Sciencemadness Discussion Board - The Short Questions Thread (4)

The Short Questions Thread (4)

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solo - 8-2-2022 at 14:31

Thank you for the time you've taken to reply, yes i appreciate your insight and would welcome the references you mentioned. Both of my inquiries you've taken time to assist me, your contribution is very positive and well received........solo

AvBaeyer - 8-2-2022 at 19:54

Solo,

Pleased to know you appreciate my comments. I must confess, however, that I was enjoying my after-dinner glass of port when I wrote my comments. I mentioned the nitration of 1-phenylethanol as a possible starting point which could be nitrated. I do not think that alcohol would survive nitration even if protected. I think starting from acetophenone would be a much better starting point. So much for that.

As for references, here is what I have and with one exception they are all patents.

Non-patent reference: J. Keck et al., Arzneim-Forsch., (1972), v22, 861 and 869 (two articles, synthesis and pharmacology)

For Synthesis 1 (per my previous post):
DOS 1,793,419 (Thomae)
BE 704,213 (Thomae)
US 3,536,712 (Boehringer Ing)

For Synthesis 2:
DOS 2,157,040 (Thomae)
DE 1,543,928 (Thomae)

Additional Patents:
DAS 2,354,959 (Thomae) - alternative synthesis
US 3.536,712 (synthesis)

DOS and DAS are German patents, that is all I can tell you.

My information comes from:
Dictionary of Pharmacological Agents
A. Kleeman, et al., "Pharmaceutical Substances, Syntheses and Patents," 4th ed, 2001 (Georg Thieme Verlag)
Merck Index

Happy reading! Now to my evening port.

AvB

solo - 2-3-2022 at 15:07

It came to mind that if i can manage to oxidice ethy acetate via some alkane intermediate , i can synthesise acetic anhydride.....any tips on how can i go about accomlishing this.......solo

ethyl acetate

acetic anhydride

Note: however i did read this "Alkanes usually resist oxidation with oxidising agents such as KMnO4, K2Cr2O7 etc. However, alkanes containing tertiary hydrogen can be oxidised to corresponding alcohols."

Note 2:how abot a transterification with totsyl chloride hecemaking it an acidic transterification adding sodium acstate to replace the totsyl chloride all sone in toluene.....just a thought

[Edited on 2-3-2022 by solo]

[Edited on 3-3-2022 by solo]

clearly_not_atara - 8-3-2022 at 20:48

If you have tosyl chloride, you can just make acetic anhydride from that by reacting with sodium acetate. Boom.

The problem with oxidizing ethyl acetate is that it will tend to oxidize at the acetyl carbon rather than the carbon you want to oxidize, giving instead ethyl glycolate or ethyl glyoxylate. Maybe if you tried to do a radical halogenation of benzyl acetate, instead, you could get acetic anhydride or acetyl chloride upon rearrangement. In fact, that might even be a good idea.

Attachment: he2011.pdf (866kB)
This file has been downloaded 128 times

mayko - 15-3-2022 at 05:53

I tried to grow some rochelle's salt crystals... it seemed pretty foolproof: neutralize potassium hydrogen tartrate with sodium carbonate until effervescence ceases, then let it slowly evaporate. Mine has become a thick syrup that refuses to solidify... has anyone encountered this?

solo - 15-3-2022 at 06:49

Quote: Originally posted by clearly_not_atara

If you have tosyl chloride, you can just make acetic anhydride from that by reacting with sodium acetate. Boom.

The problem with oxidizing ethyl acetate is that it will tend to oxidize at the acetyl carbon rather than the carbon you want to oxidize, giving instead ethyl glycolate or ethyl glyoxylate. Maybe if you tried to do a radical halogenation of benzyl acetate, instead, you could get acetic anhydride or acetyl chloride upon rearrangement. In fact, that might even be a good idea.

thaks for that, however a bit puzzled by this.....

"As swim said,I mean Dry distillation.(i did this method many times with Tosyl chloride and even Benzene sulfonyl chloride)

Try 2:1 and 3:1 ratio of sodium acetate : Aryl Sulfonyl chloride"

[Edited on 11-3-2022 by Waffles SS]

,,,,source Acetic Anhydride preparation thread

[Edited on 15-3-2022 by solo]

[Edited on 15-3-2022 by solo]

solo - 20-3-2022 at 19:28

.......well after doing the reaction with the ratios 3:1 , sodium acetate: toluene sulfonyl choride...using 30 grams sodium acetate : 10 grams of toluenesulfonyl chloride , i got 15 ml of a liquid, still not analysed or redistilled ther was no bang!!!, however i did place my reaction vessel in a metal cage ....just in case.....solo

solo - 22-3-2022 at 16:45

…… result, not promising…. I will do the reaction again and will do the reaction on a sand medium keeping temp at 80C …. Keeping reactants from carbonizing …..solo

note : Waffles can you give any other details on your procedure as i seem i didn't have any success....thanks

B4ABBE0F-2715-4160-9B95-F7EEC3B6330C.jpeg - 96kB

[Edited on 23-3-2022 by solo]

artemov - 31-3-2022 at 21:57

Can isobutyl nitrite be used in place of n-butyl nitrite for azide and dimethylglyoxime synthesis (I only have isobutanol)?

I keep reading about n-butyl nitrite in various synthesis, rarely other butyl nitrites ...

mackolol - 22-4-2022 at 06:56

Will plain lithium metal be able to react with phenylacetylene to form lithium phenylacetylide?
I know that one would generally use some sort of a strong base like lithium hydride or amide etc...

