Catalytic Hydrogenation Mechanism 1

[Sheriff007]

Hello. My name is Aditya Persaud, and i'm designing a chemical plant to manufacture commercial margarine from sunflower seeds. I'm in dire need of the Reaction Kinetics and mechanism governing the Nickel-catalyzed hydrogenation of sunflower oil. I would greatly appreciate any help that is offered. Thank you very much in advance.

 

[monch]

Hello Aditya:
My name is David and I would like to help you because I´m designing a plant of margarine too.
I found this message looking for information about the kinetic reaction about the hydrogenation of sunflower oil.
You can see that I have the same problem like you.
This information is very difficult to find, because I´m seraching in a lot of places but I find nothig.
I´d like to contact with you and search together information and transfer information.
Thanks.
PD: Sorry my english, but I´m spanish.
My e-mail: monch500@hotmail.com

 

[bchoate]

bchoate
There is information available if an appropriate search engine is used. Scientific and engineering literature can be searched using

http://www.scirus.com.

The engine will search both the web and journals and you can select which set of hits are presented. Click the advanced search button and make the following entries: top blank = sunflower oil;
bottom blank = hydrogenation. Click search at bottom of page.
There is a journal article about the kinetics:
Chemical Engineering Science, Vol 34(8), 1979, 1051-1056.
This is an Elseveir publication. You will have to find it in a library or use a Science Direct account. There are other articles that may be of interest in the search above.
If you use a CSTR as the hydrogenation reactor, an anchor agitator gives higher gas (hydrogen) hold up.
Nickel on kieselguhr or nickel on diatomite (0.33% wt) are catalysts for this reaction. Calsicat, a division of Engelhard, produces catalysts for the fatty oil industry.
Bill C.

 

[moltenmetal]

I know nothing about current practice with respect to hydrogenation of vegetable oils. I have a dusty recollection of the use of "Rainey Nickel" (a special type of nickel sponge) for this application, or at least that's what the catalysis prof told us years ago... Is that still done, or have they switched to supported nickel catalysts as bchoate indicates?

 

[bchoate]

bchoate
"Rainey nickel" is a catalyst prepared from a nickel/aluminum alloy in which the aluminum is removed by selective dissolution. Rainey copper and rainey cobalt are prepared similarly. Rainey nickel has a wide range of industrial applications such as hydrogenation, dehydrogenation, ammonolysis, and reductive alkylations. It is often used in the reduction of aldehydes or ketones, nitro compounds, nitriles, and olefins or alkynes. The hydrogenation is a 3 phase process conducted in a CSTR. Hydrogen loading (holdup) in the liquid phase is critical to yield and selectivity. Rainey nickel catalyst are not typically used for fatty oil hydrogenation for margarine.

The typical catalyst used in the margarine or oil hardening industry is nickel on kieselguhr. The hydrogenation is a 3 phase, slurry process and the catalyst has to be filtered from the reaction mass.
Bill C

 

[moltenmetal]

Great information, Bill. Thanks for that.

 

[25362]

The name is Raney. It is prepared from alloy as bchoate says by dissolving the Al in a warm solution of sodium hydroxide.