n00bz (Stranger)
04-29-03 01:38
No 430071
      OTC solvent purity levels / How to clean  Bookmark   

After months of preparatory reading, SWIM is ready to practice some of the basics involved. Wanting to start out on something easy, SWIM chose to practice drying of solvents and some basic purification techniques. After a trip to the colored roof’s, SWIM came across some pretty useful stuff and decided to do more research. This is what was found:

Xylene that is labeled 100% pure however according to the MSDS contains 80-85% Xylene and 15-20% Ethyl Benzene.

91% Isopropyl Alcohol, 9% water

Acetone labeled 100% pure, MSDS states 95-100% Acetone, 5% water assumed but not stated.

Now after some more research and several hours with TFSE, SWIM came to the conclusion that a great many bee could be using the same products, but no information was ever mentioned about if purification was possible or necessary. SWIM figured that Ethyl Benzene was probably not a good thing to have so he wanted to remove it via distillation. After getting the BP of both Xylene (140C, insoluble in H20) and Ethyl Benzene (136.2C, insoluble in H20), distillation was out of the question (BP’s are within 20 C of each other, can not use simple distillation SWIM read someplace). The bottom line is, does SWIM need to be concerned about the Ethyl Benzene present, or can he just dry the Xylene with MgS04 and be done with it.

If SWIM dries the Isopropyl with MgSO4, he assumes that should leave him with 98-99% Isopropyl

Please forgive the length of post for such a simple question. SWIM spent several hours with TFSE and GOOgLe that only left the above questions unanswered. SWIM understands that these materials are available in pure from chem suppliers, however, given the current state of the union, SWIM wants to avoid talking to anyone who doesn’t have a name tag with a major corporate logo on it.

Any suggestions of links to helpful information are appreciated!

I learn to better myself
(Hive Bee)
04-29-03 18:39
No 430222
      Ethylbenzene  Bookmark   

Ethylbenzene may sound rather nasty, probably because it's name includes the dreaded 'benzene' with it's carcinogenic associations and the like, but would it comfort you to tell you an alternative name for toluene is methylbenzene, and xylene is also called dimethylbenzene?

Probably not, but the point is, I seriously doubt that any reaction you are planning on using xylene as a solvent for will be affected by the contamination of 15-20% ethylbenzene, or any other amount of ethylbenzene for that matter. It may still be helpful to distill your solvents before use anyway however; of course it won't separate the xylene/ethylbenzene mixture, but it will leave behind any higher boiling point impurities which may be present in non-lab grade solvents. Distilling cheap solvents is also a good way to learn so you don't mess up when it comes to distilling more 'important' reagents.
04-30-03 03:04
No 430302
      Thanks for the info. SWIM went on chemfinder...  Bookmark   

Thanks for the info. SWIM went on chemfinder and noticed in the synonyms entry for Xylene “Xylene mixture (60% m-xylene, 9% o-xylene, 14% p-xylene, 17% ethylbenzene)”. SWIM will definitely practice distilling when the time comes

I learn to better myself
05-07-03 13:08
No 431909
      Info About Aromatics  Bookmark   

Four important aromatic hydrocarbons are benzene, toluene, xylene, and styrene.  Benzene has the basic ring structure that the rest of the hydrocarbons are constructed around.  It is considered to be a carcinogen so I wouldn't recommend playing around with it. Toluene is methylbenzene which says that it is benzene with a methyl radical attached.  The fact that it only has one radical is what makes this the fastest evaporating, best de-gunker for chemical extraction and washing.  Toluene is not yet considered to be a carcinogen but is still some pretty nasty stuff so be careful. Xylene is, yes, dimethylbenzene which says that it is benzene with two methyl radicals. This creates the posibility of three isomers: ortho, meta, and para xylene (depending on where the second radical is located compared to the first around the benzene ring). This is a good alternative to toluene but is slower at evaporating and does less de-gunking. Xylene is not considered to be carcinogenous. Styrene is something I don't feel the need to get into.  It is reactive and doesn't serve much purpose in chemical extraction or cleaning, as it has the tendency to alter chemicals' structure.  Phenylethane is what you've referred to as ethylbenzene which says that it is benzene with an ethyl radical. An ethyl radical is different from a methyl radical because it has two carbons on it's branch as opposed to methyl's one carbon. Having this in a xylene mixture will not negatively affect extraction or washing.

Don't ask me why I gave so much information.  I just started writing and couldn't stop.  Somebody might find this info useful.  Who knows . . .

Dr. Nasty