But what about the metal? Will it be strong enough to replace the hydrogen? If not, then why?

solo - 10-5-2022 at 03:26

goal is to make 4-amino acetophenone

theory....use ethyl p-aminobenzoate (benzocaine) and ethylacetate in a cleisen condensation in ethanol with Naoetoh , because its a base driven reaction the amine group on the benzene ring won't be affected....however the reaction requires Hcl in order to keep the reaction to the right, now since i want to decarboxylate the alpha-beta ketone that requires an acid and heat.

now all this acid use concerns me since the amine on the benzene ring can be affected , any thoughts of an alterantive or is my premise wrong and i could just heat the solution right after the alpha beta ketone is formed and avoid the use of an acid( whichi doubt) ....solo

solo - 11-5-2022 at 18:15

.....actually there was no need to be concerned with the addition of acid, and the possible reaction with the benzyl amine, after the claisen condensation reaction in order for the reaction to remain to the right.....solo

[Edited on 12-5-2022 by solo]

Texium - 11-5-2022 at 22:25

Quote: Originally posted by mackolol

Will plain lithium metal be able to react with phenylacetylene to form lithium phenylacetylide?
I know that one would generally use some sort of a strong base like lithium hydride or amide etc...

But what about the metal? Will it be strong enough to replace the hydrogen? If not, then why?

I don’t think it would work. Normally using a base like lithium amide or an alkyl lithium, it’s essentially just a simple acid-base reaction. You have a strongly basic anion that deprotonates the alkyne. Li+ as a spectator. With lithium metal, now there’s a redox reaction that needs to occur. Li needs to get oxidized from 0 to +1. Normally this is done by reacting the metal with alkyl halides. Good electrophiles. The metal reduces both the carbon and the halide so 2 Li + RX -> RLi + LiX. In your case, you don’t have a good electrophilic, you’re asking it to form lithium hydride as a byproduct instead. Doesn’t sound so promising. My recommendation, use NBS to convert the phenylacetylene to (bromoethynyl)benzene (I’ve done this reaction before- be warned, the product smells awful) and react that with lithium metal to get your lithium phenylacetalide plus LiBr.

solo - 13-5-2022 at 15:38

I want to chlorinate 4-amino acetophenone not sure if i have to use a metal as a catalyst FeCl3 with a chlorinaing agent.....i saw a reaction where they used TCCA in MeCN at RT for chlorination ....confused .....any suggestions as to chlorinating agent and solvent with or without a metal catalyst.....solo

AvBaeyer - 13-5-2022 at 16:09

Solo,

Solo:

4-Aminoacetophenone has been iodinated with KI/hydrogen peroxide.
Reddy et al., Synth. Commun. 38, 3894 (2008)

2-Aminoacetophenone has been brominated with KBr/sodium perborate i acetic acid
Roche et al., Tetrahedron Letters 41, 2083 (2000)

o- and p-aminobenzoate esters have also been halogenated similarly to the above but I cannot find the exact reference.

You should be able to accomplish chlorination of your compound with KCl/Oxone in water-methanol or water-acetonitrile.
do a Google Scholar search on papers by N.Narender using the terms "oxyiodination", "oxybromination" and "oxychlorination"to get leading references.

AvB

solo - 13-5-2022 at 19:21

.....thank you for your support and advice, slowly i'm working myself to the complete synthesis of clenbuterol......solo

AvBaeyer - 13-5-2022 at 20:00

Solo,

Here is the bromination of p-aminoacetophenone with NaBr/Oxone in aqueous acetonitrile. I expect that chlorination should also work with NaCl or KCl.

Lee, et al., Bull. Korean Chem. Soc. 23, 773 (2002).

AvB

[Edited on 14-5-2022 by AvBaeyer]

solo - 27-5-2022 at 18:56

Does a Claisen cross condensation need to be an anhydrous reaction? I seem to be getting my ester hydrolysed and no beta keto ethyl ester.....I've run the reaction 5 times with the same results even though i changed the addition of reagents in different order ....Hence a friend suggested i use anhydrous ethanol dry my esters....k.

AvBaeyer - 27-5-2022 at 19:08

Dry, very dry.

AvB

solo - 30-5-2022 at 09:38

......after distilling all of my solvents since i didn't have and anhydrous, the cleisen cross condensation finally worked for me after 7 attempts .....therefore 4-amino acetophenone with a MP of 105-106˚C was acquired with broken glass clear crystals ....thanks for the assistance......as the chlorination is next.......solo

solo - 12-6-2022 at 19:36

....i have terbutyl alcohol and need to make terbutyl amine, thought of first making terbutyl chloride with HCl then treating it with aqueous ammonia......any thoughts would be appreciated.....solo

DraconicAcid - 13-6-2022 at 14:05

Quote: Originally posted by solo

....i have terbutyl alcohol and need to make terbutyl amine, thought of first making terbutyl chloride with HCl then treating it with aqueous ammonia......any thoughts would be appreciated.....solo

That will probably work, although the presence of water might muck it up. It's an Sn1 reaction- the carbocation will form, and then react with whatever is closest. You might want to dissolve the ammonia in a non-nucleophilic solvent and then add the t-butyl chloride.

AvBaeyer - 20-6-2022 at 19:46

The reaction of t-butyl chloride with ammonia is destined for failure. t-Butyl chloride is a tertiary halide and will undergo elimination to isobutylene in the presence of ammonia more rapidly than any other reaction.

You can react your t-butanol with acetonitrile in a Ritter reaction to get N-t-butylacetamide. However, I would not bet on an easy hydrolysis of this compound to get t-butylamine. You will need to look up the hydrolysis conditions for such highly hindered amides.

