1.4.1. Petrochemical Primary Products
The manufacture of carbon monoxide and hydrogen via gasification processes together with the manufacture of carbide (for welding and some special organic intermediate ), benzene, and certain polynuclear aromatics are the only remaining processes of those employed in the 1950s for the preparation of basic organic chemicals from coal. However, these account for only a minor part of the primary petrochemical products; currenty ca. 95% are based on oil or natural gas. Furthermore, there is no doubt that the expansion in production of feedstocks for the manufacture of organic secondary products was only possible as a result of the changeover to oil. This rapid expansion would not have been possible with coal due to inherent mining constraints. It can thus be appreciated that only a partial substitution of oil by coal, resulting in limited broadening of the raw material base, will be possible in the future. The dependence of the chemical industry on oil will therefore be maintained.