Sciencemadness Discussion Board - The short questions thread (3)

The short questions thread (3)

Pages: 1 2 3 4 5 6 .. 8

Mixell - 14-8-2011 at 18:03

When a bond is created, it releases the equivalent energy of the bond to the environment, right?
So for the reaction to be thermodynamically favorable, the energy of the bonds that are created should exceed the energy of the bonds that are broken?

Plastics Ben

Morgan - 23-8-2011 at 18:12

I have a heavy box of quarter inch thick 6 X 24 inch sheets of a milky white plastic with a glossy surface and paper coating each side to protect from scratches. But I don't know what kind of plastic it is. It is unaffected by acetone. Any ideas what tests I could do to determine the plastic?

watson.fawkes - 24-8-2011 at 05:28

Quote: Originally posted by Morgan

I have a heavy box of quarter inch thick 6 X 24 inch sheets of a milky white plastic with a glossy surface and paper coating each side to protect from scratches. But I don't know what kind of plastic it is. It is unaffected by acetone. Any ideas what tests I could do to determine the plastic?

It's most likely to be an acrylic polymer, as that's the bulk of tinted sheet plastic out there. Second most likely is polycarbonate, but I don't often see it tinted in trade.

Do you want to know the chemical composition for using it as a reagent, or do you want to select an adhesive, or something else?

Morgan - 24-8-2011 at 16:20

It was just some plastic leftover from a photography business where they would mount pictures to it and then cut around the figures with a bandsaw making little statues of a sort of people, pets, etc.
I thought I might find some use for it but wanted to know if it was acrylic or polycarbonate, my two guesses as well. I have been playing around with electrostatics lately and might use it in some way.
I could make one of these only 6 inches instead of CD size.
http://www.youtube.com/watch?v=R9JVSWfgleg
Or perhaps as a plastic base for an electrophorus if it is a good plastic for that.
http://www.youtube.com/watch?v=TO95iGtRVv0
Or maybe I could employ it as an insulator or structural component It's funny how sneaky high voltage is, how it can crawl over surfaces. I experienced that with this device I made a few weeks ago. It's odd how entertaining two thin streams of water can be.
http://www.youtube.com/watch?v=h4WvZAVQtjk

watson.fawkes - 25-8-2011 at 02:56

Quote: Originally posted by Morgan

I have been playing around with electrostatics lately and might use it in some way.

Whatever the chemical composition, it should be just fine for this. While you'll likely get better performance out of a specialty material, what you've got is good enough for basic experiments. My only advice is to clean the surfaces carefully before putting the material into service, in case there's a more-conductive surface coating or residue from the protective paper.

Mixell - 29-8-2011 at 06:29

What is the best way to reduce a solution of palladium nitrate to metallic palladium? May be aluminium metal in conjunction with chloride ions?

Benzhydrol Refusing to Crystallise

Picric-A - 29-8-2011 at 10:49

I reduced 8g of benzophenone with 3g sodium borohydride (1g excess- the borohydride was old and i though better excess than not enough) in 50ml of methanol. Refluxed for 2 hours then boiled off 25ml of methanol. The remainding cloudy solution was added to 200ml of ice cold water with 50ml of 20% HCl in.

At this point the benzhydrol should crystallise, instead i got a very slightly yellow oil remaining at the bottom and the aqeous layer went opaque white.

What is going on here and why is the benzhydrol not crystallising?

I tryed the reaction again on smaller scale and the exact same happened, no crystallisation at all

bbartlog - 29-8-2011 at 12:45

Quote: Originally posted by Mixell

What is the best way to reduce a solution of palladium nitrate to metallic palladium? May be aluminium metal in conjunction with chloride ions?

I would suggest ascorbic acid. But I don't know what the best way is and suspect it will depend on what you're trying to do. I suspect aluminium might have problems, either due to passivation or because aluminium nitrate is itself an oxidiser (but this I assume could be addressed by using enough elemental aluminium).

Mixell - 31-8-2011 at 15:11

Anybody knows what is the color of bismuth nitrate solution?
I would have expected it to be yellow/colorless, bur for some reason mine is green (made from nitric acid and bismuth, which was sold as 99.9% purity).
I added the nitric acid to the bismuth, and surely, a vigorous reaction has started (, I continued adding nitric acid when the vigorous bubbling had stopped (at this phase the solution was yellow), then I left it for 10-15 minutes and when I came back, the solution turned green. At the moment a small amount of bismuth is still dissolving in it, but it has retained its green color.

[Edited on 31-8-2011 by Mixell]

[Edited on 31-8-2011 by Mixell]

Picric-A - 2-9-2011 at 13:46

Green is probably dissolved NO2. This can be dealt by adding small quantities of urea which causes it to give off nitrogen forming the colourless solution. Alternativly passing a warm stream of air through the solution works.

Mixell - 2-9-2011 at 15:35

After passing large amounts of warm air through the solution, it is still quite yellow-green...

solo - 3-9-2011 at 14:41

Sodium Cyanoborohydride- A highly selective reducing agent for Organic functional groups
Cinto F.Lane
Synthesis
1975; 1975(3): 135-146
DOI: 10.1055/s-1975-23685

.....on page 144 the study talks about the dehalogenation while showing inertness to towards almost all functional groups, I'v iodated my primary alcohol with Hpo and I2 and resulted with an iodated OH as an HI salt , insoluble in water ....now DMSO can substitute Hexamethylphosphori triamide (HMPA), ....finally my question how is the w/u with NaCNBH4 not familiar with it , but sure its not the same as with NaBH4....Trying not to kill myself doing this procedure.....some have suggested using using ammonium chloride to kill the reaction while I thought of using Na2CO3.....I have searched but not found anything to satisfy me to go on.....thanks....solo

P.S.

I saw this ...."Tetrahydrooxazines 6c,h,i; General Procedure Using Method A
NaBH3CN (0.095 g, 1.5 mmol) was added to a stirred soln of oxazine
4c, 4i, or 4h (0.5 mmol) in AcOH (2.2 mL) under argon. The
mixture was stirred at r.t. for 2 h and poured into a mixture of EtOAc
(100 mL) and sat. Na2CO3 (100 mL). The aqueous phase was backextracted
with EtOAc (2 × 50 mL); the combined organic layers
were washed with brine (50 mL) and dried (Na2SO4). The solvent
was evaporated in vacuo and the residue was subjected to column
chromatography (silica gel).

