Sciencemadness Discussion Board - The short questions thread (2)

The short questions thread (2)

Pages: 1 .. 6 7 8

stygian - 22-6-2010 at 16:18

A couple weeks ago I came across a word I cant remember. Triflication or trilication or something like that. Something like fermentation or microbial processing of biomass. Can't remember the exact word. Does anybody know it?

DJF90 - 23-6-2010 at 07:14

Trifurcation? i.e. the process of cutting into three (c.f. bifurcation of the tongue!) - would make sense in biofuel context due to the glycerol backbone...

mnick12 - 25-6-2010 at 05:07

I have a question, many of the members here are able to purchase chemicals and equipment from many of the larger chemical distributers. But when I look on thier web sites I see they do not ship to individuals or residential adresses. So my question is how are some people able to order from the larger chemical and science equipment distributers, but not others? Is there some secret? I have tried contacting a few through email and most of them refused (others did not even reply...). I have heard some people buy through smaller companies that re-sell the chemicals, but even they do not sell to individuals.

If anyone can help me that would be great, as I am getting tired trying to make every reagent I need.

querjek - 27-6-2010 at 09:52

In aluminum amalgam, is AlH4- formed in situ?

DJF90 - 27-6-2010 at 12:37

No, aluminium amalgam is a source of electons, which are the "reducing agent".

densest - 27-6-2010 at 12:58

@mnick12 - one way to get access to chemical suppliers is: start a consulting business. Get a business bank account, a business credit card, and a business telephone line. Run the business for 10-20 years from the same address. Order various non-chemical apparatus every now and then for projects. Then when the chemical company pulls a credit reference on you, it looks legit, and they will ship.

It helps if the use of the chemicals is legit - being able to explain exactly what you want and what it's going to be used for when the company calls is a big plus. I've even gotten a few samples for free that way

solo - 27-6-2010 at 21:00

I've been trying to find some physical properties for this compound without much success......

1-Phenyl-2-amino-3-iodopropane

noted some information on this patent but it too has been a challenge to acquire will post the request in the appropriate thread......solo

K. Shinohara, M Tamura and T. Hosoda, 1-Phenyl-2-aminopropanes. Japan Patent No.
10,914 (1964) June 17,196l. C.A. 61: 11930cd (1964).

not_important - 27-6-2010 at 22:00

Not getting anywhere with the Japanese patent, but there is a U.S. patent a year later that looks as if it might contain the same information.

Quote: Originally posted by solo

I've been trying to find some physical properties for this compound without much success......

1-Phenyl-2-amino-3-iodopropane

noted some information on this patent but it too has been a challenge to acquire will post the request in the appropriate thread......solo

K. Shinohara, M Tamura and T. Hosoda, 1-Phenyl-2-aminopropanes. Japan Patent No.
10,914 (1964) June 17,196l. C.A. 61: 11930cd (1964).

Attachment: US3193581A.pdf (563kB)
This file has been downloaded 636 times

spong - 29-6-2010 at 05:20

Hi, first post but I've been lurking for quite some time.
I'm going to try to make vanillin and for the oxidization of potassium isoeugenolate to vanillin, nitrobenzene can be used but it is apparently hard to keep a stable temperature and whatnot.
Instead p-nitrobenzoic acid or m-nitrobenzenesulfonic acid in alkaline water were suggested in the patents I've read.
I was just wondering if it's absolutely necessary to use p-nitrobenzoic acid and not another isomer like m-nitrobenzoic acid as I have benzoic acid and could easily nitrate it but would get virtually no p isomer. I have no toluene and the polystyrene method looks tedious.
Thanks

[Edited on 30-6-2010 by spong]

Citric and Acetic acid reaction with mno2

Random - 2-7-2010 at 14:53

Is there any reaction of citric and acetic acid with mno2?

mewrox99 - 6-7-2010 at 20:48

I ordered Sodium Silicate from a ceramics suppler. They sent me 'Sodium Dispex' instead. What is it? And is useful for anything other than a deflocculant

not_important - 7-7-2010 at 03:00

Appears to be the sodium salt of short chain polyacrylic acid CAS : 9003-04-7

http://www.reptox.csst.qc.ca/Produit.asp?no_produit=269712

watson.fawkes - 7-7-2010 at 06:47

Quote: Originally posted by not_important

Appears to be the sodium salt of short chain polyacrylic acid

It's similar in composition to the Darvan deflocculants. I don't know about the relative molecular weights of the polyacrylates, though. A search for "Dispex G40" or "Dispex N40" will yield more specific information. They're also used in formulations as viscosity modifiers.