AvB

clearly_not_atara - 20-6-2022 at 20:09

Might consider a Reformatsky reaction of chloroacetate ester and acetone, which eliminates to a 3,3-dimethylacrylate that can, as I understand it, attack ammonia as an electrophile "properly".

Of course, this route is totally different.

solo - 21-6-2022 at 19:17

......I saw this,....solo

Thermodynamic study of direct amination of isobutylene to tert-butylamine
Shangyao Gao
Chinese Journal of Catalysis
38 (2017) 106–114

Abstract
On basis of thermodynamic empirical equations, the thermodynamic parameters for the direct
amination of isobutylene to tert‐butylamine, an atomically economic and green chemical reaction,
were calculated. In particular, the equilibrium conversion of isobutylene under various reaction
conditions close to those used in industry was calculated and discussed. Isobutylene amination is a
temperature sensitive reaction due to its exothermic nature and isobutylene equilibrium conversion
decreases with temperature. However, kinetically, the amination reaction will be faster at a
higher temperature. Thus, there must be an optimum temperature for the reaction. A high pressure
and n(NH3)/n(i‐C4H8) molar ratio promote the transformation of isobutylene to tert‐butylamine.
Developing a highly efficient catalyst under mild reaction conditions is preferred for the amination
process. The reaction was investigated over a series of acidic zeolites. ZSM‐11 zeolite exhibited the
best performance with 14.2% isobutylene conversion (52.2% of the equilibrium conversion) and >
99.0% tert‐butylamine selectivity. The effect of reaction conditions on the performance of the
ZSM‐11 catalyst agreed with the thermodynamic results, which provides guidance for further catalyst
development and reaction condition optimization.

Attachment: Thermodynamic study of direct amination of isobutylene to tert-butylamine.pdf (568kB)
This file has been downloaded 80 times

Sulaiman - 21-6-2022 at 22:03

Quote: Originally posted by mayko

I tried to grow some rochelle's salt crystals.

The salt is deliquescent so I GUESS that some sort of dessicator is required.

Edit : just checked.. <30% RH to dessicate.

Also, decomposes above 55C

[Edited on 22-6-2022 by Sulaiman]

solo - 6-7-2022 at 08:16

Quote: Originally posted by AvBaeyer

Dry, very dry.

AvB

thank you , but tell me this in many of the articles read and videos viewed , the topic of the reaction being anhydrous only shows up when using NaH as a base but otherewise nothing in the use of the bases methoxide or ethoxide....why is that? Is it something one should know from the start .....I had my sample of 4-amina acetophenone analysed , and it turns out to be benzocaine and benzoic acid.....is it that the amine reacted with the enol or the base....quite confused ....I'm currently on test #13 and the same results even though i introduce the ethyl ethoxide last slowly with an excess of benzocaine ....but the results are the same once i add the HCl to keep the reaction to the right.....then heated to decarboxylate.......any hints , and yes i've run the reaction with anhydrous reagents, but the results seems to be the same.......solo

mayko - 6-7-2022 at 20:30

Quote: Originally posted by Sulaiman

Quote: Originally posted by mayko

I tried to grow some rochelle's salt crystals.

The salt is deliquescent so I GUESS that some sort of dessicator is required.

Edit : just checked.. <30% RH to dessicate.

Also, decomposes above 55C

[Edited on 22-6-2022 by Sulaiman]

Where are you getting this? I've never heard of any special drying apparatus being necessary. Wikipedia gives a melting point of 75C, a dehydration point of 130C, and a decomposition point of 220C so I don't feel too bad about heating the aqueous solutions.

I poked and prodded the syrup, dripped ethanol and acetone on the surface, smeared a thin layer on the side of the beaker, left a toothpick in... nothing. I would have thrown it out except I got lazy cleaning and then after many weeks of sitting I thought I saw mold in it... no, the syrup was crystallizing in a couple points! Within a day or so it was solid throughout. I saved a bit, redissolved the crystallized mass, and then used the residue as a seed. I now have a jumble of fat needles, not really the blocks I expect but I'm going to use them to reseed another round and see how that goes.

clearly_not_atara - 7-7-2022 at 07:46

It's on Wikipedia.

Quote:

Rochelle salt crystals will begin to dehydrate when the relative humidity drops to about 30 per cent and will begin to dissolve at relative humidities above 84 per cent.

mayko - 7-7-2022 at 11:04

"dehydrate" in that passage refers to the loss of water of crystallization, not crystallization from solution.

karlos³ - 8-7-2022 at 19:09

The benzylic bromination of 2-methylnaphthalene, using NBS, is ideally done in presence of a radical initiator, benzoyl peroxide is usually used for that purpose.
With such a radical initiator, I could use a number of solvents, as the benzylic bromination will in that case be the main- and not side reaction.

Tried it once without, solventless, 20h in a melt, and the yield was(side reaction aromatic bromination) just a third of the theoretical yield.

So, here is the question: can I use the 2,4-dichlorobenzoylperoxide(50% under some silicon oil, because explosive

) as alternative radical initiator?
I expect the answer to be "of course", but I figured it won't hurt to ask.

Tsjerk - 9-7-2022 at 09:56

I'm making 5-formyl vanillyl and after reacting vanillyl and hexamine, and adding HCl I dumped the reaction on ice. The reaction contains 55 grams water, 55 grams acetic acid, 50 ml 30% HCl, and about 50 grams organics. I dumped this hot mixture on 400 grams of ice of approximately 0 degrees.

Now what I didn't expect was this mixture to go below 0 degrees, but it went all the way down to -7 degrees. Why is that? What endothermic process is going on here?