...source,

Diastereoselective Synthesis of γ-Amino Acids and Their Derivatives from Nitroethane via Intermediacy of 5,6-Dihydro-4H-1,2-oxazines Bearing the CH2CH(CO2Me)2 Substituent at C3
Alexey Yu. Sukhorukov,
Synthesis
2009(5): 741-754
DOI: 10.1055/s-0028-1083360

http://ifile.it/3kzxacy

....although not the same reaction but the work up makes sense, pick up the organic material with the ethylacetate and kill the boro with the Na2CO3....but then i may be overreading in order to go forward....still need some input....

Attachment: sodium.cyanoborohydride.pdf (662kB)
This file has been downloaded 631 times

[Edited on 3-9-2011 by solo]

Mixell - 5-9-2011 at 09:24

Anyone knows what is the full reaction mechanism of dissolution of aluminium in the presence of hydroxide ions? A reference would be great.

Never-mind, managed to dig it up myself, if anyone else is interested: http://www.icnet.dk/alhiref/I0009EDC4.0/DOE%20aluminium_wate...

[Edited on 5-9-2011 by Mixell]

temp

questions - 5-9-2011 at 19:51

Hey guys, here's a random question;

If I were to take an ordinary glass jar (not made from pyrex or anything similar) and submerg it into acetone with dry ice in it at the temperature of around -77C, would it crack?

Roger86 - 8-9-2011 at 13:29

I just saw bitter almond aroma in grocery store, is it same stuff as bitter almond oil, and is there benzaldehyde in it?

edit. did some hard searching in english and found that its ethyl alcohol and propylene glycol and almond aroma.So is almond aroma chemically what?

[Edited on 8-9-2011 by Roger86]

ScienceSquirrel - 9-9-2011 at 07:50

It will almost certainly be a weak solution of benzaldehyde.

Chemistry Alchemist - 9-9-2011 at 10:30

How would I oxidize polystyrene to form styrene?

solo - 9-9-2011 at 17:27

Reference Information

Method of reclaiming styrene and other products from polystyrene based materials
US Patent 6018085

Abstract
A method of reclaiming styrene from polystyrene-containing materials contaminated with animal fats and/or vegetable oils. A solution of polystyrene from such materials in a solvent is heated in distillation equipment to depolymerize the polystyrene and produce a styrene fraction and a heavier fraction, the styrene fraction being separated from the heavier fraction. Prior to heating, an inert gas is used to purge the distillation equipment of oxygen. The method preferably is carried out at the lowest temperature which will achieve the desired rate of depolymerization.

Attachment: Method of reclaiming styrene and other products from polystyrene based materials .pdf (250kB)
This file has been downloaded 620 times

Morgan - 9-9-2011 at 18:09

Anybody have some information on this product, what combination of chemicals might it be made of?
http://www.uksealants.co.uk/product.asp?idproduct=91

bfesser - 9-9-2011 at 18:35

http://lmgtfy.com/?q=calofer&l=1

Looks like it's primarily sodium silicates. More trouble to separate than it's worth.

I wouldn't recommend using the short questions thread as a substitute for Google.

[Edited on 9/10/11 by bfesser]

Panache - 9-9-2011 at 21:37

Quote: Originally posted by questions

Hey guys, here's a random question;

If I were to take an ordinary glass jar (not made from pyrex or anything similar) and submerg it into acetone with dry ice in it at the temperature of around -77C, would it crack?

depends at what temperature the glass jar is at, if its at -77C, no it won't fail, if its at 400C, yes most likely it will fail. At room temperature its likely to fail depending on its design, cooling it slowly would minimise the chances of it failing, however it would not stop it smoking cigarettes, and as we all know, these cause cancer.

Morgan - 10-9-2011 at 01:19

Quote: Originally posted by bfesser

http://lmgtfy.com/?q=calofer&l=1
Looks like it's primarily sodium silicates. More trouble to separate than it's worth.
I wouldn't recommend using the short questions thread as a substitute for Google.

I spent a few hours reading about K and Na silicates and the hardening process using CO2 or other agents. I had already used Google, imagine that. It's those other proprietary ingredients I was interested in, kind of a materials science point of view.

Roger86 - 12-9-2011 at 01:08

If a reaction requires Raney nickel catalyst, can it be replaced with really fine powder of nickel, if i expect the reaction to need a lot more hydrogen?

I read somewhere that it should work, but i'd need 75% more hydrogen, but since hydrogen is dirt cheap, it's not really a problem.

bbartlog - 12-9-2011 at 05:39

Probably depends on just what you mean by 'really fine powder'. I would also expect that the first thing you would need more of is time, not hydrogen, but without a pointer to whatever it is you read I suppose I'm just guessing.

Picric-A - 12-9-2011 at 11:19

Quote: Originally posted by Roger86

If a reaction requires Raney nickel catalyst, can it be replaced with really fine powder of nickel, if i expect the reaction to need a lot more hydrogen?

I read somewhere that it should work, but i'd need 75% more hydrogen, but since hydrogen is dirt cheap, it's not really a problem.

Depends on how the 'realy fine' powder has been made. Most fine powders bought commercially have an oxide layer which will prevent hydrogen adsorbtion, rendering it useless for catalylyst use.

If you find a way of making very fine Ni powder under an inert atmosphear/liquid, then that should be usable as a catalyst.

Phthalic Acid - 13-9-2011 at 23:45

I'm looking to dissolve cupronickel coins in HCl then use ammonia to precipitate the NiCl2 from solution (as I believe the Cu2+ ions complex with it). My question is: when using hydrogen peroxide as an oxidizer, how much do I need to use in relation to the rest of the equation? Let's say 2 moles of HCl and 1 mole of coins. Do I use 1 mole of H2O2? Any help would be greatly appreciated =)

Mixell - 16-9-2011 at 07:53

Nickel also forms an ammonium complex if I'm not mistaken.
The H2O2 tend to decompose to water and oxygen (which mostly escapes from the solution), I suggest just add it in small amounts until all of the metal dissolves (stir between addition of H2O2).

dann2 - 17-9-2011 at 03:35

Anyone any thoughts on the reaction of Nitrites and Pb3O4 (Minimum) in the presence of Lead Nitrate and Nitric acid?.
It has been stated that Minimum will destroy Nitrites in a Lead Dioxide plating tank.