JohnWW - 7-7-2010 at 06:59

Mewrox99, if you ordered sodium silicate (usual formula Na2SiO3, "water glass", so called because of its solubility) from a New Zealand supplier, but received that stuff instead, i.e. the sodium salt of a polymeric organic acid, you were obviously sent the wrong stuff. Under the NZ Fair Trading Act 1986 and Consumer Guarantees Act 1986 and Sale Of Goods Act 1908, you are entitled to return the "Dispex" at the supplier's expense, and demand that they either supply you with the correct stuff or else refund your money.

Na2SiO3, which has a polymeric structure with oxygen atom bridges, is used to make freshly-prepared silica gel (amorphous hydrous SiO2) by acidification of an aqueous solution, and the product is used as a dessicant in closed containers after heating in a drying oven to drive off the water. A solution of Na2SiO3 is also used to coat eggs as a preservative.

mewrox99 - 10-7-2010 at 02:38

I accidentally left a container of solid NaOH open for a few hours. Should I replace it.

[Edited on 10-7-2010 by mewrox99]

bbartlog - 10-7-2010 at 07:16

Depends what you need it for and how much money you have. Presumably you now have (slightly more) sodium carbonate and water contamination than before. For almost everything I've used NaOH for (soap, basifying stuff, making sodium salts) this wouldn't matter in the slightest. But if you're trying to achieve anhydrous conditions or doing serious analytical chemistry I guess it could be problematic.

Picric-A - 11-7-2010 at 07:54

Does anybody know where i could find a chart for the solubility of piperazine freebase in a variety of solvents (idealy things like DCM).

I am trying to make piperazine freebase from piperazine phosphate and thought the best way to do this would be dissolve the phosphate in NaOH (aq) then extract with DCM.

Thanks for any help!

d010060002 - 11-7-2010 at 09:47

Hi guys.

i was reading through a procedure on how to recycle Silver Chloride ( Recycling silver chloride, Edwin Thall 1981), and i came across a warning against the explosive nature of Ag(NH4)2+. I've never come across this ion before. Has anyone had any experience with it/ ways to make it?

JohnWW - 11-7-2010 at 11:05

I think that, due to the complexing ability of NH3, AgCl is soluble in concentrated NH3 solution with formation of the ammine complex.

Nicodem - 11-7-2010 at 13:22

Quote: Originally posted by Picric-A

Does anybody know where i could find a chart for the solubility of piperazine freebase in a variety of solvents (idealy things like DCM).

I am trying to make piperazine freebase from piperazine phosphate and thought the best way to do this would be dissolve the phosphate in NaOH (aq) then extract with DCM.

Why are you interested in solubility when you then ask about extraction? Solubility and partition coefficients do not correlate!
Anyway, it took me exactly 10 seconds to find the logP(octanol/water) for piperazine. It is -0.8 so you can forget about extracting it with a separatory funnel (logP -0.8 equals a partition coefficient of only 0.16!). A continuous extraction with a ethyl acetate would extract it, but with a separatory funnel you would recover only a part of it, though depending on how many times you would extract you could extract a large part of it. However, in no case would such an approach make much sense, because there are better approaches viable.

Satan - 11-7-2010 at 14:09

Maybe heating with excess CaO, then distilling from CaO with some inert gas to prevent formation of piperazine carbonate would provide clean piperazine. Calcium residues in glass apparatus can be cleaned with HCl, or safer way with vinegar. Piperazine phosphate has m.p. of about 222°C according to:
http://www.39hg.com/jp14e/14data/Part-I/Piperazine_Phosphate...

"However, in no case would such an approach make much sense, because there are better approaches viable."
Can you elaborate?

