrate that it's not intended for consumption (which is what the tax is there for). When it comes to chemicals, the law is more concerned with why you have it and how safely you can handle it rather than the fact you have it in the first place.

[Edited on 20-6-2010 by peach]
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[*] posted on 20-6-2010 at 11:32


Quote: Originally posted by Ephoton  
you are right there meglar TCCA makes nitriles from aminoacids very easily.


I requested a reference for this in the references section. You need pyridine tho :(




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[*] posted on 20-6-2010 at 17:47


Quote: Originally posted by mr.crow  
Quote: Originally posted by Ephoton  
you are right there meglar TCCA makes nitriles from aminoacids very easily.


I requested a reference for this in the references section. You need pyridine tho :(


See! Everyone loves pyridine! :D
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[*] posted on 20-6-2010 at 20:57


Quote: Originally posted by peach  
I have a bone to pick with people constantly referring to things as toxic, when they're actually more like harmful. [...] Cyanide would be harmful, as (despite it being extremely dangerous) it does not accumulate or present a longterm risk.
Under this theory, cyanide would be non-toxic. Because this is the internet, I will point out explicitly that this is absurd. Just as you don't get your own facts in an argument, you don't get your own language in public discourse. That is, unless you are in discourse with Tweedledee and Tweedledum; with them you can say anything you like.
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[*] posted on 20-6-2010 at 23:29


I also read patents how to make catalysts that for example increase the ethyl acetate yield, but I think the only product of value of catalytic dehydrogenation of ethanol is acetaldehyde, if I were to make ethyl acetate I surely will not make it this way.

The making of some hundred of pressed copper oxide pellets was really a pain. I was glad when I finished, that I will not have to in my rest of my life. I have the shivers of the simple thought of a 4%Zn 6%Mn 10%Co 80%Cu homemade catalyst, but If you have the time to make it I will be happy to try it out:)

I took a photo about the CuO catalyst, (before and after shots)
I also took some catalyst pellets after a 12 hours of run and broke them to show that also the inside parts are reduced, so It must be porous.

Attachment: CuO catalyst.doc (96kB)
This file has been downloaded 731 times

[Edited on 21-6-2010 by Jimmymajesty]
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[*] posted on 23-6-2010 at 16:56


Quote: Originally posted by watson.fawkes  
Under this theory, cyanide would be non-toxic.


It'd be classed as harmful, since it neither accumulates or causes permanent damage; it actually burns off quickly compared to other chemicals. Alcohol and tobacco (do they have a chemically additive sticker? :D) are both harmful and toxic at levels that are used everyday by vast numbers of people. They are also both flammable, alcohol for obvious reasons and cigarettes because they contain burn enhancers. They are responsible for hundreds of millions of deaths and they lack all three labels. As is table salt lacking it's harmful / toxic sticker due to the heart disease it causes when exposure is at realistically prominent, everyday excesses.

Quote:

The making of some hundred of pressed copper oxide pellets was really a pain. I was glad when I finished, that I will not have to in my rest of my life. I have the shivers of the simple thought of a 4%Zn 6%Mn 10%Co 80%Cu homemade catalyst, but If you have the time to make it I will be happy to try it out:)


Could you not skip the pelleting by depositing it onto a granular zeolite? Which'd also increase your surface area by orders of magnitude.

[Edited on 24-6-2010 by peach]
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[*] posted on 23-6-2010 at 19:00


The reference now in the RRthread speaks of using DILUTE HNO3 to generate an aldahyde from an alcohol. Mainly they speak of Benzaldahyde from BnOH but it could be adapted rather well for acetaldahyde. Im currently working with it to oxidise all the was to AcOH but the smell of Acetaldahyde is very very strong. After a period of ageing the mix one could just distill off the aldahyde or precipitate as the adduct.




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"I see a lot of patterns in our behavior as a nation that parallel a lot of other historical processes. The fall of Rome, the fall of Germany — the fall of the ruling country, the people who think they can do whatever they want without anybody else's consent. I've seen this story before."~Maynard James Keenan
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