DraconicAcid - 9-7-2022 at 10:20

Quote: Originally posted by Tsjerk

I'm making 5-formyl vanillyl and after reacting vanillyl and hexamine, and adding HCl I dumped the reaction on ice. The reaction contains 55 grams water, 55 grams acetic acid, 50 ml 30% HCl, and about 50 grams organics. I dumped this hot mixture on 400 grams of ice of approximately 0 degrees.

Now what I didn't expect was this mixture to go below 0 degrees, but it went all the way down to -7 degrees. Why is that? What endothermic process is going on here?

Ice melting is endothermic. Because you've got a lot of acid, that lowers the melting point just like salt would.

mayko - 28-7-2022 at 20:06

when nitrosyl chloride reacts with limonene, why does it add only to the cyclohexene double bond, and not to the 2-propene side chain?

Fery - 28-7-2022 at 22:55

Quote: Originally posted by Tsjerk

... adding HCl I dumped the reaction on ice... what I didn't expect was this mixture to go below 0 degrees, but it went all the way down to -7 degrees. Why is that? What endothermic process is going on here?

IIRC the mixture of ice and concentrated HCl solution produces quite low temperatures, you diluted HCl in other reagents but anyway you still observed the endothermic process

Fery - 28-7-2022 at 23:01

Quote: Originally posted by mayko

when nitrosyl chloride reacts with limonene, why does it add only to the cyclohexene double bond, and not to the 2-propene side chain?

Mayko that's true, but I do not know why. I'm not too much skilled in theory, I like practical chemistry more. Anyway it is nice experiment https://www.sciencemadness.org/whisper/viewthread.php?tid=15...

mayko - 29-7-2022 at 05:46

Yep, I've been wanting to try the limonene to carvone conversion for a while, finally getting set up and want to understand more about the mechanisms

solo - 18-8-2022 at 05:39

i want to nitrate this compound....being that the group is large and its an o,p directional i will get the p position.....my concern is if there will be any reaction with my side chain exposed to the sulfuric and nitric acid used to place the nitro group....i.e esterification of the alcohol function ...and it might affect the direction of the nitro placement...?........solo

Tsjerk - 18-8-2022 at 09:14

I guess you will eliminate water forming an alkene before forming an ester. I wouldn't worry about forming an ester as it would probably not effect direction of the nitration too much and it would be reversible.

[Edited on 18-8-2022 by Tsjerk]

solo - 18-8-2022 at 10:14

......thanks i though of making the nitronium ion first with sulfuric acid and nitric acid then add to my compound with some cooling...solo

artemov - 19-8-2022 at 00:36

Can BiCl3(aq) be made easily from Bi2O3? Do I need concentrated HCl or will dilute HCl do? I supposed I need an excess of the acid to prevent the hydrolysis of the BiCl3 in solution.

Bi2O3(s) + 6HCl(aq) = 2BiCl3(aq) + 3H2O

BiCl3 is difficult/expensive to get here, but Bi2O3 is cheap and easily available.

Thanks.

BromicAcid - 19-8-2022 at 03:53

I have never done said reaction but I know bismuth has a tendency to form oxychlorides. A cursory looks seems to indicate it's not as bad as zinc where the isolation of the anhydrous chloride itself is next to impossible but seems it might be difficult to do without that showing up as a contaminant.

artemov - 19-8-2022 at 23:31

Quote: Originally posted by BromicAcid

I have never done said reaction but I know bismuth has a tendency to form oxychlorides. A cursory looks seems to indicate it's not as bad as zinc where the isolation of the anhydrous chloride itself is next to impossible but seems it might be difficult to do without that showing up as a contaminant.

From what I read, the hydrolysis to form oxychlorides can be reversed/prevented by using an excess of acid.

Bedlasky - 27-8-2022 at 13:24

Quote: Originally posted by artemov

Quote: Originally posted by BromicAcid

From what I read, the hydrolysis to form oxychlorides can be reversed/prevented by using an excess of acid.

Yeah, that's correct. Dissolving in 1+1 acid is okay. Maybe even 1+2 would be good.

[Edited on 27-8-2022 by Bedlasky]

Bezaleel - 27-8-2022 at 14:51

The Bismuth question is related to its iodo-complexes discussed here.
I'm also interested in these complexes, but I only have Bi metal. I tried to dissolve it in ~16% HCl, but it did not dissolve at all, neither when boiled.
I then tried to dissolve the same piece in 53% nitric acid and it did dissolve, giving off NO as orange-brown fumes. The solution was neutralised with ammonia solution until pH paper showed the pH was > 9. A fine, slightly off-white precipitate was formed (would do a good job as a warm white pigment).
The precipitate was suction filtered on a piece of Whatman white band filter paper put on a coarse fritte. Approx. 10% of the precipitate ran through during the first filtration, but virtually all was filtered when the filtrate was run through the same filter paper again. The residue was rinsed by pouring water on it after the initial solution has run though (still under suction).

The residue was dissolved in the earlier used 16% HCl solution. Another 0.5ml 36% had to be added in order to dissolve all of the residue. Heating was needed.
Around 10% was spilled and when the spilled drops combined with drops of water in the sink, a milky liquid immediately formed. It is evident that in order to keep Bi in solution, an excess of strong acid is required.

[Edited on 27-8-2022 by Bezaleel]

artemov - 27-8-2022 at 23:19

Quote: Originally posted by Bezaleel

The residue was dissolved in the earlier used 16% HCl solution. Another 0.5ml 36% had to be added in order to dissolve all of the residue. Heating was needed.
Around 10% was spilled and when the spilled drops combined with drops of water in the sink, a milky liquid immediately formed. It is evident that in order to keep Bi in solution, an excess of strong acid is required.