Hydrogen Peroxide cannot be used as it reacts with Lead Dioxide in the presence of Nitric acid.

Thnaks,
Dann2

Endimion17 - 18-9-2011 at 09:08

I was always wondering what exactly is a "chlorine bomb". There was a flood of videos depicting dumbasses pouring a liquid over a white solid and then shaking it closed tight. Some bottles blow into their screaming faces, and some blow with a delay.

I had trouble actually finding what are the ingredients (I see no chlorine being added) and the reaction itself. And I've noticed these videos come primarily from USA. I never ever heard someone doing that in Europe.

Thanks...

bonelesss - 18-9-2011 at 12:26

Quick google search :http://en.wikipedia.org/wiki/Chlorine_bomb

chlorine tablets and rubbing alcohol

[Edited on 18-9-2011 by bonelesss]

Endimion17 - 18-9-2011 at 14:12

You really thought I didn't think of Google and Wikipedia?

What are those "chlorine tablets"?

bonelesss - 18-9-2011 at 14:16

chlorine tablets are used in swimming pools.
But reason why it is used i don`t know

[Edited on 18-9-2011 by bonelesss]

hkparker - 18-9-2011 at 14:32

They are probably <a target="tab" href="http://en.wikipedia.org/wiki/Trichloroisocyanuric_acid">TCCA</a>, <a target="tab" href="http://en.wikipedia.org/wiki/Dichloroisocyanuric_acid">DCCA<a/>, or <a target="tab" href="http://en.wikipedia.org/wiki/Sodium_dichloroisocyanurate">NaDCC</a>. Im not sure of what the mechanism is behind its reaction with isopropanol however, or if chlorine is actually the main gaseous product; the name might come from a misconception.

Endimion17 - 18-9-2011 at 14:53

Quote: Originally posted by bonelesss

chlorine tablets are used in swimming pools.
But reason why it is used i don`t know

[Edited on 18-9-2011 by bonelesss]

Disinfection doesn't ring any bells?

Quote: Originally posted by hkparker

They are probably <a target="tab" href="http://en.wikipedia.org/wiki/Trichloroisocyanuric_acid">TCCA</a>, <a target="tab" href="http://en.wikipedia.org/wiki/Dichloroisocyanuric_acid">DCCA<a/>, or <a target="tab" href="http://en.wikipedia.org/wiki/Sodium_dichloroisocyanurate">NaDCC</a>. Im not sure of what the mechanism is behind its reaction with isopropanol however, or if chlorine is actually the main gaseous product; the name might come from a misconception.

Yeah, that's what I was thinking, but who knows what's inside.
Trichlor, dichlor, or sodium salts. Might even be a hypochlorite...

So it's isopropanol, not ethanol? Isopropanol is a secondary alcohol, therefore less prone to a nucleophilic attack than ethanol. That might put a new perspective on this, if we're dealing with trichlor and similar compounds.
BTW I'm surprised how easy is to obtain isopropanol in large amounts in USA. "Rubbing alcohol"... we use exclusively ethanol for rubbing here. Most people have no idea what isopropanol is.

I don't know whether this is a true chemical reaction between two compounds or just catalysis.

Can anyone try this at home? In a controlled environment, of course.

[Edited on 18-9-2011 by Endimion17]

hkparker - 18-9-2011 at 15:07

I"ve thought about doing it and capturing the gas(ses) for observation, however now that I am away from my lab that is not an option. I would be very interested to see the results however.

Rubbing alcohol is isopropanol here, ans it is very easy to get. Ethanol is actually hard to get except in alcoholic beverages and from some chemistry suppliers.

I'm sure anyone more experienced in organic chemistry then I am could offer an explanation, I might open a thread in the o chem section if it hasn't already been done in the past.

Roger86 - 19-9-2011 at 10:12

How much mercury could i extract from mercury lamp? Lets assume its 125W one.I want mercury while its still available, since the LED era has started.I read the readily available and it stated i should practice caution, is it because mercury is off the charts toxic, or is there a second source of danger?

Also i believe there are no mercury in modern mercury switches?

Panache - 23-9-2011 at 02:21

Quote: Originally posted by Roger86

How much mercury could i extract from mercury lamp? Lets assume its 125W one.I want mercury while its still available, since the LED era has started.I read the readily available and it stated i should practice caution, is it because mercury is off the charts toxic, or is there a second source of danger?

Also i believe there are no mercury in modern mercury switches?

Don't bother with the lamps, by some cinnabar from a minerals supplier, some mercury switches still have hg in them.

barley81 - 23-9-2011 at 08:59

I can buy 1L of either conc. phosphoric acid or glacial acetic acid. Which do you think would prove more useful in the long run? I have already 4 oz. of both.

AndersHoveland - 23-9-2011 at 10:04

If you typically are interested in organic chemistry, it is probably better to go with the acetic. If you work more with oxidizers or inorganic, better to go with the phosphoric.
Phosphoric can also be useful to make HI or HBr, which are both useful reducing agents in organic chemistry. HI, in the absence of water, can fully reduce ketones, removing the oxygen atom.

[Edited on 23-9-2011 by AndersHoveland]

barley81 - 23-9-2011 at 10:47

Thanks! Acetic acid it is. If I need HBr (solution) I'll make it from sulfuric acid, and I probably won't use HI regularly since iodide salts aren't cheap.

sponification of methyl salicylate and sodium hydroxide

Chemistry Alchemist - 24-9-2011 at 04:22

In the reaction of Sodium Hydroxide with and Methyl Salicylate do i need water to dissolve the sodium Hydroxide or can i just mix the the sodium hydroxide straight in to the methyl salicylate. I want to evaporate teh Methanol that forms with minimal to no water, and i cant distill off the methanol because i dont have the right glassware to do so.

bbartlog - 24-9-2011 at 04:53

Just mixing should work, leaving you (ultimately) with sodium salicylate and methanol. But I actually see no reason not to add water... what is your objection to applying a little heat to drive off the water? Sodium salicylate should be stable to quite a bit over 100C, and you could dry it in a short time at a mere 60C.
Note that what you are doing is not saponification, as your starting material is not a triglyceride. It is base-catalyzed hydrolysis. And be aware that concentrated NaOH can etch glass.

