Adipic acid is an important intermediate for the chemical industry, which produces several million tons of it every year. By far the biggest portion of the output is used to produce polyamide 6.6 (nylon), which is turned into fibers for lightweight fabrics that are tear and abrasion-resistant as well as into strings for plucked instruments, tennis racket strings, and wear-resistant parts such as cogwheels. In addition, adipic acid is used as a raw material for certain polyurethanes, which are found in ski boots, sports shoe soles, golf balls, foams, coatings, and adhesives, for example. Adipic acid is also used to produce plasticizers for cables, hoses, foils, and food packaging made of PVC. Other applications include the use in additives that make paints and coatings resistant to low temperatures and as components of lubricants. Adipic acid itself is also approved for use as an acidulant in food (E355). The name is based on the Latin word adipes (animal fats). Adipic acid used to be produced by oxidyzing fat. This natural starting material was later replaced by petroleum-based raw materials. Until now, its synthesis required several steps. In the recently achieved reaction, researchers succeeded in producing adipic acid directly from butadiene for the first time. The scientists accomplished this using a catalyst they had developed specifically for this purpose. In the new process, carbon monoxide and water are used to attach two carboxyl groups to a butadiene molecule in a single process step.