Nicodem - 11-7-2010 at 14:51

Quote: Originally posted by Satan

"However, in no case would such an approach make much sense, because there are better approaches viable."
Can you elaborate?

You already elaborated on it. Why using an extraction for a compound that can barely be extracted with anything but numerous ethyl acetate extractions, when you can just dry distil? I would use NaOH, KOH, or much more preferably Ca(OH)2 so that the glassware does not get damaged. A minimum water would not hurt to speed up the initial process as you would probably want to collect the hexahydrate anyway. For the anhydrous piperazine you would need to redistil from whatever drying reagent that is used, but anhydrous piperazine is required only for very few uses and I don't think it is required for whatever Picric-A needs it. Actually, I think that he could use piperazine phosphate directly, but that is his own choice.

Picric-A - 11-7-2010 at 15:24

Quote: Originally posted by Nicodem

Quote: Originally posted by Satan

"However, in no case would such an approach make much sense, because there are better approaches viable."
Can you elaborate?

So would this be satisfactory, dry (i will add a bit of water as yes i do want the hexahydate) distill the reagents under a (moderatly) high vacuum so i do not get solid piperazine clogging my condenser (it has a m.p. of 104degC.

mewrox99 - 12-7-2010 at 22:39

Two quick questions.

1.

Has anyone successfully made a persulfate ester?

I did a quick google search and found nothing.

2.

What level of toxicity does TATP have?

mewrox99 - 15-7-2010 at 05:34

This is a short question not related to science. What is the whimsy board?

the Z man - 15-7-2010 at 05:53

Is it possible to make lead nitrate by adding NH4NO3 to lead acetate solution, boiling down to destroy the ammonium acetate into acetamide and precipitate the Pb nitrate with alcohol? Then what is a way to destroy acetamide with simple chemicals as I don't want to throw down the drain a carcinogen? I know it's a weird way to Pb(NO3)2 but i couldn't get other methods to work.

JohnWW - 15-7-2010 at 05:57

Being an oxidizing acid, HNO3 should be able to dissolve Pb metal, in spite of being below H in the electrochemical series. Have you tried that?

the Z man - 15-7-2010 at 06:18

It would be much easier if I could get nitric acid

I also tried to precipitate it as hydroxide and react with ammonium nitate solution but I got a very little yield of white precipitate, even if I used large excess of hydroxide and when I tried to dissolve the precipitate in the boiling AN solution it didn't want to dissolve

d010060002 - 15-7-2010 at 06:51

I've been doing some simple electrolysis of water, with a PC power suppply giving 6 volts at 1.3 amps DC. I've been using spectroscopic carbons as both the anode and the cathode, and it takes me about a day to get one bottle of hydrogen (15 hours or so). I asked by physics teacher what i could do to increase the speed of the electrolysis, and he said that I could either increase the current or that I might have reached the limit of the surface area on the rods, and should add more. I'm just wondering if it's possible to run out of surface area on a rod/ if there's a way or finding out if i have.

Thanks

solo - 15-7-2010 at 07:18

In the Study posted they use THF as the solvent....first of all what is it's purpose in the reaction and can it be substituted by Chloroform or benzene or suggest something else, since i have no source of THF for this exploratory reaction.....thanks

Reductive Dehalogenation of Arylhalides and Alkylhalides with Zinc in
THF Saturated Aqueous Ammonium Chloride
Rahim Hekmatshoar,* Sodeh Sajadi and Majid M. Heravi
Journal of the Chinese Chemical Society
2008, 55, 616-618

Abstract
Alow-cost and highly effective zinc/THF-saturated aqueous ammonium chloride has been developed
for dehalogenation of arylhalides and alkylhalides in aqueous systems.

Keywords: Reductive dehalogenation; Zinc; Aqueous ammonium chloride.

Excerpt
Reductive dehalogenation: General procedure Compound 1-12 (1 mmol) was added to an excess
amount of zinc powder (0.260 g, 4 mmol) in saturated aqueous ammonium chloride (4 mL) and THF (2 mL) and
the mixture was stirred at room temperature; after 3-5 h the Zn powder had disappeared (Table 1). Unreacted zinc was separated and washed with water. Two phases of solution were extracted and then the solvent was evaporated and further purification was performed by flash chromatography to yield products.

