Petrochemicals Petrochemicals are commercially used chemicals derived from crude oil and natural gas. In some cases, petrochemicals are finished products, in others more steps are needed to achieve the requisite chemical and physical attributes. Chempetrol Overseas Limited, which Tamoil has a 45% interest, was established in May 1991 as a petrochemicals trading company. Chempetrol is based in Malta, with business operations in northwest Europe and the Mediterranean area, where it is now known as one of the leading firms in the marketing of petrochemicals. The company has a well-established marketing network covering almost the whole of the Mediterranean market with sales of one million metric tons. The Hamburg refinery has recently started to produce cyclohexane.