(Hive Addict)
02-05-03 08:19
No 404741
(Rated as: excellent)
Patent US4499300
This patent describes cobalt (II) catalyzed oxidation of readily available 1,4-diethylbenzene to p-Et-acetophenone, but can be addapted to suit own needs.
Oxidations were performed in a 50 ml flask fitted with a bottom-sealed sintered disc to effect air dispersion, a condenser, and a Dean-Stark trap. The flask was charged with 10 grams of 1,4-diethylbenzene while air flowed through the sintered disc at a rate between 125 and 250 cc per minute. The cobalt compound used as a catalyst was added, and the contents heated to the desired temperature. Samples were withdrawn periodically and analyzed by gas-liquid chromatography to afford the results summarized in Table 1. The product, 4-ethyl acetophenone, was then isolated by the fractional vacuum distillation of the oxidation product mixture [...]
Consult the above patent for the details
Accept No Imitations, There Can Only Bee One; www.the-hive.ws
(Hive Addict)
02-05-03 10:43
No 404772
(Rated as: excellent)
(patent was consulted for details...)
US Patent 4499300
4-Vinylbenzeneacetic Acid
Abstract:
A multi-step preparation of 4-vinylbenzeneacetic acid from the readily available 1,4-diethylbenzene is described. The method uses cobalt (II) catalyzed oxidation of 1,4-diethylbenzene to 4-ethylacetophenone followed by oxidative rearrangement of the latter to 4-ethylbenzeneacetic acid, selective photochlorination, and finally base catalyzed dehydrochlorination of the latter to afford the title compound.
Example 1:
Oxidations were performed in a 50 ml flask fitted with a bottom-sealed sintered disk to effect air dispersion, a condensor, and a Dean-Stark trap. The flask was charged with 10g of 1,4-diethylbenzene while air flowed through the sintered disk at a rate between 125-250cc/minute. The cobalt compound used as a catalyst was added, and the contents heated to the desired temperature. Samples were withdrawn periodically and analyzed by gas-liquid chromatography to afford results in Table 1. The product, 4-ethyl acetophenone, was then isolated by the fractional vacuum distillation of the oxidation product mixture prior to its use as a reactant in the step.
Table 1:
Co(acetylacetate)2, 0.19 mol %, 105-110*C, 6hr, 38% conversion, 61% selectivity
0.19 mol %, 105-110*C, 16hr, 68% conversion, 63% selectivity
Co(neodecanoate)2, 0.19 mol %, 110-115*C, 6 hr, 49% conversion, 83% selectivity
Co(stearate)2, 0.19 mol %, 110-115*C, 9.5 hr, 73% conversion, 79% selectivity
Co(naphthenate)2, 0.26 mol %, 120*C, 6hr, 78% conversion, 72% selectivity
0.26 mol %, 120*C, 7 hr, 80% conversion, 68% selectivity
Co(toluenesulfonate)2, 3.00mol %, 90*C, 4 hr, 94% conversion, 44% selectivity
3.00mol %, 120*C, 2 hr, 0% conversion, 0% selectivity
Co(phthalocyanine)2, 0.26 mol %, 120*C, 2 hr, 26% conversion, 81% selectivity
0.26mol %, 120*C, 5 hr, 26% conversion, 81% selectivity
Example 2:
Preparation of 4-ethylbenzeneacetic acid
A 300ml ,3-neck flask with mechanical stirring, condensor, dropping funnel and Dean-Stark trap was charged with 66.9g (0.45mol) of 4-ethylacetophenone, 62.1g (0.71mol) of morpholine, and 22.8g (0.71mol) of sulfur. The contents were heated to 135-140*C under nitrogen, in some cases with removal of water. After about 3 hours, the mixture was cooled to about 40*C and about 120g of 20% aqueous sodium hydroxide was added with stirring. This mix was then heated to reflux and stirred for about 9 hours. After the reaction mix was cooled some of the morpholine and water were distilled off at 90-100Torr. To the residue at 60*C, was added slowly with stirring 50ml of conc. HCl acid brought to boiling and the hot reaction mass was stirred for about 1 hour. The solid, which is a mix of mainly the formed acid and sulfur, was collected with a 15% aqueous solution of sodium bicarbonate. The filtrate was then heated to boiling, decolorized with carbon, filtered and repeated. The solid was washed with hot water and the combined filtrates were acidified with conc. HCl acid to precipitate the 4-ethylbenzeneacetic acid. Without water removal in the reaction, 65% yield of the product is obtained and 100% of the morpholine can be recovered. Whereas, without the removal of water in the reaction, a 72% yield of the product is obtained and 0% of the morphonline can be recovered.