Chemistry Alchemist - 24-9-2011 at 05:03

in the reaction, does it produce any water at all or not? can i dry the methanol with sodium hydroxide or magnesium sulfate? i cant heat anything... i can only use the sun really :/ im planning on investing in lab ware, i really really do need more then what i have... im pretty sure sodium salicylate is more soluble in methanol right?

seperating calcium sulfate from ammonnium nitrate

Steve_hi - 29-9-2011 at 06:43

Hi hope this is the right place.
I am working on getting ammonium nitrate from fetilizer 27-0-0
I was told to mix it with water and decant it which i have done
now today I read from a previous reply to my post that I may have calcium sulfate mixed in is there a way to seperate the calcium sulfate from the ammonium nitrate and how can I test the ammonium nitrate for immpurities my immidiate use for some NH4NO3 will be to make some nitric acid.

hissingnoise - 29-9-2011 at 08:06

Filtering a hot, saturated solution of AN and cooling will precipitate fairly clean crystals.
But alkali metal nitrates are preferred for NA production because AN is subject to oxidation in hot H2SO4.

Chemistry Alchemist - 29-9-2011 at 09:15

If your just trying to separate Calcium Sulfate from Ammonium nitrate then just add enough water the the batch, Ammonium nitrate is easily soluble and will dissolve but the Calcium Sulfate is insoluble in water and can be decanted as you said, to remove some impurity, just add methanol to the AN, AN is soluble in Methanol and will leave behind any other impurity. then you can recrystillise the batch to obtain a better product

solo - 9-10-2011 at 13:24

.......CH3CH[NH2COCH3]CH3 how can i remove the acetyl group attached to the amine....Or reduce it to a methyl group....thanks for any tips, i have looked but not sure,......solo

P.S. ....i've read where hydrolysis will do it, can it be decarboxylated to leave the methyl group

[Edited on 9-10-2011 by solo]

fledarmus - 10-10-2011 at 04:03

Deacetylation of amines has always been a challenge. Strong acids and bases with heat will both work, but they tend to chew up the rest of the functional groups in your molecule as well. Doing a Google Scholar search for deacetylation of amines will show quite a few exotic attempts to do this, since it shows up frequently in protein synthesis.

mr.crow - 10-10-2011 at 20:20

Is hexamine soluble in dichloromethane? I only found information for chloroform

Identifying Chromate salts

Chemistry Alchemist - 13-10-2011 at 05:31

I recently extracted a chromium compound from pigment paint, its a Bright yellow salt... its either Strontium or Barium Chromate, how can i test? i know if i can get it to chloride or something and burn it, it will produce either red or green but how would i remove the chromium from the strontium or barium if u know what i mean?

Formatik - 13-10-2011 at 12:44

Quote: Originally posted by hkparker

I"ve thought about doing it and capturing the gas(ses) for observation, however now that I am away from my lab that is not an option. I would be very interested to see the results however.

I wouldn't try this out. Shrapnel pictures due to the reaction of ethanol vapor with TCCA (acetaldehyde formation attempt) are seen on page 2 of this thread: http://www.versuchschemie.de/hartmut.php?t=12979 The blast seen there was due to ethyl hypochlorite which accumulated and exploded.

A mixture of 30 to 35% pure calcium hypochlorite and absolute alcohol is reported to warm up on its own. Sandmeyer has distilled ethanol with calcium hypochlorite and obtained chloroform-containing ethyl hypochlorite. Sandmeyer characterized ethyl and methyl hypochlorite in the literature. The organic hypochlorites thread has more info: http://www.sciencemadness.org/talk/viewthread.php?tid=1896

The 'chlorine bomb' is due to virgorous exothermic oxidation of the alcohol releasing gases, of which organic hypochlorites might contribute to the explosion.

AndersHoveland - 14-10-2011 at 13:50

What is the difference between xylitol and arabitol? Why are they different isomers? Should they both not be able to interconvert with eachother since there are no unsaturated bonds?

[Edited on 14-10-2011 by AndersHoveland]

fledarmus - 15-10-2011 at 06:29

Quote: Originally posted by AndersHoveland

What is the difference between xylitol and arabitol? Why are they different isomers? Should they both not be able to interconvert with eachother since there are no unsaturated bonds?

[Edited on 14-10-2011 by AndersHoveland]

No, these are chiral compounds. If you make models of the two, you will find that there is no way to overlap them atom by atom, regardless of how many bonds you rotate. The only way to interconvert them is by breaking and making bonds.

Chiral alcohols similar to xylitol and arabitol can be interconverted by oxidizing them to the ketone, then reducing them back to the alcohol. If this is done under achiral conditions, you will obtain a mixture of the R and S isomer, but this is such a useful interconversion that there are a wide variety of reaction conditions available to let you choose which isomer your reaction produces. I don't know whether this interconversion has been published for this particular substrate.

Pope - 18-10-2011 at 20:45

Will Tetrahydrafuran react with pure copper in anyway?

AndersHoveland - 19-10-2011 at 00:02

Quote: Originally posted by Pope

Will Tetrahydrafuran react with pure copper in anyway?

I am fairly certain there would not be any reaction.

Calcium Nitrate with out Nitric Acid

Chemistry Alchemist - 19-10-2011 at 04:15

What is the best way to synthesize Calcium Nitrate with out using nitric acid...

NaNO3 + CaCO3 = Na2CO3 + Ca(NO3

2
Extract by the solublility but still bad contamination

NH4NO3 + Ca(OH)2 = NH4OH + Ca(NO3

2
Extract by Decomposing the Ammonium Hydroxide and leave Calcium Nitrate

NH4NO3 + CaCO3 = (NH4

2CO3 + Ca(NO3

2
Extract by decomposing Ammonium Carbonate and leaving Calcium Nitrate

Are there any possible routes other then i said up the top?

AndersHoveland - 19-10-2011 at 11:19

Perhaps refluxing calcium carbonate, ammonia, and hydrogen peroxide together.