[Edited on 27-8-2022 by Bezaleel]

Thanks Bedlasky.

Bezaleel:
Yes I am trying to make the red salt cesium pentaiodobismuthate.
This is the only color missing from my rainbow salt series. Hope it really turns out red! lol

Would just adding more 16% HCl dissolve all of the ppt, or is a strong acid (>30% HCL?) absolutely necessary?
I have some <20% HCl, but not >30%. Guess I might need to make a small amount.

I bought some cesium salt (expensive!) and Bi2O3. Waiting patiently for their delivery

Oh, I managed to make nickel chloride and lead acetate from nickel coins and lead shots using hydrogen peroxide and the respective acid (dilute HCl/freeze distilled vinegar). Not sure if it will work with bismuth. I dun have nitric acid and dun really want to deal with NO2.

[Edited on 28-8-2022 by artemov]

Bezaleel - 21-9-2022 at 16:44

Quote: Originally posted by artemov

Would just adding more 16% HCl dissolve all of the ppt, or is a strong acid (>30% HCL?) absolutely necessary?
I have some <20% HCl, but not >30%. Guess I might need to make a small amount.

16% solution should be fine, but an excess of acid is necessary to keep Bi dissolved.

solo - 27-10-2022 at 20:11

....what can i substitute Sulfolane with? DMSO?........solo

Rainwater - 11-11-2022 at 10:58

What is the easiest way to use Cl₂ gas given off by an electrolysis cell? Would love to turn it into HCl

Rainwater - 2-12-2022 at 05:07

What is a safe but difficult fractional distillation?

Where the 2 components are almost identical.
I've read that vinegar is difficult but has almost an 18c difference in bp and no azeotrope it doesn't seem that it should be hard. Running a liter now.
Edit:
when looking at the vapor liquid equilibrium i see the difficulty
Should be a good test

[Edited on 3-12-2022 by Rainwater]

solo - 9-12-2022 at 19:01

....original post was deleted

[Edited on 10-12-2022 by solo]

j_sum1 - 9-12-2022 at 20:32

Please comment on... MDP2P

By all means discuss the chemistry. But don't let it turn into something that will spoonfeed a procedure to some kewl whose only interest is class A drugs.

B(a)P - 15-12-2022 at 02:36

I have a procedure that calls for drying bromonitromethane dissolved in dichloromethane over sodium sulfate prior to evaporating the dichloromethane. Can I substitute the sodium sulfate for calcium chloride? Obviously sodium sulfate is easily obtained, I just don't have any on hand right now and am eager to get started.

solo - 24-1-2023 at 11:17

........not having any resuts looking for CuNiAlx catalysst, would like some help on its preparation or who sell it....solo

Dr.Bob - 24-1-2023 at 16:47

Quote: Originally posted by B(a)P

I have a procedure that calls for drying bromonitromethane dissolved in dichloromethane over sodium sulfate prior to evaporating the dichloromethane. Can I substitute the sodium sulfate for calcium chloride? Obviously sodium sulfate is easily obtained, I just don't have any on hand right now and am eager to get started.

Don't see any reason CaCl2 would not work well, it is not basic or reactive with that, as best as I can see. DCM should be fine as well. Good luck.

yobbo II - 31-1-2023 at 11:34

What is in Bakers No. 3 flux for soft soldering.
There is zinc chloride, anything else? and how much?

Cheers.

B(a)P - 31-1-2023 at 11:53

Quote: Originally posted by yobbo II

What is in Bakers No. 3 flux for soft soldering.
There is zinc chloride, anything else? and how much?

Cheers.

Ammonium chloride

Attachment: 564987s_v1.pdf (348kB)
This file has been downloaded 36 times

yobbo II - 2-2-2023 at 08:28

Thanks B(a)P,

Before I read the post I decided to make some myself. (Did not know it contained Ammonium Chloride).
Added some Zinc Chloride to water and a sup of HCl acid. The stuff works great. Far better than the paste type flux.
The paste type is probably far less corrosive etc, for electrics, but I am doing big rough stuff.

Cheers,
Yob

solo - 3-2-2023 at 06:04

Quote: Originally posted by solo

........not having any resuts looking for CuNiAlx catalysst, would like some help on its preparation or who sell it....solo

...found the information....

Catalyst preparation.
CuNiAlOx was prepared by the coprecipi-tation method. 1.44 g (5.96 mmol) of Cu(NO 3 ) 2·3H 2 O, 3.48 g (11.97
mol) of Ni(NO 3 )2·6H 2 O, and 6 g (15.99 mmol) of Al(NO 3 ) 3·9H2 Owere added into 150 mL of deionized water at 80 °C in a 250 mL flask,and under vigorous stirring, 60 mL of Na2 CO3 solution (1.415 mol)was added dropwise into the solution. The mixture was mechanically stirred for 5 h and then cooled to room temperature and filtrated.

Following, the filtrate was washed with deionized water to neutral,
dried at 100 °C for 5 h, calcined at 400 °C for 4 h, and then reducedunder hydrogen flow at 450 °C for 2 h. Finally, the obtained catalystwas denoted as CuNiAlOx. The catalysts denoted as CuAlOx, NiAlOx,and CuNiOx were prepared with the same procedure

......Sustainable Catalytic Amination of Diols: From Cycloamination to
Monoamination --Yajuan Wu

alexrandomkat - 14-2-2023 at 14:14

Is it generally safe to use allihn condensers and vigreux columns under vacuum? Esp for vigreux, all the little indents make me think twice, but given the size of each hole is small...

Morgan - 20-2-2023 at 17:52

Might someone know what these "natural lava stones" are made of and what makes them a bit pricey. They mention calcium. Perhaps they take a lot of heat to make as one reason for cost?