Example 3:
Preparation of 4-(1’-chloroethyl)-benzeneacetic acid
A solution of 4-ethylbenzeneacetic acid in either carbon tetrachloride or chloroform was reacted with chlorine while being irradiated with ultraviolet light.
Sample A: 0.01 mol reactant, 0.01 mol Cl2,15ml CCl4, 0.33 hr, 50% conversion, 100% selectivity
Sample B: 0.04 mol reactant, 0.04 mol Cl2, 70ml CCl4, 0.33 hr, 64% conversion, 80% selectivity
Sample C: 0.183 mol reactant, 0.19 mol Cl2, 200ml CHCl3, 1.25 hr, 52% conversion, 100% selectivity
Sample D: (Sample 3 continued for another 0.19m Cl2) 0.38 mol Cl2
Note: Selectivity of monochlorination at the benzylic carbon of the ethyl group is quantitative up to about 50%
Example 4:
Dehydrochlorination of 4-(1’-chloroethyl)-benzeneacetic acid
To a solution of 4-(1’-chloroethyl)-benzeneacetic acid in methanol may be added about 5 molar portions of sodium methoxide. The mix is stirred with gentle heat (about 50*C) for several hours. The cooled solution may then be acidified with a slight excess of 5% aq. HCl acid and extracted with ether to give the product, 4-vinylbenzeneacetic acid.
References Cited:
US Patent 4362891
(Hive Addict)
02-05-03 10:44
No 404773
Maybe for ethylbenzene to PAA?
Acetophenones?
Propiophenones?
(Hive Addict)
02-05-03 14:15
No 404822
I think that I posted the patent # before... but OK, I'm not the one rating the posts...
Accept No Imitations, There Can Only Bee One; www.the-hive.ws
(Hive Addict)
02-05-03 14:23
No 404824
the credit wasn't given for finding the patent, it was for the effort put forth in typing it. but, aurelius agrees- you should also get an "excellent"
(Hive Bee)
02-05-03 14:25
No 404825
Karma fight ;)
Abusus non tollit usum
(Chief Bee)
02-05-03 15:51
No 404843
Yes, typing up a patent (or OCR'ing it) into ASCII is in my opinion worth much more than simply finding it, as immensely more information is to be found in the post if the relevant sections of an article is included, rather than just being a link to a patent or article somewhere, that's why I always try to post typographically correct transcriptions instead of just linking to patents/articles, see Post 400040 (Rhodium: "P2P by Grignard Addition to Acetic Anhydride", Novel Discourse) or Post 401290 (Rhodium: "Synthesis of Derivatives of Myristicin", Novel Discourse).
(You may have noticed that PolytheneSam does not have very many karma points despite finding hundreds of good references all the time, and that is because he usually only links to patents with minimal description of what they describe, so to be able to find out if they are good or not (and sometimes even to find out what they are ABOUT) you need to follow the link and read through perhaps several pages for each link - that takes too much time for everyone, a lot of work would be saved if summaries were posted for each link).
