Лако-красочные материалы — производство

Sandalwood oil is obtained by distillation of the parasitic tree Santa — lum album. The major components of the oil are the santalols (27, 28). Many syntheses of these and related chemicals have been reported but, elegant as they are, none compete economically with the oil itself. The synthetic sandalwood materials fall into two main […]

Two main families of cedarwood oils are used in perfumery. The first is extracted from trees of the family Juniperus. These oils are known as English, Texan or Chinese cedarwood and their components are derived from the cedrane and thujopsane groups of sesquiterpenes. Atlas and Himalayan cedarwoods are obtained from Cedrus species and their terpenes […]

The Carroll, or an equivalent, reaction between linalool and an acetoacetic ester gives geranylacetone. Further elaboration, as shown in Scheme 4.28, produces sesquiterpenes such as nerolidol, farnesol and bisabolol which have some perfumery use, although their odours are weak. Bisabolol is used mostly because of its anti-inflammatory and anti-bacterial properties. The main use for these […]

Camphene can be obtained from a-pinene through acid-catalysed rearrangement. The details of the mechanism are shown in Scheme 4.26. It was study of this reaction and related conversions that led to the elucidation of the Wagner-Meerwein rearrangement. Acid-catalysed addition of acetic acid to camphene gives isobornyl acetate; the first carbocation formed in this conversion is […]

The synthesis of menthol makes an interesting study since it neatly illustrates the balance of economic and technological factors governing the range of production methods that can be employed commercially. Menthol (l-methyl-4-isopropylcyclohexan-3-ol) is a monocyclic monoterpene which possesses three asymmetric carbon atoms and therefore exists in eight stereoisomeric forms (13-20). L-Menthol is the most highly […]

The three most important cyclic monoterpenes are L-menthol, l — carvone and a-terpineol (including its esters). L-Menthol occurs in а number of mint oils and is used not only for its minty odour, but also,and more importantly, for its physiological cooling effect. Its chemistry is of such interest and significance that it warrants a section […]

The alcohols geraniol-nerol, linalool, citronellol and their esters are the largest tonnage materials of this class. Their syntheses are described in detail above and no further explanation is necessary here. The chemical stability of these materials is limited by the unsaturation in them. To improve stability, particularly in oxidative media such as bleaches and laundry […]

A small number of hemiterpenes are used in perfumery, the most important of which are prenyl acetate and benzoate. Thioesters, such as those shown in Scheme 4.11, have extremely intense green odours reminiscent of galbanum, in which they occur naturally. The esters are usually prepared from prenyl chloride and the thioesters from the corresponding thiol […]

Another process patented by BASF is shown in Scheme 4.10. This process uses only isobutylene, formaldehyde and air as reagents; the only by-product is one molar equivalent of water per mole of product and it gives citral in just four steps, two of which run in parallel. Such elegance not only has intellectual appeal, but […]

Use of the Claisen rearrangement achieves the same conversion of methylbutenol into methylheptenone as does the Carroll reaction, but without the loss of carbon dioxide. The methanol produced instead can be recovered and recycled. In this process, as shown in Scheme 4.7, methylbutenol is treated with the readily available 2-methoxypropene to give the allyl vinyl […]