[Edited on 15-7-2010 by solo]

Attachment: Reductive Dehalogenation of Arylhalides and Alkylhalides with Zinc ....pdf (60kB)
This file has been downloaded 973 times

jokull - 15-7-2010 at 09:44

In general terms, THF acts as a nucleophile in dehalogenation reactions. For the system you are interested in, THF is highly miscible with water (intended as protic solvent). Maybe you can use a mixture of short alcohols and ethers.

mewrox99 - 15-7-2010 at 22:55

Is there any easy way to turn perchlorate into chlorate

JohnWW - 16-7-2010 at 00:54

Why would you want to reduce perchlorate to chlorate, when the latter is so much more dangerous to handle, and perchlorate is more powerful as an explosive when it is detonated? Or perhaps you want to use some chlorate as an herbicide, especially to kill stubborn spreading grasses like kikuyu? For the latter purpose, farm supplies stores, such as RD1 and Wrightsons and CRT in New Zealand, may have a "technical grade" of it; I remember my father buying some around 1960 to kill some kikuyu, but that was before Roundup (which is not completely effective against kikuyu) became widely available.

[Edited on 16-7-10 by JohnWW]

mewrox99 - 16-7-2010 at 00:58

It's a fairly atypical thing to want since most people would much rather have perchlorate than chlorate.

Just wanna play around with it and possibly make a tetraminocopper(II) complex.

Searched there (agricultural suppliers), found nothing

[Edited on 16-7-2010 by mewrox99]

Jimmymajesty - 22-7-2010 at 12:09

Hi folks!

I want to make acetyl sulphuric acid.
Now the question is not how to make it, rather what properties it has? What can be done with that apart from making diethyl sulphate. Can it be isolated?
I am planning to lead ketene into sulphuric acid to prepare it. Any info on the substance would be very appreciated, I searched around the net but found nothing valuable..

Panache - 23-7-2010 at 18:01

Is silver powder really a risk to spontaneously combust in air, ie pyrophoric?

watson.fawkes - 23-7-2010 at 18:23

Quote: Originally posted by Panache

Is silver powder really a risk to spontaneously combust in air, ie pyrophoric?

It depends on how small the particles are. Plenty of metals become pyrophoric when the ratio of surface area to volume is high enough.

12AX7 - 23-7-2010 at 19:15

For a noble metal like silver, that seems rather remarkable. However, several PGMs are also known to be pyrophoric. Supposedly, the high surface area combined with their catalytic nature makes them particularly reactive; osmium forms the tetroxide spontaneously, though in bulk form, it's inert as anything.

Nickel is another one, though not a noble metal per se, it's not very reactive in bulk form. This is fairly important because it's pretty easy to make (thermolysis of the oxalate IIRC) and an important hydrogenation catalyst.

Tim

IrC - 23-7-2010 at 20:16

I have to doubt that for silver, I still have an oz of silver dust. No idea particle size but it looks finer than my 500 mesh Al dust. I can pour it over a table and wait till hell froze over. Sure it will slowly turn black I imagine especially if in an area with H2S or something yet I never saw any fires. Bought it trying to build a neutron detector using the borated paraffin and GM tube (which has yet to work). I must have a few dozen neutron emitters I built experimenting around mostly using Be plates and strong alpha emitters yet never have I detected a neutron. Fortunately I know they do emit neutrons so I store them pointed towards outside walls. You never know sitting in a room for years with these devices in storage right? Never got into it enough to buy a real detector as those things are expensive. Ni I know also will not go off on it's own as I have 10 pounds of the dust and it never did anything out of the ordinary either.

Possibly if you created conditions similar to a dust explosion and gave it a match but I would rather not burn my face off nor would I care to waste valuable madsci materials.

chemoleo - 25-7-2010 at 09:13

Is there a way to achieve the following reaction

Phe-CHO + X-CH2-CHR2 --> Phe-CH2-O-CH2-CHR2

Note this is formation of a benzyl ether from benzaldehyde... can it be done?

