The Vespiary

The Hive => Newbee Forum => Topic started by: ning on August 24, 2003, 09:24:00 AM

Title: How to make chlorobenzene
Post by: ning on August 24, 2003, 09:24:00 AM
I am sorry, I thought I saw a document on how to make chlorobenzene around here, but neither of TFSE's seem to have any info.

Referencing "Benzyl Chloride Synthesis by madchemist", it seems one can create chlorine ions in solution with HCl and NaOCl...this may work for toluene, but can they chlorinate a benzene ring?

Anyway, I know this is a bit of a triviality, but I hope someone can find it in their vast wisdom and endless patience to point me to a high-yielding, completely OTC synthesis  ;) (complete with photos, if you please) ;)

Or just some references to chase would be nice too....

Title: i couldn't find anything on it either
Post by: StraightEdge on August 25, 2003, 07:03:00 AM
I think the reason is that there is little interest in making it. It is not a watched chemical.

Nonetheless, here is what it says in the Merck:
"Produced by the chlorination of benzene in the presence of a catalyst.  Review of manuf, properties, and use:  Faith, Keyes & Clark's Industrial Chemicals, F. A. Lowenheim, M. K. Moran, Eds. (Wiley-Interscience, New York, 4th ed., 1975) pp 258-265."

When you reference a post, you should give the post number inside these characters: [ ]. That way people can see what you are referencing without havign to search for it.
Title: Chlorobenzene
Post by: Mountain_Girl on August 25, 2003, 04:06:00 PM


Chlorination of benzene

Benzene does not react with chlorine unless a Lewis acid such as ferric chloride is present in the reaction mixture. The reaction is exothermic and the product is the result of substitution rather than addition where chlorobenzene is given in good yield.
           
          FeCl3         
C6H6 + Cl2 __> C6H5Cl + HCl
                               
Although the reaction takes place at room temperature, it does not go to completion. The chlorination of benzene is generally carried out at 57°C to ensure 100% conversion.
The introduction of a chlorine atom deactivates the ring somewhat towards further attack. However, this is not sufficient to prevent polyubstitution, and depending on the amount of chlorine present, di-, tri- and higher chlorobenzenes are formed. In order to minimise polysubstitution, excessive temperatures are avoided and the mono product is removed from the reaction zone as soon as it is formed.

Alumina (Al2O3) has been used as a catalyst industrially.



References unknown.

Also check:

Patent US3226447 (http://l2.espacenet.com/dips/viewer?PN=US3226447&CY=gb&LG=en&DB=EPD)


Patent US1946040 (http://l2.espacenet.com/dips/viewer?PN=US1946040&CY=gb&LG=en&DB=EPD)


Patent BP388818 (http://l2.espacenet.com/dips/viewer?PN=BP388818&CY=gb&LG=en&DB=EPD)


Patent US2976330 (http://l2.espacenet.com/dips/viewer?PN=US2976330&CY=gb&LG=en&DB=EPD)


Patent US3636171 (http://l2.espacenet.com/dips/viewer?PN=US3636171&CY=gb&LG=en&DB=EPD)


Patent US3557227 (http://l2.espacenet.com/dips/viewer?PN=US3557227&CY=gb&LG=en&DB=EPD)


Patent US2826617 (http://l2.espacenet.com/dips/viewer?PN=US2826617&CY=gb&LG=en&DB=EPD)


Patent US2943114 (http://l2.espacenet.com/dips/viewer?PN=US2943114&CY=gb&LG=en&DB=EPD)


Patent US2886605 (http://l2.espacenet.com/dips/viewer?PN=US2886605&CY=gb&LG=en&DB=EPD)


Patent US2866828 (http://l2.espacenet.com/dips/viewer?PN=US2866828&CY=gb&LG=en&DB=EPD)


Patent US2949491 (http://l2.espacenet.com/dips/viewer?PN=US2949491&CY=gb&LG=en&DB=EPD)


Patent US2666085 (http://l2.espacenet.com/dips/viewer?PN=US2666085&CY=gb&LG=en&DB=EPD)


Patent US2819321 (http://l2.espacenet.com/dips/viewer?PN=US2819321&CY=gb&LG=en&DB=EPD)


Patent US2920109 (http://l2.espacenet.com/dips/viewer?PN=US2920109&CY=gb&LG=en&DB=EPD)





Title: Ahhh, yes...
Post by: ning on August 26, 2003, 05:45:00 AM
Just like the bromo and iodobenzene sytheses, right? Hah. Should've figured. Well, I'll be getting a copy of the merck soon. Thanks, guys. You're right about just buying the stuff, but I was really hoping to put together a completely otc synthesis that could be large-scaled (unlike RP/I ephedrine). I just wish I could find some otc benzene, cuz that's really the sticking point. This could be considered a "stealth synthesis", because if everything is otc in large quantities, there would be no need to get anything mailed, no need for any front companies, nuthin. Looks good so far.

By the way, thanks for the tip on referencing posts. I was rather wondering about that.