Cellulose valerate

Cellulose valerates have been synthesized by conventional methods using valeric anhydride and sulfuric acid catalyst (25,26). Alternatively, the cellulose is activated by soaking in water, which is then displaced by methylene chloride or valeric acid the temperature is maintained at <38° C to minimize degradation. 

Cellulose triesters, moisture properties of selected, 5 416t Cellulose trinitrate, 5 396 Cellulose valerate(s), 5 419 moisture properties, 5 416t Cellulose x, 5 373, 378-379 8 21 Cellulose xanthate, 4 716 5 383 20 559 Cellulosic-acrylic fibers, dyeing, 9 201-202 Cellulosic fiber blends, dyeing, 9 199-202 Cellulosic fiber—nylon blends, dyeing, 9 202 Cellulosic fibers, 18 96... 

Cellulose alkyl ester Single Tg, transparency II was cellulose butyrate, cellulose propionate, or cellulose valerate Kusumi et al. (2008)... 

Cellulose octauoate Cellulose palmitate Cellulose propionate Cellulose valerate Chloral, polyacetal... 

Other mixed esters, eg, cellulose acetate valerate [55962-79-3] cellulose propionate valerate [67351-41-17, and cellulose butyrate valerate [53568-56-2] have been prepared by the conventional anhydride sulfuric acid methods (25). Cellulose acetate isobutyrate [67351-38-6] (44) and cellulose propionate isobutyrate [67351-40-0] (45) have been prepared with a 2inc chloride catalyst. Large amounts of catalyst and anhydride are required to provide a soluble product, and special methods of delayed anhydride addition are necessary to produce mixed esters containing the acetate moiety. Mixtures of sulfuric acid and perchloric acid are claimed to be effective catalysts for the preparation of cellulose acetate propionate in dichi oromethane solution at relatively low temperatures (46) however, such acid mixtures are considered too corrosive for large-scale productions. 

Cellulose acetate valerate, 5 421 Cellulose aminoacetates, 5 419 Cellulose-based carbon fibers, 26 735-736 Cellulose-binding module (CBM), 10 282 Cellulose butyrate... 

Cellulose phosphate(s), 5 401 8 29 20 459 flame resistant, 8 27 paper, 5 408 solubility of, 5 402 Cellulose propionate manufacture of, 5 418 moisture properties, 5 416t Cellulose propionate valerate, 5 421 Cellulose propionate isobutyrate, 5 421 Cellulose substrates, dyeability of, 9 482-483... 

The de novo synthesis of fatty acids in the mammary gland utilizes mainly acetate and some (3-hydroxybutyrate. These precursors arise from the microbial fermentation of cellulose and related materials in the rumen. Once in the mammary gland, acetate is activated to acetyl-CoA. The mechanism of fatty acid synthesis essentially involves the carboxylation of acetyl-CoA to malonyl-CoA, which is then used in a step-wise chain elongation process. This leads to a series of short-chain and medium-chain length fatty acids, which differ by two CH2 groups (e.g., 4 0, 6 0, 8 0, etc.) (Hawke and Taylor, 1995). These are straight-chain, even-numbered carbon fatty acids. However, if a precursor such as propionate, valerate or isobutyrate, rather than acetate, is used, branched-chain or odd-numbered carbon fatty acids are synthesised (Jenkins, 1993 see Chapter 2). 

A number of various esters of cellulose are known, for example, propionate and butyrate and mixed esters such as acetate-butyrate, propionate-isobutyrate, and propionate-valerate. The mixed esters have found use in plastic composites when good grease- and water-repelling properties are required. 

Lange J-P, Price R, Ayoub PM, Louis J, Petrus L, Clarke L, Gosselmk H (2010) Valeric biofuels a platform of cellulosic transportation fuels. Angew Chem Int Ed49(26) 4479-4483... 

CO-3-hydroxy valerate) (PHBV) and cellulose by extrusion blending, using a co-rotating twin screw extruder with a temperature profile ranging from 160 to 145 °C. PHBV pellets were dried, dry mixed with a cellulose nanowhisker powder and extruded. The extrudate was cooled in a water bath and the final pellets were dried. This material did not have the same mechanical properties and the same cellulose dispersion as the analogous composite prepared with solvent casting process. It was necessary to add a compatibilizer to improve the dispersion. 

The effect of heating on structural transitions and crystallization of cellulose acetates, butyrates, and valerates has been investigated. The glass transition... 

Natural fibers, such as cotton, kenaf, coir, jute, flax, sisal, hemp, and wood, etc., become the first choice due to their biodegradabihty. Some synthetic biodegradable fibers have also been used for nonwoven apphcations, including cellulose esters such as cellulose acetate, rayon, lyoceU, etc., polyesters such as poly(lactic acid) (PLA), poly(caprolactone) (PCL), poly(hydroxybutyrate) (PHB), poly(hydroxybutyrate-co-valerate) (PHBV), Biomax, Biopol, polytetramethylene adipate-co-terephthalate (PTAT), etc., and water solubles such as poly(vinyl alcohol) (PVA), etc. 

Polyhydroxybntyrate/valerate (PHBV), one of the truly biodegradable non-cellulose based plastics, is a bacterially grown polyester with properties similar to PP. It was sold nnder the name Biopol. PHPB is one member of family of poly hydroxyalkanoates (PHAs) prodnced by microbes from sugars or other biobased materials. Metabohx PHAs are reported to be better water vapor barriers than most biodegradable plastics. 

Seecof and Wagner 171) obtained a transaminase from Neurospora which catalyzed the reaction between phenylalanine and a-keto-/3-methyl-valerate and o-ketoisovalerate. This enzyme was purified fifteen- to thirtyfold by (NH4)j304, AlCU, and DEAE-cellulose fractionation. The enzyme preparation was found to be active with phenylalanine, isoleucine, leucine, valine, and methionine, decreasu in the order listed. 

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