My personal karma point rating guidelines (rough sketch):
Posting general unreferenced information: No karma
Posting detailed, useful unreferenced information: May give karma if useful/novel enough, as in Post 293689 (Ritter: "MDP1P", Chemistry Discourse)
Finding a good article, linking to it: Usually no karma, except in special cases, like Post 367468 (Regis: "The most interesting CTH reaction ever documented?", Novel Discourse)
Finding a good article, linking to it and writing a nice summary: Usually gets a karma point, like Post 380478 (pHarmacist: "p-F-benzaldehyde from p-Cl-benzaldehyde", Methods Discourse)
Posting an article, but without including a summary: Usually no karma (as it is not obvious what its good for), like Post 398805 (Aurelius: "US patent 3197473", General Discourse) (which got a karma point first AFTER it was explained)
Finding a good article, posting it [b]and writing a nice summary:[/b] Always gets a karma point, like Post 401843 (Antoncho: "The easiest PhCOOH -> PhCHO reduction yet!", Novel Discourse)
Writing a review (posting good articles with comments): Always gets a karma point, like Post 380385 (Chimimanie: "from p-toluic acid to 3-Meo-4-methyl-amphetamine", Methods Discourse)
Performing a novel experiment and posting detailed results: Always gets a karma point, like Post 400849 (geezmeister: "Phosphorous Acid Works", Stimulants)
(Hive Addict)
02-05-03 20:22
No 404934
Hey Rhodium, nice tact! going a round about way to put everybody's name in there, how cute
it is nice to have guidelines though. Perhaps we should develop a general format that can be referenced? as changes are made the thread that it's in will move back to the top of the thread so everybody will see them as they are made. (Hive Addict)
02-06-03 04:22
No 405069
What do you meen typing? Ever heard about copy/paste? Besides, some bees are simply puting out patent numbers when making a post and get karma point, PolytheneSam is a good example, he often just puts out patent numbers and you seem to have missed him when giving examples; Post 346235 (PolytheneSam: "Post 18563", Methods Discourse) I guess next time I shuold copy the whole patent text and paste it...
Yes, typing up a patent (or OCR'ing it) into ASCII is in my opinion worth much more than simply finding it...
Yes, but without bringing the relevant information to the attention of Hive there would be nothing for Aurelius to "type".
Besides, in the patent of this thread only the acetophenone is of interst, further manipulations are compleatly uninteresting in my opinion...
Accept No Imitations, There Can Only Bee One; www.the-hive.ws
(Hive Bee)
02-06-03 05:12
No 405077
I wonder, whats the big deal about those karma points. The main objective here is to beat the narcs. Keep up the good work, don't compete with one another.
(Hive Addict)
02-06-03 05:17
No 405078
Oh, I was just offended by this, I know what the main objective is, but I still have the right to speek up if I feel that something is un-fair, right? I'm not going to get discoureged from posting even if I never get any karma points, but somebody else might be...
Accept No Imitations, There Can Only Bee One; www.the-hive.ws
(Chief Bee)
02-06-03 06:40
No 405086
Pharmacist: Please do not copy/paste entire patent texts, limit yourself to only post the relevant parts, and preferably with nice typography using markup code.
(Hive Addict)
02-06-03 11:52
No 405178
Ok, here's a question for the crowd. Does everybody feel the same way as pHarmacist does about aurelius' "work"? Is it generally felt to be a waste of time? aurelius isn't doing this for the fun of it. if nobody appreciates the work, then aurelius would be glad to stop and do research and work in other areas that are more pressing to aurelius' own interests. Concensus?
(Hive Addict)
02-06-03 12:00
No 405182
I have nothing against what you do. I have never said that. Keep up. I just want credit for what _I_ do... Karma might sound as something unimportnant but why do we have it then?
Accept No Imitations, There Can Only Bee One; www.the-hive.ws
(Chief Bee)
02-06-03 12:15
No 405184
We have it so that it will be easy to find the top 1% posts here at the Hive, so that people in general does not have to read each and every post made to find the best stuff. As you know, it is possible to UTFSE for only "excellent" posts. The accumulated karma is also a help for newbies to see which users are the most reliable information-wise.
(Hive Addict)
02-06-03 12:44
No 405195
Hey pHarmacist, aurelius didn't take offense at the comment. aurelius just wanted to know if aurelius had been wasting precious time with something that no one cared about. however, aurelius has already received enough positive feedback to show that simply isn't true. and yes, aurelius does still believe that you deserve an "excellent" rating. (as stated previously)
(Chief Bee)
02-06-03 13:10
No 405205
Pharmacist: You have also gotten a karma point, for the sake of justice. Your post would have been rated automatically if Aurelius hadn't posted the rest below.
Aurelius: Do you think you can remember to always post a summary/explanation of your transcriptions in the future?
(Hive Addict)
02-06-03 14:31
No 405231
Sure. i'll try anyway. it's kinda hard to remember everything when doing things as quickly as possible.