Three common pretreatment processes based on dilute sulfuric acid, dilute sodium hydroxide and heat treatment (autoclaving) followed by enzymatic hydrolysis were evaluated to provide comparative performance data. Among them, the best result was obtained when the pretreatment of rice husk was carried out with 3% of NaOH solution. The pretreatment of rice husk with NaOH substantially increased th...

hydrolysis of ethylene-vinyl acetate copolymer in alkaline conditions using two systems of naoh/methanol and koh/isopropanol has been studied and the formation of ethylene-vinyl alcohol copolymer was systematically examined using nmr spectroscopy and dsc measurements. vinyl acetate weight percentage and the degree of hydrolysis were calculated from nmr spectroscopy and it is shown that hydrolys...

this study was aimed to investigate the possibility of using magnesium hydroxide as an alternative for sodium hydroxide in deinking of newsprint and magazine mixture. the old newsprint and magazine mixture (onp/omg -70/30) was treated by magnesium hydroxide at three levels: 1, 1.5 and 2 percent (based on oven dried pulp weight), for 20 min. optical and mechanical properties and effluent cod loa...

Chitosan has been produced from shrimp waste by chemical method involving demineralization, deproteinization and deacetylation. The quality of chitosan depends on the conditions of the chemical extraction process. The results showed that 3% HCI and 4% NaOH were suitable concentration for demineralization and deproteinization, respectively at ambient temperature (28±2 o C). Chitosan with a high ...

The fossil properties can be increased via enrichment process. It is the process that removes sulfur and mineral matter without changing the organic structure. In this study, Çan lignite was demineralized with some mineral free acid of 5% such as HCOOH and some mineral acids of 5% such as HNO3, H2SO4, HCl, H3PO4 and HF after 5% NaOH washing. The best sulfur and mineral matter performed were obt...

To investigate the separations of all aldopentoses (ribose, arabinose, xylose and lyxose) and aldohexoses (glucose, galactose, allose, altrose, mannose, gulose, idose and talose) on the D₆ stationary phase prepared by the reaction of chloromethylated styrene-divinylbenzene copolymer and N,N,N',N'-tetramethyl-1,6-diaminohexane, we examined the effect of varying the concentration of the NaOH elue...

Formation and dynamics of an Al(OH)3 precipitation ring is studied by diffusing NaOH into a gel containing AlCl3. Limited feeding of the outer electrolyte (NaOH) is found to yield an intricate ring-dynamics which involves stopping and reversal of the direction of motion of the precipitation ring, and evolution into stationary multi-ring structures. A model of the ring-dynamics is developed by c...

this work described an efficient pseudo four-component synthesis of (10e)-n-benzylidene-2-phenylh-imidazo[1,2-a]pyridin-3-amine derivatives from 2-aminopyridin, malononitrile and arylaldehydes in the presence of naoh under solvent-free and conventional heating condition in good to excellent yields. a wide range of aromatic aldehydes would easily undergo condensations with 2-aminopyridin and mal...

BACKGROUND Due to the unsustainable consumption of fossil resources, great efforts have been made to convert lignocellulose into bioethanol and commodity organic compounds through biological methods. The conversion of cellulose is impeded by the compactness of plant cell wall matrix and crystalline structure of the native cellulose. Therefore, appropriate pretreatment and even post-treatment ar...

Phenolic compounds can be efficiently O-methylated with tetramethylammonium chloride in diglyme or polyethyleneglycol (PEG) at temperatures of 150-160 °C and in the presence of either K2CO3 or NaOH. When applying benzyltrimethylammonium chloride as a reagent, the benzylation and methylation of phenols occurs, with the benzylation product always predominating. With allyl-substituted phenols as s...