Alternatively, is there good way to start form the benzylalcohol to form the ether? I'd really rather not do the Na salt, that reacts with the halogen derivative (substitute X for Cl, Br etc).

entropy51 - 25-7-2010 at 10:39

Quote: Originally posted by Panache

Is silver powder really a risk to spontaneously combust in air, ie pyrophoric?

This paper seems to indicate that specially prepared Ag is indeed pyrophoric. I have my doubts about run of the mill Ag powder though.

Nicodem - 25-7-2010 at 12:48

Quote: Originally posted by chemoleo

Is there a way to achieve the following reaction

Phe-CHO + X-CH2-CHR2 --> Phe-CH2-O-CH2-CHR2

Note this is formation of a benzyl ether from benzaldehyde... can it be done?

Alternatively, is there good way to start form the benzylalcohol to form the ether? I'd really rather not do the Na salt, that reacts with the halogen derivative (substitute X for Cl, Br etc).

Not directly in one step from the benzaldehyde.
You need to use benzyl alcohol and alkylate it with your isobutyl halide (assuming R stands for inert alkyls rather than some groups that might have some neighbouring effects or having other reactive sites). The reaction is called the Williamson ether synthesis, a simple SN2 substitution, and as such it would be way more effective (higher yielding and less problematic) if you could reverse the roles of the reaction partners. That is, to benzylate HO-CH2-CHR2:
PhCH2Br + HO-CH2-CHR2 => PhCH2-O-CH2-CHR2

In any case you need the presence of a non-nucleophilic base. Sodium hydride is indeed commonly employed, but other strong bases work as well (t-BuOK, K3PO4 in DMF, powdered NaOH or KOH in THF, etc.).

PS: The shorthand "Phe" stands for the phenylalanine amino acid residue. The shorthand for phenyl is "Ph", so benzaldehyde would be "PhCHO" (or "BzH" by using the benzoyl shorthand).

The WiZard is In - 25-7-2010 at 16:19

Quote: Originally posted by Panache

Is silver powder really a risk to spontaneously combust in air, ie pyrophoric?

Just passing through on my way to alt.binaries.pictures.nospam.post-yourself-nude
and thought I would mention this publication which can be DL'd gratis.

DOE-HDBK-1081-94
Primer on Spontaneous Heating and Pyrophoricity

Sorry to say it mentions not silver.

Pyrophoric-800.jpg - 112kB

mewrox99 - 27-7-2010 at 03:50

Anyone know what the PiHKAL cover is meant to be? Is it like a mountain or something

Random - 27-7-2010 at 23:08

What is the real reaction between Ca(OH)2(aq) + NaHCO3(aq)?

solo - 28-7-2010 at 07:20

I need some assistance in selecting an Abbe refractometer to assist me in my studies of phenethylamines mostly .....as there are many types and scale and ranges......thanks ,....solo

Addendum. ...i found this

Abbe Refractometers ASTM D 1218. ASTM D 1218, ASTM D 1747, ASTM D 2159 (obs. ... hydrocarbon liquids that have refractive indexes in the range from 1.33 to 1.50, ... the refractive index n20D. (i.e. referred to light of the Sodium ...

..so clearly i need to get something in the range covering maybe from 1.3 to 1.7, but then that is why i need some comments on the matter.

Example:

Phenethylamine
Phenethylamine Structure

Phenethylamine

CAS No. 64-04-0
Chemical Name: Phenethylamine
Synonyms: 2-PHENYLETHYLAMINE;2-AMINOETHYLBENZENE;2-PHENETHYLAMINE;1-AMINO-2-PHENYLETHANE;AKOS BBS-00003597;3-AMINOETHYLBENZENE;LABOTEST-BB LTBB000487;FEMA 3220;BENZENEETHANAMINE;B-AMINOETHYLBENZENE;AURORA KA-7805;BETA-PHENYLETHYLAMINE;BETA-PHENETHYLAMINE;(BETA-AMINOETHYL)-BENZENE;B-PHENYLETHYLAMINE;RARECHEM AL BW 0047;PHENETHYLAMINE;1-Phenyl-2-amino-athan;1-Phenyl-2-aminoethane;2-Amino-1-phenylethane
CBNumber: CB0738336
Molecular Formula: C8H11N
Formula Weight: 121.18
MOL File: 64-04-0.mol
Phenethylamine Property
mp : -60 °C
bp : 197-200 °C(lit.)
density : 0.962 g/mL at 20 °C(lit.)
vapor density : 4.18 (vs air)
FEMA : 3220
refractive index : n20/D 1.533(lit.)
Fp : 195 °F
storage temp. : 2-8°C
form : liquid
color : clear, colorless
Water Solubility : SOLUBLE
Merck : 14,7225
BRN : 507488
Stability:: Stable. Combustible. Incompatible with strong oxidizing agents, strong acids.
CAS DataBase Reference: 64-04-0(CAS DataBase Reference)
NIST Chemistry Reference: Benzeneethanamine(64-04-0)

