Polyols production

Texaco sold its polyol product line and a tolling agreement to Arco in 1987. Formerly Miles (formerly Mobay). 

The 1995 Canadian and United States sugar alcohol (polyol) production is shown in Table 2. The market share of each is also given. Liquids comprise 48% crystalline product comprises 39% and mannitol comprises 13% of the polyol market. An estimate of total U.S. sorbitol capacity for 1995 on a 70% solution basis was 498,000 t. ADM, Decatur, lU., produced 68,200 t Ethichem, Easton, Pa., 13,600 t Lon2a, Mapleton, lU., 45,400 t Roquette America, Gurnee, lU., 68,200 t and SPI Polyols, New Castle, Del., 75,000 t (204). Hoffman-LaRoche, which produces sorbitol for captive usage in the manufacture of Vitamin C (see Vitamins), produced about 27,300 t in 1995. 

Table 2. 1995 United States and Canada Polyols Product Market Share...

Filter/dry OH-functionality of polyol depends on structure of R Difficult to "cap all 2° OH groups with EO Side reactions (esp. proton abstraction) limit functionality of Urethane-grade polyol product and create unwanted functional groups... 

The glycolysis of rigid polyurethane foams produces polyol products which can be reintroduced into the production cycle of PUR insulation materials to form materials with properties practically equivalent to dtose of materials produced using virgin polyols. Aromatic amines produced as by-products in die glycolysis process are toxic and therefore undesired side products. The most frequently observed side product is diphenylmedianediamine (DMDA), which is formed... 

Rhodium losses can also be reduced by using a two-phase system to separate the polyol products from the catalyst solution (64). In this modification the reaction is carried out in a production solvent (e.g., tetraglyme). In order to separate the products, water and an essentially water-immiscible organic extraction solvent (e.g., dichloromethane or chloroform) are added. The resulting two-phase system then consists of a water phase containing the alcohol products and an organic phase containing essentially all the rhodium complex. 

D. C. Elliott, Final Report CRADA with Int. Polyol Chemicals Inc. and Pacific Northwest National Laboratory Process Optimization for Polyols Production from Glucose, PNNL-11476, Pacific Northwest National Laboratory, Richland, Washington, 1997. 

The resulting polyol resembles the product that is hypothesized for the oligomerization of triglycerides via air oxidation, with the exception that there is a large increase in the hydroxyl content of the polyol product, and there is very little, if any, of the starting epoxide left unreacted. In addition, the epoxidation process does not produce low molecular weight chain scission products, which are a by-product of the blown oil process. The hydroxylation of epoxidized triglycerides is illustrated in Fig. 17. 

The desire to minimize this competitive oligomerization has motivated research into alternative means to decrease the polydispersity and simultaneously increase the molecular weight of the seed-oil derived polyols. Recent patents [128, 129] investigate an approach previously demonstrated for the hydroformylated polyols [130-132], i.e., hydroxylation of the fatty acid alkyl ester followed by polymerization from a petrochemically derived initiator molecule. Inventors state that this approach provides an improvement over previous epoxidized/hydroxylated polyols by allowing better control of the molecular weight and the functionality of the polyol products. 

Polyols, namely arabitol and xylitol, have potential chemical, pharmaceutical, and food applications. The latter polyol is currently produced by chemical means, in spite of xylitol bioproduction receiving increased interest (40). Previously it was shown (22) that D. hansenii CCMI 941, under oxygen limitation conditions, coproduces both of arabitol and xylitol in chemically defined medium. In the present work, we evaluated the polyol production by D. hansenii grown on the BSG acid posthydrolysate. 

National Emission Standards for Hazardous Air Pollutant Emissions for Polyether Polyols Production... 

By contrast, biosynthetic studies on whole fruits have been limited and, probably because of the low levels of monoterpenes In grapes, the pathways In Vltls species remain unexplored. Since monoterpenes important to the flavor of grapes are mainly acyclic, Interconversions of neryl, geranyl and llnalyl derivatives may be of special significance. The oxidative steps leading to polyol production represent a shunt of flavor-active compounds to flavorless forms and require investigation. 

Reduction of CO to compounds containing C—H and/or C—C bonds has been actively studied because these reductions are important in the conversion of coal-derived CO into fuels and organic chemicals. Reactions in this class include methanation, MeOH synthesis, and Fischer-Tropsch (F-T) synthesis, e.g., equations (b)-(d) equation (d) yields a range of hydrocarbon and oxygenate (ROH and polyol) products. 

Table 14.S offers an indication of the economics of polyether-polyol production, when the adduct used is glycerin.

Polyalkylene oxide polyether polyols are the most important group of polyols for PU, representing around 80% of the total oligo-polyols production. The general formula of a polyalkylene oxide poly ether polyol is presented in Figure 4.3. 

Unfortunately, DMC catalysts are not efficient for EO polymerisation, and it is practically impossible to obtain PO-EO block copolymers with this catalyst. Acidic catalysts are not used on an industrial scale for alkylene oxide polymerisation due to the formation of substantial amounts of cyclic ethers as side products. Acidic catalysts are used industrially only for the synthesis of polytetrahydrofuran polyols or, to a lesser extent, for tetrahydrofuran - alkylene oxide copolyether polyol fabrication (see Sections 7.1, 7.2 and 7.3) Other catalysts have a minor importance for large scale polyether polyol production. 

A schematic showing polyester polyols production is presented in Figure 8.3. 

The major application for epoxidized oils made by these means is their use as polyvinyl chloride (PVC)-plasticizers and stabilizers because of their ability to catch free HCl and slow degradation. Additionally, they can be used as reactive diluents for paints and as intermediates for polyurethane-polyol production. The most important product today is epoxidized soybean oil. The total worldwide production amounts to -200,000 t/y (4). 

Starch-Modifying Enzymes Starch is one of the most abundant carbohydrates in terrestrial plants and the most important polysaccharide used by humankind. This polymer is normally processed and used in a variety of products such as starch hydrolysates, starch or maltodextrin derivatives, fructose, glucose syrups, and cyclodextrins [148, 149]. In addition, starch is widely used as a raw material in the paper industry, in polyol production, and as economic substrate for many microbial fermentations [149]. Starch consists of a large number of glucose units that can be linearly attached as hehcal amylose [ 99% a-(l-4) and 1% a-(l-6) bonds] or branched as amylopectin [ 95% a-(l-4) and 5% a-(l-6) bonds] [69]. In nature, four types of starch-converting enzymes exist (i) endoamylases (ii) exoamylases (iii) debranching enzymes and (iv) transferases. 

More detailed information on polyol production by LAB or on the metabolic engineering strategies applied for the synthesis of these compounds by LAB can be found in the reviews of Saha and Racine, Moon et al, and Ortiz et al. 

Monedero, V., Perez-Martinez, G, and Yebra, M.J. (2010) Perspectives of engineering lactic acid bacteria for biotechnological polyol production. Appl Microbiol Biotechnol, 86, 1003-1015. 

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