Synthetic rubber butene dehydrogenation

Butadiene. Although butadiene was produced in the United States in the eady 1920s, it was not until the start of Wodd War 11 that significant quantities were produced to meet the war effort. A number of processes were investigated as part of the American Synthetic Rubber Program. Catalytic dehydrogenation of / -butenes and / -butanes (Houdry process) and thermal cracking of petroleum hydrocarbons were chosen (12). 

Butane is primarily used as a fuel gas within the LPG mixture. Like ethane and propane, the main chemical use of butane is as feedstock for steam cracking units for olefin production. Dehydrogenation of n-butane to butenes and to butadiene is an important route for the production of synthetic rubber. n-Butane is also a starting material for acetic acid and maleic anhydride production (Chapter 6). 

The stream from the cryogenic unit which is rich in C /C-olefins can be fractionated and selectively hydrogenated (to remov traces of dienes) to yield the pure olefins. Common uses of propene are the production of polypropylene, acrylonitrile, cumene etc. Butene can be catalytically dehydrogenated to butadiene which is used in the production of synthetic rubbers. 

The other major use for the -butene fraction (both 1-butene and the 2-butenes) of the butylenes is as a feedstock for 1,3-butadiene manufacture, ultimately destined for the production of synthetic rubber. Careful thermal catalytic dehydrogenation in the presence of steam gives a 75-86% yield of 1,3-butadiene from a 25-30% butene conversion per pass (Eq. 19.55). 

Butadiene is a petroleum product obtained by catalytic cracking of naphtha or light oil or by dehydrogenation of butene or butane. It is used to produce butadiene-styrene elastomer (for tires), synthetic rubber, thermoplastic elastomers, food wrapping materials, and in the manufacture of adiponitrile. It is also used for the synthesis of organics by Diels-Alder condensation. 

In 1943 Houdry Process Corp. announced the Houdry adiabatic process for catalytic cracking which eliminated the molten salt heat transfer system. This process did not go commercial for catalytic cracking, but it was successfully used for butane dehydrogenation to produce butenes for synthetic rubber production during World War II. 

---