Лако-красочные материалы — производство

The natural musks were always very expensive and their macrocyclic structures presented synthetic challenges which were not conquered, even on laboratory scale, until the pioneering work of Ruzicka in 1926. It was therefore of major importance to the fragrance industry when, in 1888, Baur discovered the nitromusks. He had actually been working on explosives and noticed that the product of r-butylation of trinitro­toluene (TNT) had a pleasant, sweet, musky odour. The compound was named Musk Baur® (38), although the alternative name, Musk Toluene®, eventually became more common. For a while it was also known as Tonkinol® because of the similarity of its odour to that of musk Tonkin. Baur then searched for analogues of this material and

discovered Musk Xylene1* and Musk Ketone® (synthetic routes shown in Scheme 4.43) and Musk Ambrette® (39). Musk Ketone® is con­sidered to have the closest odour to that of natural musk and Musk Ambrette®, as its name implies, has an odour reminiscent of ambrette seeds. Other nitromusks which were discovered later include Musk Tibetine® (40) and moskene (41). Musk Xylene® and Musk Ketone® are prepared from m-xylene through initial /-butylation (Scheme 4.43). Nitration of the f-butyldimethylbenzene thus produced gives Musk Xylene®, and acetylation followed by nitration gives Musk Ketone®. The other nitromusks are prepared by similar combinations of classic aromatic reactions.

The nitromusks became the main contributors of musk notes in perfumery and maintained that position until the middle of the twentieth century. However, nitromusks suffer from a number of disadvantages and the discovery of the polycyclic musks in the middle of the twentieth century led to their demise. The preparation of nitromusks can be hazardous (after all, they are related to explosives such as TNT) and, although the final products are not explosive, some of the intermediates and reagents are not free of hazard. Moreover, some nitromusks have been found to be phototoxic; that is, when exposed to sunlight they produce species which can cause allergic reactions on skin. The combined effect of all of these problems, coupled with the ready availability of good alternatives, has made the nitro — musk family obsolete.