Лако-красочные материалы — производство

One of the earliest commercial routes into this key group of terpenes involved pyrolysis of Д-pinene, as shown in Scheme 4.2. When ^-pinene is heated to 500 °С, the cyclobutane ring breaks via a retro-2 + 2 cycloaddition. This ring opening is regioselective and produces the triene, myrcene. Addition of hydrogen chloride to myrcene gives a mixture of geranyl, neryl and linalyl chlorides, which can be hydro­lysed; however, the reaction with acetate anion is more efficient than that with hydroxide and so the acetate esters are usually the initial products in commercial syntheses. Fractional distillation is used to separate the various products, but is complicated by the presence of traces of chlorinated impurities and isomers formed from the opening of the cyclobutane ring in the ‘wrong’ direction.

•Cl

The two main disadvantages of this route are the cost of /Tpinene and the presence of trace amounts of chlorinated materials, which must be removed from the product.