Quote: Originally posted by Formatik

conditions can ammonia be oxidized to NH4NO2, the Ber. ref. from Hoppe-Seyler describes it... strong solutions of H2O2 with a few drops of NH4OH or solutions of ammonium carbonate (with or without NaOH or Na2CO3) can be let to stand 24 hours without any nitrite formation occurring. But upon longer standing, even with a small amount of hydroxide then nitrite forms. H2O2 forms (even in very dilute solutions) nitrite very rapidly, if the H2O2 solution is mixed with a few drops of NH4OH and a little NaOH or Na2CO3, and this then boiled in a retort to a very small volume. They suggest this nitrite formation as a demonstration experiment because it is very quick to do, and then after acidification of the colorless liquid with H2SO4, the HNO2 can be nicely be proven to be present. Excess H2O2 would oxidize the NH4NO2 to NH4NO3.

Chemistry Alchemist - 20-10-2011 at 04:36

So in other words, Calcium Carbonate and Ammonium Nitrate would work? just heap both up untill Calcium nitrate forms, and then boil off the Ammonia?

Panache - 28-10-2011 at 22:35

Is there much UV absorption to the silicone rubbers? They share the Si-O linkage with quartz like materrials and if one were to speculate from this the conclusion coud be its unlikely they absorb (the silicone rubbers that is). Does anyone know of additives for the rurbbers that allow they to absorb if in fact they don't. Any links to good sites on this topic woud be appreciated.

Endimion17 - 7-11-2011 at 09:33

It's always cold when you put your hand in a dessicator.
I know why, do you?

[Edited on 7-11-2011 by Endimion17]

Panache - 10-11-2011 at 15:46

Quote: Originally posted by Endimion17

It's always cold when you put your hand in a dessicator.
I know why, do you?

[Edited on 7-11-2011 by Endimion17]

Endimion17 - 10-11-2011 at 17:53

Because the inside air is very dry. If you stick your hand inside, the equilibrium is greatly shifted towards the evaporation of water from your hand, which requires energy that hand readily provides.
It's the same, whether it's winter or summer. If the desiccant is very strong, like it ought to be, you'll experience a cool sensation.

Panache - 15-11-2011 at 01:17

Quote: Originally posted by Endimion17

Because the inside air is very dry. If you stick your hand inside, the equilibrium is greatly shifted towards the evaporation of water from your hand, which requires energy that hand readily provides.
It's the same, whether it's winter or summer. If the desiccant is very strong, like it ought to be, you'll experience a cool sensation.

I was only answering your question not asking a further question.

OMG WTF PWNT!,,,,,,m,,,

Am only joking, I thought it would be something obvious, thought about it for a few days.

Sedit - 26-11-2011 at 18:14

Does anyone know the resonance frequency of the Benzene ring, IE: What frequency of Electromagnetic radiation would effect it in a similar fashion that Microwaves resonate NH3?

I post a more complex question once I get a responce to this one.

smaerd - 27-11-2011 at 13:59

Does anyone know if one could use and over-head stirrer type assembly(greased metal bar) through a rubber septum for an air-tight seal? If not is there any cheap quick DIY fix?

Nicodem - 29-11-2011 at 10:33

Quote: Originally posted by smaerd

Does anyone know if one could use and over-head stirrer type assembly(greased metal bar) through a rubber septum for an air-tight seal? If not is there any cheap quick DIY fix?

It would only be air-tight if there is not much pressure difference and if the hole was well cut and tight. If you use a balloon to keep the internal overpressure, then the air-tightness is not much of a problem (if inert atmosphere is all you need, rather than trying to control gas leakage).
A too wide diameter of the shaft might also cause friction related problems. You might just as well use a radial shaft seal of the corresponding size. It would also do a better job in keeping the spinning shaft aligned to prevent rough vibrations.

Panache - 3-12-2011 at 22:31

Quote: Originally posted by smaerd

Does anyone know if one could use and over-head stirrer type assembly(greased metal bar) through a rubber septum for an air-tight seal? If not is there any cheap quick DIY fix?

Vacuum or over pressure?
For vacuum, a ground glass joint, the minimum size that fits your shaft, once perfectly in place and firmly clamped can be packed out with teflon tape. Basically tie the teflon tape onto the shaft above the joint, turn on the stirrer and with tenion let the tape unwind down the shaft, build up a knob that will creep down into the cavity between the shaft and the joint, applying tighter tenion from time to time pushes the knob down until it has filled the joint.
Take some practice but is quite simple to master. You can then lower the shaft further if wear occurs duing your run. Placement of hose clamp above he knob wll help with creep upwards in case you haven't got the tension right.

Over pressure is trickier.

Panache - 3-12-2011 at 22:33

Quote: Originally posted by Nicodem

Quote: Originally posted by smaerd

Does anyone know if one could use and over-head stirrer type assembly(greased metal bar) through a rubber septum for an air-tight seal? If not is there any cheap quick DIY fix?

Is there a reason balloons seem to be used for these pressure situations and not just the regulator from the cylinder directly?

bbartlog - 4-12-2011 at 05:39

I assume a balloon is used because it can handle overpressures generated within your system (from heat or generated gas). Sometimes reducing the input flow of gas to zero is not enough.

[Edited on 4-12-2011 by bbartlog]

fledarmus - 4-12-2011 at 08:06

Quote: Originally posted by Panache

Is there a reason balloons seem to be used for these pressure situations and not just the regulator from the cylinder directly?

Because they are flexible. If the pressure rises in your system, the balloon expands, if the pressure falls the balloon contracts, and if it goes too far in either direction the balloon breaks. You don't put excessive force on any of your expensive glassware.

querjek - 4-12-2011 at 12:12

Can I make soap from of the greasy runoff from a George Foreman grill?

Ephoton - 27-12-2011 at 01:27

I was wondering if some one could answer a question on butyl lithium reagents.

Sauron posted a quite controvercial Suzuki based synthesis that required the metalation of a halo indole
with tert butyl lithium so as to make the boronic acid.

I belive this was due to the inability of a grignard to form with the halide rather than working with the
indolic nitrogen.

