Wax research was established as a scientific discipline in 1823. It became part of the new research area of soaps, oils, fats, and waxes. The real breakthrough of wax as an important raw material, in terms of quantity as well, occurred at the beginning of the Industrial Revolution. Ozocerite (fossil wax) was mined and refined to give ceresin (1875), Montan wax was obtained from Eocene lignite (1897), and paraffin waxes were obtained from crude petroleum. In 1935 the first fully synthetic waxes were produced by the Fischer ? Tropsch process. Polyethylene wax has been synthesized by the high pressure process since 1939, and became available by the low-pressure Ziegler process after 1953. On a laboratory scale polyolefin waxes can also be synthesized by using modern metallocene catalysts. Typically waxes do not consist of a single chemical compound, but are often very complex mixtures. Being oligomers or polymers in many cases, the components differ in their molar mass, molar mass distribution, or in the degree of side-chain branching. Functional groups (e.g., carboxyl, alcohol, ester, keto, and amide groups) can be detected in waxes, sometimes several different groups. The academic definition still quoted in chemistry text books that waxes are esters of long-chain carboxylic acids with long-chain alcohols is no longer useful. It applies fairly well only to some classical waxes, such as beeswax; others (e.g., petroleum waxes) do not fall in this category. |
