Natural products, processing

N.N. Supercritical Fluids - Material and Natural Products Processing, Nice/France, 1998, Institut National Polytechnique de Lorraine... 

J. Hawari, A. Halasz, L. Dusseault, J. Kumita, E. Zhou, L. Paquet, G. Ampleman, S. Thiboutot, Proc. 5th Meeting on Supercrit. Fluids Materials and Natural Products Processing, Nice, (ed. M. Perrut, P. Subra), (1998) 161. 

Verillon F, Boutant R, Proceedings of the Fifth Meeting on Supercritical Fluids, Materials, and Natural Products Processing, March 23-25, 1998, Nice, France (1998). 

Weber A, Tschernjaew J, Kummel R. Coprecipitation with compressed antisolvents for the manufacture of microcomposites. Proceedings of the 5th meeting on Supercritical Fluids Materials and Natural Products Processing, Nice,... 

Kordikowski A, Shekunov T, York P. Crystallization of sulfathiazole pol5morphs using CO2. Proceedings of the 7th meeting on supercritical fluids. Particle design— Materials and natural products processing, Antibes/Juan-les-Pins, France, 2000. 

Kerst, A.W. and SchlQnder, E-U, (1998) Fluid dynamics and liquid side mass transfer at high pressures in Proc. 5 Meeting on Supercritical Fluids Materials and Natural Product Processing, Pemit, M and Supra, P., (eds.) 457-462. 

The chemoselectivity and diastereoselectivity of the method are remarkably high, so many natural product processes use this transformation. The reaction condition was optimized and applied to the total synthesis of (+)-Lepiddin A by Evans and Black as shown in Scheme 8.49. As a result, a mrsture of dioxane and THF (6 1 ratio) gave the best diastereoselectivity with the reasonable yield [57j. 

A natural concentration will be in the 3rd Thematic Programme on "Promoting Competitive and Sustainable Growth" and specially its Key Action 1 on Products, Processes and Organisation . 

Olefins are produced primarily by thermal cracking of a hydrocarbon feedstock which takes place at low residence time in the presence of steam in the tubes of a furnace. In the United States, natural gas Hquids derived from natural gas processing, primarily ethane [74-84-0] and propane [74-98-6] have been the dominant feedstock for olefins plants, accounting for about 50 to 70% of ethylene production. Most of the remainder has been based on cracking naphtha or gas oil hydrocarbon streams which are derived from cmde oil. Naphtha is a hydrocarbon fraction boiling between 40 and 170°C, whereas the gas oil fraction bods between about 310 and 490°C. These feedstocks, which have been used primarily by producers with refinery affiliations, account for most of the remainder of olefins production. In addition a substantial amount of propylene and a small amount of ethylene ate recovered from waste gases produced in petroleum refineries. 

Nature Identical Flavor Matenal A flavor ingredient obtained by synthesis, or isolated from natural products through chemical processes, chemically identical to the substance present in a natural product and intended for human consumption either processed or not eg, citral obtained by chemical synthesis or from oil of lemongrass through a bisulfite addition compound. 

This process may also be referred to as destmctive distillation. It has been appHed to a whole range of organic materials, more particularly to natural products such as wood (qv), sugar (qv), and vegetable matter to produce charcoal (see Fuels frombiomass). However, in the present context, coal usually yields coke, which is physically dissimilar from charcoal and appears with the more familiar honeycomb-type stmcture (27). 

In 1991, there were approximately 418 sulfur production plants associated with oil and gas production in operation throughout the world. Approximately 86% of these plants were based on the Claus process, and there were 118 Claus units operating in natural gas processing faciHties (11). 

Examination of the various classified listings of herbicides provides iasight iato the processes and approaches that lead to the discovery of new pesticides. The four principal development approaches are random screening, imitative chemistry, testing natural products, and biorational development. 

Manufacture and Processing. The industry related to iodine production began a few years after the discovery of the element by Courtois in 1811. The production processes are based on the raw materials containing iodine seaweeds, mineral deposits, and oh-weh or natural gas brines. 

Other natural gas Hquids include natural gasoline [8006-61 -9] which is composed of the pentanes and heavier components of the natural gas stream, and ethane [74-84-0]. Most recendy ethane has become the principal product of natural gas processing plants. 

Historically, about two-thirds of the LPG produced in the United States came from natural gas processing and one-third was produced from refinery operations (2). In 1991, this ratio was 61% from natural gas processing and 39% from refinery operations. Total production of LPG in 1991 was 76.85 X 10 m (294.19 x 10 bbl) from natural gas processing and 30.08 x 10 m (189.23 x 10 bbl) produced from refinery operations. 

Interest in synthetic naphthenic acid has grown as the supply of natural product has fluctuated. Oxidation of naphthene-based hydrocarbons has been studied extensively (35—37), but no commercially viable processes are known. Extensive purification schemes must be employed to maximize naphthene content in the feedstock and remove hydroxy acids and nonacidic by-products from the oxidation product. Free-radical addition of carboxylic acids to olefins (38,39) and addition of unsaturated fatty acids to cycloparaffins (40) have also been studied but have not been commercialized. 

The by-product of this process, pelargonic acid [112-05-0] is also an item of commerce. The usual source of sebacic acid [111-20-6] for nylon-6,10 [9008-66-6] is also from a natural product, ticinoleic acid [141-22-0] (12-hydroxyoleic acid), isolated from castor oil [8001-79-4]. The acid reacts with excess sodium or potassium hydroxide at high temperatures (250—275°C) to produce sebacic acid and 2-octanol [123-96-6] (166) by cleavage at the 9,10-unsaturated position. The manufacture of dodecanedioic acid [693-23-2] for nylon-6,12 begins with the catalytic trimerization of butadiene to make cyclododecatriene [4904-61-4] followed by reduction to cyclododecane [294-62-2] (see Butadiene). The cyclododecane is oxidatively cleaved to dodecanedioic acid in a process similar to that used in adipic acid production. 

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