Hamster Chew Toy Lava Teeth Grinding Square Stone For Hamsters Chinchillas and Rabbits Mineral Stone
https://youtu.be/YTbHAg4aLhw

Another aspect is they don't crumble or become friable when heated like some "pumice stones" I have cracked when hitting them with a torch.
https://youtu.be/RET638sfKNk

solo - 20-2-2023 at 20:00

i want to tosylate the Oh function of a carboxylic acid, but don't know if the conditions for the process is the same as for alcohols, perhaps with its not the same....i've looked but have not found anything specific on the procedure if its possible.....solo

...at the end i want to substitute the totsyl wih CN. or is there a direct way to add the CN to the carboxyic acid OH position?

[Edited on 21-2-2023 by solo]

solo - 21-2-2023 at 08:49

the goal is to make a ketone from an existing carboxylic acid, but maybe if i use acetic acid and tosylate the OH and substitute with a halogen ...giving me a acid choride that i can easiy use to acylate the benzene ring....solo

Texium - 21-2-2023 at 10:53

It's not exactly the same. Tosylated alcohols are tosylate esters, while a tosylated carboxylic acid would effectively be a mixed anhydride, so much more labile. Based on a quick literature search though, it appears that benzoyl tosylate has been prepared in moderate yield either from benzoyl chloride and silver tosylate in acetonitrile (which would of course defeat your purpose since you are after the acyl chloride, and the stoichiometric silver is rough too), from tosyl chloride and sodium benzoate with a phase transfer catalyst in DCM, or from tosyl chloride and benzoic acid with triethylamine as a proton scavenger in acetone. The latter sounds the most promising, if you have tosyl chloride available.

Edit: just noticed it sounds like you're after the acetic-tosylic anhydride, which apparently can be prepared by the same methods I described above, or alternately from acetic anhydride and tosylic acid in toluene at reflux. Seems like a rather roundabout way of making acetyl chloride, and it depends on you having access to acetic anhydride or tosyl chloride, both of which may be just as hard or harder to acquire.

[Edited on 2-21-2023 by Texium]

solo - 21-2-2023 at 13:24

....thanks for the input, but my goal is the 4 amino acetophenone, i tried the claisen condensation....its just to delicate and just gave up on it and i have no access to acid chloride to acylate hence i chosen to go around and tosylate the carboxyic acid then swap with CN with (NaCN) and reduce to an amine with NaBH4/I in THF ...thereby acquireing the ketone and and amine which i will use to hang tert butylbromide....the end goal is clenbuterol ......solo

[Edited on 21-2-2023 by solo]

yobbo II - 22-2-2023 at 05:24

Is there a difference in the boiling points of Silicone oils of different viscosities?

Silicone Oil 50 cPs (Polydimethylsiloxane PDMS) - Dimethicone 50
and
Silicone Oil 350 cPs

which would be the best for a diffusion pump?

Thanks,
Yob

yobbo II - 26-2-2023 at 17:09

The Silione 350cPs has a boiling temperature of >315C

Yob

yobbo II - 26-2-2023 at 17:10

What % approx. of Barium Carbonate would be in rat poison (assuming the rat poison contains BaCarb)?
I was going to make some.
The wax blocks are only fattening the rats around here!

Yob

yobbo II - 6-3-2023 at 08:09

Breaking hot update on the rat poison................

I made some rat poisong using barium perchlorate (somewhere between 10 and 20%).
I was thinking that the perchlorate would be too unpalatable and that obtaing carbonate would give a more palatable feed.
The rats did not appear to be eating the stuff. I had also mixed some icing sugar with the meal and perk. to try and sweetin things.
Only small amounts of the meal (poison) disappeared but the rats are all gone!
The stuff appeares to be lethal and edible.

Yob

yobbo II - 23-3-2023 at 07:26

Can anyone suggest a heat sink compound for a very high temperature. It has to work at 320C to perhaps 360C.
It is between two stainless steel surfaces.

Cheers,

Yob

Rainwater - 23-3-2023 at 08:11

For easy to apply and moderately safe, I've had good experiences using
boron nitride based thermal paste. It dries hard and can be difficult to separate the parts.
The dust is also dangerous. It is electricly non conductive, chemically resistant. And not to expensive.
Some places sell 5cc for 10~20 usd, as a therm paste for cpu/gpu whish soft sets. The cheaper
Kind sets hard and is much cheaper. 500g for $25 last time I restocked.

Depends on what other specs you have.
That tempature range will ware out normal paste like materials.
Paste rated for the tempature range have lower conductivity values
usually below 40 W/mK

Soft metals are the way to go, requiring a pressure fit. Giving the best
thermal conductivity possible. Over 400W/mK depending on the metal used.

If you do not care about electrical or magnetic characteristics
then a wide range of materials will work.

If the parts will not be seperated under normal conditions,
a high temperature solder would work great, but then their stuck together.
Application will be difficult to.

yobbo II - 23-3-2023 at 11:08

It does not matter if the paste is electrically conductive or not. Magnetic properties are irrelevent.

I was thinking copper paste.
If I obtained something like this:
https://www.ebay.co.uk/itm/171155282670?hash=item27d9a65aee:...

Burned out all the organics at 400C (under argon ) and I would be lift with copper powder.
I could just buy copper powder.

I will be lapping the surfaces. Total area is about 100 square cm

Yob

[Edited on 23-3-2023 by yobbo II]

[Edited on 23-3-2023 by yobbo II]

Rainwater - 23-3-2023 at 12:36

That product is a high heat lubricant, dought it will have many organics if any. Likely clay/silicone oil with copper filler.
You can use annealed copper foil, will be same price and less work

Auto brake cleaner solvent

Chemgineer - 8-4-2023 at 12:26

I'm after some cheap non-polar solvent for some oil extraction and bought some brake cleaner last week.

