Cellulose pretreatment

Weil, J., et al. Cellulosic Pretreatments of Lignocellulosic Substrates, Enz. Microb. Technol, 16. 1002-1004 (1994b). 

The action of endoglucanase on Avicel, followed by incubation of the cellulose pretreated with cellobiohydrolase, enhances the apparent activity of the cellobiohydrolase as shown in Table VIII. An explanation for this is that the endoglucanase is able to break up (i.e., nick) the cellulose chains. Therefore, if the crystalline cellulose has been treated first with endoglucanase, reactive sites for cellobiohydrolase attack are created. 

Cellulose pretreated with acids, such as sulfuric acid or hydrochloric acid followed by a wash of the sample to neutrality also shows an increased rate of decomposition but generates more liquid pyrolytic products. These samples produce higher yields of levoglucosan associated with the decrease of hydroxyacetaldehyde. Inorganic ions S04 or Cr are found incorporated in the acid-pretreated and washed cellulose [38] (see also Section 7.3). 

Cellulose pretreated with alkali-metal hydroxides reacts with tri-ehloroacetonitrile to give cellulose 2,2,2-trichloroacetimidate (23) tri-... 

Spano reported that cellulose pretreated by roll-milling with an energy input of 0.25 kilowatt per hour per pound was enzymatically hydrolyzed to the extent of 45% in 24 hours. The results of this were said to be encouraging (13). 

San Martin R, Aguilera JM Hohlbetg Al (1988) Effect of cellulose pretreatment on red-algae agar extractability. Carbohyd Polym 8 33-43... 

Bioethylene and green PE is one of the successful biorefinery processes. To compete with PE produced from oil resources, the green PE process must be improved and developed continuously. The efficient process improvement requires much knowledge and technology so that ethanol can be manufactured at low-cost from nonfood resources improvements are especially needed in the areas of cellulose pretreatment technology, fundamental ethanol dehydration chemistry, process and equipment development, the performance enhancement of downstream products, and so on. The successful operation of green PE industrial equipment has opened up a new era for bio-based materials, and will accelerate the quick development of the biorefinery industry. The experience developed during this process will be very important for the utilization of biorenewable resources. 

Azzam A. (1987). Saccharification of bagasse cellulose pretreated with ZnC12 and HCl. 

Complexes formed between cellulose pretreated with liquid ammonia and the sterically hindered amines, 2-aminobutane, 2-amino-2-methylpropane, and l,l,4,4-tetramethyl-l,4-diaminobutane have been studied. The bulk of the amine group, rather than its length, may be a factor in the degree of distension observed in diffractometer tracings of the complexes. 

Selection of appropriate quaternary ammonium catalysts is limited by their stability in the reaction medium. The cellulose pretreatment requires heating in strong caustic solutions up to 120 most tetraalkyl ammonium salts undergo Hoffman degradation under these conditions. We have found two relatively stable quat salts, tetramethylammonium chloride and N,N-dimethylmorpholinium... 

Addition of a 1 1 mixture of acetone-acrylonitrile to cellulose pretreated with 10% sodium hydroxide followed by heating the mixture to 40 for 3.5 hr produced a very low D.S. (0.23) derivative. Incorporation of TMAC into the pretreatment step raised the D.S. attained under these conditions to 2.1. N,N-dimethylmorpholinium chloride was much less effective, a D.S. of 0.5 was produced. Since the pretreatment was conducted by dryblending, these results are consistant with the unique catalytic... 

Cellulose pretreated in the presense of TMAC failed to exhibit enhanced activity toward sodium trichloroacetate in an isopropanol slurry. Products with essentially identical D.S. s were isolated from "catalysed and control experiments. However, solutions of catalysed CMC, (D.S.=0.7), appeared more fiber free than those prepared from controls with similar D.S.. The catalysed solutions (1%) exhibited slightly higher viscosities (500 cp vs 325 cp) and were less thixotropic than standard CMC. Efforts to ascertain if this difference in rheological behavior can be attributed to a more homogeneous distribution of substituents are in progress. 

Cellulose Pretreatment. A. Dry-Blend Technique. Powdered cellulose (36.0 g 0.20 eq) was blended while 2.0 g (0.018 mol) of tetramethylammonium chloride in 2 ml of water was sprayed into the powder using a fine-needled syringe. A solution of 30 g sodium hydroxide in 30 ml H2O was heated to boiling the hot solution was added slowly to the TMAC treated cellulose and blending was continued for 0.5 hr. A total of 100 g of pretreated cellulose powder is obtained. 

Ethyl Cellulose. Pretreated cellulose (100 g) was charged into a two liter stirrer pipe bomb, combined with NaOH (80 g, 2.0 M), ethyl chloride (250 g, 4.0 M) and 300 mL toluene and the mixture was heated to 130 for two hours. After cooling to 5 , the bomb was opened, excess ethyl chloride was allowed to evaporate and the residue poured into two liters of water. The toluene was steam distilled from the suspension and the ethyl cellulose was recovered by filtration. Approximately 46 g of ethyl cellulose, D.S. = 1.56, was obtained. A sample of ethyl cellulose prepared under identical conditions except omitting the catalyst was obtained in reduced yield (21 g) due to the higher water... 

Keenan TM, Nakas JP, Tanenbaum SW (2006) Polyhydroxyalkanoate copolymers Irom forest biomass. J Ind Microbiol Biotechnol 33 616-626 Kim S-J, Dwiatmoko AA, Choi JW, Suh Y-W, Suh DJ, Oh M (2010) Cellulose pretreatment with l-n-butyl-3-methylimidazolium chloride for solid acid-catalyzed hydrolysis. Bioresour Technol 101 8273-8279... 

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