Is it possible to use other lithium reagents for instance the less reactive and less pyrophoric n butyl lithium
for this kind of reaction.

my personal beliefe would be yes but as of yet I have very little working experiance with lithium compounds
other than methyl lithium.

having read a reasonable chunk of the chemistry of organolithium compounds I found that differnt
butyl isomers make for different sites in the molecule being metalated.

would this also be true when a halogen is the target of metalation ?

AndersHoveland - 28-12-2011 at 01:31

Is there any other regent that can substitute for hydrogen iodide HI for selectively reducing ketones?
Something not as harsh as NaBH4, but easier to prepare than AlH3. I read that SH2 is actually a weaker reducing agent than anhydrous HI.

How does PH3 and SiH4 compare?

Squall181 - 3-1-2012 at 17:17

Hi, can someone please help me write a balanced equation for the reaction of lead(II)acetate with sodium bicarbonate which, yields basic lead carbonate(Pb3(OH)2(CO3)2 .

I am having a hard time balancing this reaction I think the hydroxide part of the carbonate is throwing me off. Some guidance will be greatly appreciated.

[Edited on 4-1-2012 by Squall181]

Lead(II) Acetate + Sodium Bicarbonate

Squall181 - 3-1-2012 at 18:20

okay I think I finally figured it out: here's what I got

3Pb(CH3OO)2(aq) + 6NaHCO3(s) --> Pb3(CO3)2(OH)2(s) + 6NaCH3OO(aq) + 4CO2(g) + 2H2O(l)

[Edited on 4-1-2012 by Squall181]

Waffles SS - 10-1-2012 at 11:52

What is standard enthalpy of formation acetic acid,ammonium bicarbonate,ammonium acetate?
I want to calculate enthalpy of this reaction

NH4HCO3 + CH3COOH = CH3COONH4 + CO2 + H2O

Oxygen balance

Adas - 13-1-2012 at 05:53

http://en.wikipedia.org/wiki/Oxygen_balance

Here is oxygen balance calculation accord. to Wikipedia. I have a problem to understand one thing:

Quote:

M = number of atoms of metal (metallic oxide produced).

Is it number of metal atoms or the number of oxide molecules produced?

EDIT: Found out, that the formula is bad (as I expected).
I looked at German Wikipedia and there is the correct formula (I hope), but unfortunately I don't understand it. :X

[Edited on 13-1-2012 by Adas]

Adas - 16-1-2012 at 09:15

Is this possible?

KNO3 + 2 NH3 ----> KN3 + 3 H2O

screamsofsilence - 4-2-2012 at 09:01

Quote: Originally posted by Adas

Is this possible?

KNO3 + 2 NH3 ----> KN3 + 3 H2O

I don't know but if you're only trying to get the KNO3 you could do this; 2 K + 2 NH3 -> 2 KNH2 + H2

2 KNH2 + N2O →-> KN3 + KOH + NH3

stygian - 4-2-2012 at 10:39

Mostly theoretical, a little pondering, but might a poly furfuryl alcohol resin have similar hypergolic reactions as the monomer with nitric acid/derivatives? What sort of science is involved in hypergolic reactions?

entropy51 - 4-2-2012 at 14:00

Quote: Originally posted by Adas

Is this possible?

KNO3 + 2 NH3 ----> KN3 + 3 H2O

No. Are you one of those people who thinks that any equation that can be balanced is possible? I sure hope not.

watson.fawkes - 4-2-2012 at 16:45

Quote: Originally posted by entropy51

Are you one of those people who thinks that any equation that can be balanced is possible? I sure hope not.

He forgot to write it with the proper reaction conditions:
KNO3 + 2 NH3 ----magic----> KN3 + 3 H2O

entropy51 - 4-2-2012 at 16:50

Quote: Originally posted by watson.fawkes

[KNO3 + 2 NH3 ----magic----> KN3 + 3 H2O

Have you noticed that we have had a huge influx of wizards recently? The amount of magic is absolutely breathtaking!

solo - 8-2-2012 at 16:31

"Preparation of Ethylenediammonium diacetate (EDDA)
A 150 ml beaker, containing 100 ml dry ether and 12.0 g (0.2 mol) of ethylenediamine, is placed in an ice-bath and a solution of 24.0 g (0.4 mol) glacial acetic acid in 20 ml ether is added with stirring at such a rate as to prevent boiling of the ether. The solution is left to crystallize overnight, then filtered with suction, the crystals washed with ether and recrystallized from approximately 50 ml MeOH. Yield after drying in a vacuum desiccator is around 27.5g (75%) of colorless needles, mp 114°C."

......source,

http://www.erowid.org/archive/rhodium/chemistry/edda.html

......i've tried this process to the letter and the product has a low MP 75 C.....any idea why the material turns pasty while the addition of the ether/GAA, even though i have it stirring.....maybe the magnetic stirrer isn't sufficient and need to use overhead stirrer....any thoughts, from someone familiar with the synthesis?.......solo

solo - 8-2-2012 at 16:43

I found this over at Hyperlab, it may provide the answer......

Practical test methods for the synthesis
ethylenediamine (etilendiammoniya) diacetate.

Some time ago, someone won a
of 50% ethylenediamine grade B, dostatogo for free.
But from it we can make a useful substance, he thought.
And, indeed, the substance is called ethylene diamine diacetate
used as a mild and efficient
catalyst for the condensation reatsy various aldehydes
and nitroalkanes. Otherwise known as Henry reaction (Henry reaction).

The first source was the synthesis of the recipe with a friend of his L.Tittse T.Ayherom.
It was decided to do what they recommend. But it was nevertheless
viewed
Alternatively, the site of synthesis of rhodium. But a glance at and
noting that the mass of the reagents used are the same here and there, completely
transfer method did not. And in vain ...

L.Tittse, T.Ayher
"Physical Organic Chemistry," page 468
http://chemister.da.ru/Books/Chembooks/Pra...ikum/Titce.djvu

P-3a Etilendiammoniya diacetate.

CH3COOHH2N-CH2-CH2-NH2 ---------> H3N-CH2-CH2-NH3 * 2CH3COO-60.1 60.1 180.2
Reaction. The formation of ammonium salts of the free amine and acid.
Etilendiammoniya diacetate is a gentle and effective
catalyst for the interaction of CH-acidic compounds
with carbonyl groups (pH 7 in water).

