ETHANE CHEMICALS

The main source for ethane is natural gas liquids. Approximately 40% of the available ethane is recovered for chemical use. The only large consumer of ethane is the steam cracking process for ethylene production. A minor use of ethane is its chlorination to ethyl chloride:

By-product HCl may be used for the hydrochlorination of ethylene to produce more ethyl chloride. Hydrochlorination of ethylene, however, is the main route for the production of ethyl chloride:

Figure 1.1. The Transcat process for producing vinyl chloride from ethane.

Major uses of ethyl chloride are the manufacture of tetraethyl lead and the synthesis of insecticides. It is also used as an alkylating agent and as a solvent for fats and wax.

A small portion of vinyl chloride is produced from ethane via the Transcat process. In this process a combination of chlorination, oxychlorination, and dehydrochlorination reactions occur in a molten salt reactor.

The reaction occurs over a copper oxychloride catalyst at a wide temperature range of 310–640°C. During the reaction, the copper oxychloride is converted to copper(I) and copper(II) chlorides, which are air oxidized to regenerate the catalyst. Figure 1.1 is a flow diagram of the Transcat process for producing vinyl chloride from ethane. Vinyl chloride is an important monomer for polyvinyl chloride (PVC).

The main route for obtaining this monomer, however, is via ethylene. A new approach to utilize ethane as an inexpensive chemical intermediate is to ammoxidize it to acetonitrile. The reaction takes place in presence of a cobalt-B-zeolite.