It contains n-alkanes and isoalkanes as main constituents.

If I distil this would it be a useful solvent?

Texium - 8-4-2023 at 13:34

Assuming it doesn’t contain other volatile components that are problematic, that sounds good. Depending on what range of alkanes are in it you may even be able to fractionate it into portions with different boiling ranges. Also look for “non-flammable” brake parts cleaner. It is usually pure tetrachloroethylene. It seems to be getting more difficult to find, though.

redshield5 - 8-4-2023 at 18:12

Quote: Originally posted by Variscite

I bought some Clean Shot H2SO4 drain cleaner the other day, it says it contains inhibitors in it. It has a clear purple color to it. I was wondering if anyone knew what these inhibitors were? Ive done some research on this, but havent found much, some say they are flourinated. I would also like to know the purity of this stuff, ive read about suspected Se impurities (eek)! What could the applications and constraints be of this H2SO4 vs say technical grade?

[<a href="u2u.php?action=send&username=bfesser">bfesser</a>: added to subject field]

[Edited on 7/12/13 by bfesser]

Hey Variscite, I've gotten so used to reddit lately that I kinda forgot how old school forums work lol. But hopefully you can see my reply as a notification.

For what it's worth (and I've never tried this): My mentor (and I consider him a very reliable, skilled chemist), once described to me a method to clean H2SO4 from liquid drain cleaners.
He told me to add a few drops of 3% H2O2 and then gently simmer/boil until the solution starts fuming and turns clear, then remove from heat.

Not sure how well it works or if there are any dangerous "side effects" of this procedure, so PLEASE be careful and DO YOUR OWN RESEARCH before simply taking me at my word and carelessly boiling strong acids. Hope it helps you!

[Edited on 9-4-2023 by redshield5]

Texium - 8-4-2023 at 19:16

You just replied to a post from 10 years ago by a member who hasn’t been active in 10 years.

yobbo II - 10-4-2023 at 16:10

If starting a 3 phase motor (about 20kW) which is on a centrifugal pump, how big a generator do you need (I am going to run the 3 phase motor from a 3 phase generator). The power going into the generator is not an issue (PTO driven).
Reading on the net (AFAICS) you seem to need a generator that is much bigger than the motor.
Asking a generator seller I was told that the generator needs to be about 4 times bigger. A 20kW motor needes an 80kW generator.
Seems very big.
I have no control gear on the motor so no gentle start etc. I can arrange to have no water in the pump at startup so that may help.

I was hopeing to buy a 30kW generator and use that. It it big enough. The geneator is an old type (Brush, makers name) so the rating would be generous (I think).

TIA,
Yob

Rainwater - 10-4-2023 at 23:50

https://www.engineeringtoolbox.com/amp/locked-rotor-code-d_9...

A picture of the pump plate would be helpfull. Most large 3p motors have a "class" which tells you about what conditions the motor can withstand, and a "code" to calculate the startup current, so circuit sizing, thermal overloads, etc can be calculated.

Assuming 480v code "d", the math would look like the following
Full Load Amps
Power / voltes = amps
Watts ÷ (Voltage * √3) = Amps
20000 ÷ 480 * 1.732 = 24.22

Starting current
FLA × code_minimium = Lock Rotor Amps minimum
FLA × code_maximum = Lock Rotor Amps maximum
24.22 × 4 = 96.90 amps
24.22 × 4.49 = 108.77 amps.

Back to watts(KVA)
108.77 × 480 × √3 = 89800 watts or 90 KVA peek power

So now we get into the accounts screwing things up, selling you something that is not as described.
Most generators are advertised as their peek power output.
For example small generator usually can only continuously deliver 60% of the power they are advertised as. You have to read the literature and find the peek power and continuous power

Please do not run your pump dry. every time you do a gasket crys

[Edited on 11-4-2023 by Rainwater]

Chemgineer - 11-4-2023 at 11:14

Quote: Originally posted by Texium

Assuming it doesn’t contain other volatile components that are problematic, that sounds good. Depending on what range of alkanes are in it you may even be able to fractionate it into portions with different boiling ranges. Also look for “non-flammable” brake parts cleaner. It is usually pure tetrachloroethylene. It seems to be getting more difficult to find, though.

I have been fractionally distilling the above and I'm getting two main fractions, one at ~50 deg C and another at around 70 deg C.

I am confused which alkane or isoalkane these could be as the boiling pointds don't coincide very well.

Also the can states less that 5% n-hexane so i'm ruling that out mostly.

[Edited on 11-4-2023 by Chemgineer]

Texium - 11-4-2023 at 11:29

There could be a larger portion of mixed hexane isomers that would explain the 70° fraction. SDS aren’t always the most reliable and exhaustive things out there. 50° is kinda weird though since that’s between pentane and hexane. Only thing I can think of that’s close is cyclopentane.

What do these fractions smell like?

Chemgineer - 11-4-2023 at 11:51

Quote: Originally posted by Texium

There could be a larger portion of mixed hexane isomers that would explain the 70° fraction. SDS aren’t always the most reliable and exhaustive things out there. 50° is kinda weird though since that’s between pentane and hexane. Only thing I can think of that’s close is cyclopentane.

What do these fractions smell like?

You could be right with the mixed isomers, I have a bottle of that from a chem supplier and it smells very similar, not strong smelling really though.

