Degraded Terpenes

Although the amount of extract was linear in the 5 hour period, it probably will not be over a longer period of time. In a batch system, since the composition of the feed oil will change with time, the amount of oxygenated compounds in the extract also will change. Based on these assumptions, it was found that at least 50 hours of extraction would be necessary to obtain a 5-fold oil at a flow rate of 500 mL/min. However, leaving the oil at 70 C for 50 hours would probably result in the formation of undesirable terpene degradation products. Therefore, no attempt was made to produce a 5-fold oil with the system described. 

Yang, Y., Kayan, B., Bozer, N., Pate, B., Baker, C., and Gizir, A.M. 2007. Terpene degradation and extraction from basil and oregano leaves using subcritical water. Journal of Chromatography A, 1152, (1-2), 262-267. 

Essentia.1 Oils. Essential oils (qv) are extracted from the flower, leaf, bark, fmit peel, or root of a plant to produce flavors such as mint, lemon, orange, clove, cinnamon, and ginger. These volatile oils are removed from plants either via steam distillation, or using the cold press method, which avoids heat degradation. Additional processing is sometimes employed to remove the unwanted elements from the oils, such as the terpenes in citms oils which are vulnerable to oxidation (49,50). 

In Acanthomyops, the strikingly different incorporations following the two mevalonate feedings indicate that mevalonate is not degraded before being built into terpenes but rather is decarboxylated, as in the classical mevalonic acid pathway. 

Degradation of many terpenes has been examined including p-pinene, o-limonene, and trani-caryophyllene (Grosjean et al. 1993c). 

The initial hydroxylation in the degradation of some terpenes the ring methylene group of camphor by Pseudomonas putida (Katagiri et al. 1968 Tyson et al. 1972 Koga et al. 1986), and the isopropylidene methyl group of linalool by a strain of P. putida (Ullah et al. 1990). 

Fourier transform infrared (FTIR) spectroscopy, 13C nuclear magnetic resonance (NMR) spectroscopy, ultraviolet-visible (UV-VIS) and fluorescence spectroscopy can be integrated with chromatographic techniques especially in the study of ageing and degradation of terpenic materials. They can be used to study the transformation, depletion or formation of specific functional groups in the course of ageing. 

Terpene resins are most commonly used in adhesive production, where they confer very strong tackifying properties. The terpene resins improve the resistance of adhesives to oxidative degradation. These resins are normally produced from p-pinene and are light yellow in colour. Polymers of dipentene and limonene are also available as resins. 

This chapter surveys different process options to convert terpenes, plant oils, carbohydrates and lignocellulosic materials into valuable chemicals and polymers. Three different strategies of conversion processes integrated in a biorefinery scheme are proposed from biomass to bioproducts via degraded molecules , from platform molecules to bioproducts , and from biomass to bioproducts via new synthesis routes . Selected examples representative of the three options are given. Attention is focused on conversions based on one-pot reactions involving one or several catalytic steps that could be used to replace conventional synthetic routes developed for hydrocarbons. 

Hydroxy-4,4,6-trimethyl-2,5-hexadien-l-one, lanierone, 254, is a component of the complex aggregation signal of male Ipspini [468]. The carbon skeleton of 254 is the same as in isophorone 255, which has been identified as a volatile constituents of females of Ips typographus. Whether these compounds are degradation products of higher terpenes awaits further investigations. 

Simple lipids Lipids whose hydrolysis produces a relative small set of degradation products. Most are terpenes. 

The first suitable representative of this class of substances, 6-methyl-5-heptene-2-one, was investigated by Neuberg and Lewite. This ketone, which is a natural constituent of ethereal oils, can also be obtained by degradation of various aliphatic and cyclic terpenes. By means of fermenting yeast it is converted to 6-methyl-5-heptene-2-ol,... 

In addition to linalyl acetate, the oil contains linalool and other terpene alcohols, as well as their acetates. When the volatile components are evaporated, a distinct ambergris note develops that is attributed to oxidative degradation products of sclareol [515-03-7] [746-750a]. Sclareol is the main component in the concrete, obtained by solvent extraction of S. sclarea L. leaves [750b]. 

Volatile compounds formed by anabolic or catabolic pathways include fatty acid derivatives, terpenes and phenolics. In contrast, volatile compounds formed during tissue damage are typically formed through enzymatic degradation and/ or autoxidation reactions of primary and/or secondary metabolites and includes lipids, amino acids, glucosinolates, terpenoids and phenolics. 

Abscisic acid, one of five known types of plant hormone of general distribution throughout higher plants, is not regarded as a tme terpene because it arises by degradation of a carotenoid.99 99b However, its stmcture (Fig. 22-4) is that of a sesquiterpene. 

The negative values for the degradation of a-pinene and of A -carene at 6h-on-stream correspond to an increase of these terpenes in the products. After 30 h-on-stream all the main terpenes are degraded during the HDS treatment. It should be noted that the conversion of /3-pinene is higher in the turpentine oil than in the /3-pinene fraction. This is not due to a change in the terpene concentration in an experiment of HDS carried out with a mixture of a-pinene, /3-pinene and A -carene (in the same proportion as in the turpentine oil), the conversion of /3-pinene was 12%, very close to the conversion recorded... 

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