To a solution of 12.0 g (0.20 mol) of ethylenediamine in 100 ml of anhydrous
ether was added dropwise with stirring 24.0 g (0.4 mol) of acetic
acid in 20 ml of ether, and then left for 14 hours in the refrigerator.

The precipitated crystals were filtered, washed with ether and
recrystallized from 50 ml of MeOH, to give 19.8 g (83%) of salt
as colorless crystals, mp. 114 ° C

I must say that this recipe, at least one typo:
not "give 19.8 g (83%) of salt," and "receiving 29.8 g (82.7%) of salt."
And a lack of understanding: to cool the mixture in an ice bath
the addition of acidñ.

https://www.rhodium.ws/chemistry/edda.html
Preparation of Ethylenediammonium diacetate (EDDA)

A 150 ml beaker, containing 100 ml dry ether and 12.0 g (0.2 mol)
of ethylenediamine, is placed in an ice-bath and a solution of 24.0 g (0.4 mol)
glacial acetic acid in 20 ml ether is added with stirring at such a rate as to
prevent boiling of the ether. The solution is left to crystallize vernight,
then filtered with suction, the crystals washed with ether and recrystallized
from approximately 50 ml MeOH. Yield after drying in a vacuum desiccator is
around 27.5g (75%) of colorless needles, mp 114 ° C.

In 150 ml glass of the chemical placed in an ice bath containing
100 ml of dry ether and 12.0 g (0.2 mol) of ethylenediamine was added at
stirred solution of 24.0 g (0.4 mol) of glacial acetic acid in 20 ml
ether
at such a rate as to prevent boiling of the ether. The solution was allowed to stand
night
for crystallization and then filtered with suction. The crystals were washed
ether and recrystallized from approximately 50 ml of methyl
alcohol.
The yield, after drying in a vacuum desiccator, is about 27.5 g (75%)
colorless crystalline needles with a melting point of 114 ° C

In this recipe the volume of the cup is completely filled with a mixture
which is inconvenient. Shed easily.

Description of the synthesis.
In a 250 mL conical flask with a wide mouth (29) was weighed clean
ethylenediamine in an amount of 12.0 g (0.2 mol) and mixed with 100 ml
dehydrated
ether (dried calcined alumina produced, about 10 g per 100
ml)
In another small flask weighed 24.0 g (0.4 mol) of glacial
acetic acid and diluted with 20 mL of ether.
With the help of a pipette 10 ml acid solution in ether was added slowly
to a solution of the amine and the mixture shaken.
The reaction is exothermic, stand a pair of white.

Since the synthesis was planned for the recipe and L.Tittse T.Ayhera, the cooling
reatsionnoy mixture did not care, so the flask was cooled from time to time
in the freezer without giving the airwaves to a rolling boil.

Almost immediately after the addition of the first portions of acid, a white
tight
precipitate, which was stirred and loosened with a glass rod.
After the addition of acetic acid formed a rich, white,
crystalline precipitate, like powdered sugar. But in some places
fused in clumps, as well as adhering to the walls of the flask.
All this mess scraped from the walls and crush glass
stick.

Using this method a conical flask Eylenmeyera optimally
as
work with such a deposit in the round (flat) bottom is very inconvenient. A Chem.
glass
plug does not shut up. For those who like to work glasses, it is better to take
amount of not less than 250 ml. Since the 150 ml beaker chemistry, the recommended
Website Rodia simply too small for normal operation.

Following the procedure, the bulb with the precipitate in ether was left overnight in
the refrigerator.
The next day, visually, the precipitate in the flask is not increased. Therefore, the
the need for long standing in the cold on the issue.

Remembering all the essential gemmoroynost vacuum filtration solutions
it was decided to abandon it. A carefully and completely drain the air with
precipitate and wash it several times with ether in portions of 50 ml.

Further, in the same vessel, the precipitate was dried at 50-60 degrees in the oven to
complete dryness, stirring occasionally, and eventually became similar to
baby food.

Recrystallization was carried out from methyl alcohol, a gradual
its addition to the powder in a water bath. Results for the full
dissolution of the precipitate, it took 45 ml of alcohol.

The hot clear solution was poured in a dish on which is in
hot
water, and then, with this water is cooled slowly, periodically
stirring.
After some time, drop a small, colorless, transparent
crystals.
For a more complete separation of crystals placed a cup in the refrigerator for
a few hours. After that, the mother liquor was drained and the crystals rapidly
pressed on the cooled glass filter.

The resulting product was dried in a desiccator under vacuum at first, after standing
in sulfuric acid until the weight change.

The yield is 28.3 g (78%) of transparent yellowish crystals
with a melting point of about 113 ° C
Subsequently, while cooling the mother liquor in the freezer, dropped
about 4 grams of crystals.

Drying of ethylenediamine.
Ethylenediamine (1,2-diaminoethane) H2N-CH2-CH2-NH2
Mol. weight of 60.100 - a colorless liquid with ammonia odor;
mp. 8,5 ° C, bp. 117,0 ° C; 62,5 ° C (100 mm Hg. Art.)
Miscible with water, alcohol, acetone, benzene, ether;
poorly soluble in n-heptane.
Forms azeotropic mixtures with water: hydrate, ethylenediamine C2H8N2 * H20
mp. 11 ° C, bp. 118,5 ° C;
with toluene, bp. 103 ° C, 30% ethylenediamine
a cellosolve, bp. 130 ° C, 31-32% ethylene diamine
(Brief Chemical Encyclopedia)

As already mentioned, in the presence of 50% of the present solution and the reaction
required anhydrous ethylenediamine.

On the advice of friends (Angel, respect!) Was employed method
salting out.
After trying on a small amount of amine this method, and making sure it
applicability, it was decided to move it to the big boot.

300 g of the amine solution are placed in half-liter bottle of chemicals.
Chem dishes like funnel, etc. it was a pity,
because of the ravages of hot conc. alkali.