The 50 deg C fraction has a slightly stronger smell, sort of reminds me of turpentine.

clearly_not_atara - 12-4-2023 at 08:34

Doesn't cyclopentane easily form a clathrate with water? Eg:

https://pubs.acs.org/doi/full/10.1021/ie800949k

Maybe you could try this with the 50 C fraction. The clathrates are of interest in water purification, but they might also be useful for purifying the cyclopentane itself.

solo - 23-4-2023 at 07:02

....unable to find physical properties of 2-(Tert-butylamino)-1-phenylethanone. I will do the Hinsburg Reaction check for secondary amines .....have been reacting 2-bromo acetophenone with tert-butylamine .....solo

Osmiridium - 23-4-2023 at 12:37

Quote: Originally posted by yobbo II

If starting a 3 phase motor (about 20kW) which is on a centrifugal pump, how big a generator do you need (I am going to run the 3 phase motor from a 3 phase generator). The power going into the generator is not an issue (PTO driven).
Reading on the net (AFAICS) you seem to need a generator that is much bigger than the motor.
Asking a generator seller I was told that the generator needs to be about 4 times bigger. A 20kW motor needes an 80kW generator.
Seems very big.
I have no control gear on the motor so no gentle start etc. I can arrange to have no water in the pump at startup so that may help.

I was hopeing to buy a 30kW generator and use that. It it big enough. The geneator is an old type (Brush, makers name) so the rating would be generous (I think).

TIA,
Yob

Yes, there's a huge starting current with such inductive loads. Many times higher than the normal operating current.
I don't know if your motor is connected as star or delta. But for starting it should be started in star connection (lower coil voltage) and for a higher torque this may be switched to delta afterwards. There are special switches for this.
In star the current and stress to the power source and motor coils will be lower.

Of course the generator should withstand overloading for a short time because in the starting process an electric motor is basically overloaded too. The problem here is overheating or it might even stall the engine. So the engine power might pose the next problem.
What you could do is to connect something in series, maybe three smaller single phase consumers to each phase to increase the overall resistance and limit power draw. It's just a bit difficult with a 20kW beast. In any case the generator should have a significantly bigger continuous power rating than the motor. I'd say at least 2 times bigger but its difficult to say. 4 times bigger sounds reasonable.

But with such a rotary pump it should be no problem to run it dry for a short time.

Volatility of sodium dichromate

j_sum1 - 28-4-2023 at 04:11

I have attempted to produce my own sodium dichromate by fusing pottery grade chromium oxide with sodium nitrate. The product was mixed with water and filtered resulting in a deep red-orange solution. This was boiled down and is now sitting in a vacuum desiccator with a dish of concentrated sulfuric acid. It is now nearly dry.

Two observations have confused me.

1. The sulfuric acid has taken on an orange colour. Evidently the dichromate is somewhat volatile and is absorbing into the acid. I did not expect this. Or maybe I am interpreting the situation incorrectly.

2. The crystals as they dry have become quite yellow -- more like a chromate than dichromate. Again this is unexpected.

Can someone help me understand what is occurring here?

DraconicAcid - 28-4-2023 at 07:27

Is it possible that you're getting Na2Cr2O7 <==> Na2CrO4 + CrO3?

solo - 24-5-2023 at 15:00

...need help naming this , PhCH (OMe)CH,CI...i can't find its physical properties under my naming it .....2-chloro-1-methoxy phenylethane....solo

…….just found it…..
(2-Chloro-1-Methoxyethyl)Benzene. CAS No.: 3898-26-8

[Edited on 25-5-2023 by solo]

Bedlasky - 25-5-2023 at 02:16

J_sum, that looks like you have some CrO3 in your product. Really strange result, CrO3 is usually formed in extremely acidic environment.

Jome - 25-5-2023 at 09:58

J_sum1:
Perhaps if the "drying acid" was to be mostly neutralized and a reductant like ascorbic acid were to be added, you'd see if it turns green which would indicate unpleasant chromates flying around...

If some of the nitrate decomposed to oxides, It'd go alkaline and therefore yellow but that doesn't explain why it went reddish orange when in solution, as if it it is dichromates. I've done the experiment with NaOH in addition to nitrate and Cr2O3, and it turned lime-yellow.

j_sum1 - 25-5-2023 at 19:06

It is still sitting there. I have not pulled a vacuum on it for a while. The solid material is a lighter orange than when I put it in. The sulfuric acid is dark orange: almost tarry-looking.

When I get around to it, I can use the crystals as an oxidant. I am assuming that it is a mixture of sodium chromate and sodium dichromate. I can bottle up the coloured acid which I assume contains chromic acid. It will be good for cleaning glassware.

Nothing wasted.

The surprise is the volatility. I was just not expecting any chromium compounds to migrate.

Post about strange blue liquid

Bedlasky - 4-6-2023 at 06:13

Hi!

Some time ago someone on this forum posted report on some strange blue liquid, which climbed on walls of the beaker. It was something organic, probably something nitrite related. I searched for it quite a long time in the forum engine and on Google, but I couldn't find it. I am not glad that I post this stupid question, but doesn't somebody here remember this post? It was really interesting, I never saw compound like that before.

andyloris - 4-6-2023 at 06:44

Glycine dizotization in HCl - blue nitroso product?

Bedlasky - 4-6-2023 at 07:24

Thanks! That's exactly it!

solo - 5-6-2023 at 10:00

...need help in method to aminate 2-Chloro-1-phenylethanol with tert butylamine...I thought of using DCM with a short time reflux , since 2-Chloro-1-phenylethanol is soluble in DCM and so is tert butylamine....to the target molecule 2-(tert-butylamino)-1-phenylethanol however not sure.......solo

[Edited on 5-6-2023 by solo]

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