Attachment: petrotest_product_13-0285_en.pdf (373kB)
This file has been downloaded 5096 times

[Edited on 28-7-2010 by solo]

[Edited on 28-7-2010 by solo]

Nicodem - 28-7-2010 at 15:26

Quote: Originally posted by Random

What is the real reaction between Ca(OH)2(aq) + NaHCO3(aq)?

Ca(OH)2(aq) + NaHCO3(aq) <=> CaCO3(s) + NaOH(aq) + H2O

solo - 29-7-2010 at 17:12

Quote: Originally posted by solo

In the Study posted they use THF as the solvent....first of all what is it's purpose in the reaction and can it be substituted by Chloroform or benzene or suggest something else, since i have no source of THF for this exploratory reaction.....thanks

Reductive Dehalogenation of Arylhalides and Alkylhalides with Zinc in
THF Saturated Aqueous Ammonium Chloride
Rahim Hekmatshoar,* Sodeh Sajadi and Majid M. Heravi
Journal of the Chinese Chemical Society
2008, 55, 616-618

Abstract
Alow-cost and highly effective zinc/THF-saturated aqueous ammonium chloride has been developed
for dehalogenation of arylhalides and alkylhalides in aqueous systems.

Keywords: Reductive dehalogenation; Zinc; Aqueous ammonium chloride.

Excerpt
Reductive dehalogenation: General procedure Compound 1-12 (1 mmol) was added to an excess
amount of zinc powder (0.260 g, 4 mmol) in saturated aqueous ammonium chloride (4 mL) and THF (2 mL) and
the mixture was stirred at room temperature; after 3-5 h the Zn powder had disappeared (Table 1). Unreacted zinc was separated and washed with water. Two phases of solution were extracted and then the solvent was evaporated and further purification was performed by flash chromatography to yield products.

I was wondering if i can substitute THF with DMSO since they both have similar properties.....

"DMSO is an important polar aprotic solvent. It is less toxic than other members of this class such as dimethylformamide, dimethylacetamide, N-methyl-2-pyrrolidone, and HMPA. Because of its excellent solvating power, DMSO is frequently used as a solvent for chemical reactions involving salts, most notably Finkelstein reactions and other nucleophilic substitutions. It is also extensively used as an extractant in biochemistry and cell biology.[2] Because DMSO is only weakly acidic, it tolerates relatively strong bases and as such has been extensively used in the study of carbanions. A valuable set of non-aqueous pKa values (C-H, O-H, S-H and N-H acidities) for thousands of organic compounds have been determined in DMSO solution."

Nicodem - 29-7-2010 at 23:44

So, this thread became too huge to handle. I'm therefore closing it and opening the third short questions thread.

@Solo: Using DMSO would not be reasonable given its redox properties. THF was used just a cosolvent so try with something more proper, like ethanol for example. Also, before wasting any expensive substrate make sure to first verify the method by repeating it with one of the substrates reported in the paper - I have not yet figured why, but for some reason many Iranian papers are often partly fictional or even complete fiction. Your question about the refractometer is unlikely to get answered, because I doubt there are many still using refractometers in a chemistry lab. As I see it you will need two of them if you are unable to find one that covers the whole scale.

I guess all other questions were at least partially answered, but if any one feels it missed anything due to this thread manipulation, it is of course free to pose the unsatisfactorily answered questions again in the new thread and hope for a better reply.

[Edited on 30/7/2010 by Nicodem]

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