The solution was shaken with small amounts of alkali NaOH
(Noticeably 30-40 g) to form a saturated alkaline
solution, followed by standing and separation of the layers.
After that, the bottom layer of liquor pulled the 20 cc syringe.
After the third division of NaOH no longer dissolved, and it was
decided to heat the mixture on a water bath, repeating the same procedure.
It was a success, and it should be noted, when heated
salting out and separation of the layers is much faster.

Thus, the last portion of the total alkali, 200 grams
load does not dissolve completely even after long heating,
about two hours, and periodic shaking.

Shit! No need to use the bottle rocket.
Female cracked right in the bath! Well, not that the bottom has dropped out, and
amine failed to save. It is necessary to use a heat-resistant container.

When he came to the conclusion that a good idea, to begin to overtake on the recommended
method,
azeotrope with the garbage, it was decided to clarify the boiling point of substances.

And what is revealed:

Ethylenediamine bp. 117.0
Ethylenediamine hydrate, bp. 118.5 (760 mm)

It's fucking reverse azeotrope, so even with minimal
temperature difference.

With the help of a thermometer available, hardly will be fixed
such a small difference.

Therefore, the distillation has been postponed until further and decided to
drier according to the method recommended by Katznelson.
That is, drying in a closed bank on fused alkali at 100 degrees
throughout, though, would be 10-12 hours of oven.
And then drive away the amine, discarding the first and last fractions.

That was done. After drying, alkali cakes have hardly changed
and fun rolled into an anime. This indicates that the water in it
is almost gone. Ethylenediamine distilled into three unequal parts, for
synthesis was used the average (the largest) fraction.

Alastair - 21-2-2012 at 10:10

Can anyone explain me the amalgamation process? I understand it activates metals and removes oxide coating. But what happens to Hg or mercury salts? A short example with sodium or aluminium would help alot, because im curious about this process. Thank you.

AndersHoveland - 21-2-2012 at 12:40

What is the actual reaction between dihydroxyacetone and ammonia?
I have tried searching for the answer online, and apparently the reaction is very complicated.

One source suggests that pyrazine derivitives form.
http://onlinelibrary.wiley.com/doi/10.1002/1097-0010(200006)80:8%3C1262::AID-JSFA634%3E3.0.CO;2-T/full

I also know that bromoacetone reacts with NH3 to make 3,6-dimethyl-2,4-dihydropyrazine, C6H10N2.

[Edited on 21-2-2012 by AndersHoveland]

plante1999 - 25-2-2012 at 14:49

Does Magnesium chlorate is solube in methanol? I want to synthesise it from KClO3 and MgSO4, I thinked to boil a mixture of KClO3 and MgSO4 in methanol but I dont know if Magnesium chlorate is solube in Methanol.

Thanks!!!

bbartlog - 2-3-2012 at 18:34

If I mix a solution of sodium carbonate (containing three equivalents of sodium ions) with one equivalent of phosphoric acid, and heat the resulting solution, what is the result? Does all the carbonate eventually get driven off as CO2, yielding a basic solution of Na3PO4? Or does some CO2 get held in solution by the rather basic Na3PO4?

manimal - 4-3-2012 at 20:08

Hi,

What is the correct stopper size for a flask of dimension 24/40?

Mik229 - 5-3-2012 at 05:58

Hello

What will be the product from reaction between primary amine and grignard reagent?

AndersHoveland - 5-3-2012 at 13:14

Is it possible to isolate tetramethylammonium methoxide?
Is this compound a liquid?

If it is a liquid, I am sure it would be a very dangerously corrossive substance, much more caustic than sodium hydroxide.
Could this have application for dissolving certain metals that are resistant to acid?

bbartlog - 6-3-2012 at 17:53

Quote: Originally posted by manimal

Hi,

What is the correct stopper size for a flask of dimension 24/40?

I believe a #4 stopper should work reasonably well for a 24/40 female glass joint.

bbartlog - 6-3-2012 at 18:05

Quote: Originally posted by plante1999

Does Magnesium chlorate is solube in methanol? I want to synthesise it from KClO3 and MgSO4, I thinked to boil a mixture of KClO3 and MgSO4 in methanol but I dont know if Magnesium chlorate is solube in Methanol.
Thanks!!!

Old references say magnesium chlorate is soluble in alcohol (also acetone). Potassium chlorate on the other hand really isn't, much... likewise MgSO4 is only sparingly soluble. Sounds like it would be a better way to get to KClO3 from MgClO3 than the other way around.

plante1999 - 6-3-2012 at 18:19

Quote: Originally posted by bbartlog

Quote: Originally posted by plante1999

Thanks! In fact I think the reaction is favorable since one of the product is soluble and the two reactant are sparingly solube.

Endimion17 - 9-3-2012 at 08:04

Is white phosphorus soluble in ethanol? I need that info ASAP, and don't have the time to search for it. Thanks.
(I'm not experimenting with it, just writing an article)

barley81 - 9-3-2012 at 08:29

Yes.
<a href="http://books.google.com/books?id=CXinC8gW6BEC&pg=PA334&lpg=PA334&dq=white+phosphorus+solubility+table+ethanol&source=bl&ots= XrOCfOcEPY&sig=pZnmlMvlEnSzLw0mB9ZcsSo_kx4&hl=en&sa=X&ei=VS9aT8_qAuHY0QGTvoCtDw&ved=0CFAQ6AEwBg#v=onepage&q&f=false">Re ference</a>

Endimion17 - 9-3-2012 at 09:02

Thanks! I supposed it was, though much less than in carbon disulphide. If you happen to stumble upon an exact value, I'll appreciate it.

benzeentje - 20-3-2012 at 10:45

Hi all, i'm trying to extract caffeine without chloroform or other halogen-alkanes. I have thinner (mostly toluene), terpentine, and white spirit. Wich one is best, considering this caffeine doesnt need to be edible?

I was thinking thinner (because of the toluene) but it has a boiling point of +-110°C -.-

Adas - 20-3-2012 at 10:53

Quote: Originally posted by benzeentje

Hi all, i'm trying to extract caffeine without chloroform or other halogen-alkanes. I have thinner (mostly toluene), terpentine, and white spirit. Wich one is best, considering this caffeine doesnt need to be edible?

I was thinking thinner (because of the toluene) but it has a boiling point of +-110°C -.-

Why not to use ether?

Pages: 1 2 3 4 5 6 .. 8