Effect of sulfuric acid concentration on the rates of hydrolysis of ethyl benzoate ethyl thiolbenzoate, and ethyl thionbenzoate

1977 ◽  
Vol 99 (22) ◽  
pp. 7224-7228 ◽  
Author(s):  
John T. Edward ◽  
Sin Cheong Wong
Keyword(s):  
Sulfuric Acid ◽  
Acid Concentration ◽  
Sulfuric Acid Concentration ◽  
Ethyl Benzoate ◽  
Hydrolysis Of

The hydrolysis of thioacetic, thiobenzoic, and three substituted thiobenzoic acids in perchloric and sulfuric acids

1978 ◽  
Vol 56 (7) ◽  
pp. 935-940 ◽  
Author(s):  
John T. Edward ◽  
Graeme Welch ◽  
Sin Cheong Wong
Keyword(s):  
Sulfuric Acid ◽  
Activity Coefficients ◽  
Acid Concentration ◽  
Perchloric Acid ◽  
Transition States ◽  
Sulfuric Acid Concentration ◽  
Thiobenzoic Acid ◽  
The Difference ◽  
Different Response ◽  
Hydrolysis Of

The rates of hydrolysis of thioacetic, thiobenzoic, and three substituted thiobenzoic acids increase with concentration of solvent sulfuric or perchloric acid to a maximum in 30–40% acid and then decrease. Yates–McClelland r, Bunnett–Olsen [Formula: see text], and Hammett ρ parameters, and entropies of activation indicate an AAC2 mechanism over this range of acid concentrations. In acid concentrations above 50–60% the rates increase sharply and the same mechanistic criteria now indicate an AAc1 mechanism. The difference between the rate–acidity profile of thiobenzoic acid and that of ethyl thiolbenzoate can be explained by the different response of the activity coefficients of their transition states to increase in sulfuric acid concentration.

Study on Sugar Production Conditions of Dilute Sulfuric Acid Hydrolysis of Corn Straw

2014 ◽  
Vol 1008-1009 ◽  
pp. 97-100
Author(s):  
Qing Sun ◽  
Shu He Huang ◽  
Bo Wang ◽  
Xiao Run Deng ◽  
Jia Sheng Yi ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Reaction Time ◽  
Acid Hydrolysis ◽  
Acid Concentration ◽  
Sulfuric Acid Concentration ◽  
Sugar Yield ◽  
Corn Straw ◽  
Experimental Conditions ◽  
Dilute Sulfuric Acid ◽  
Hydrolysis Of

In this paper, through the study of reducing sugar conditions of corn straw hydrolysis under acidic condition, looking for the production of experimental conditions relatively reasonable. Mainly by dilute sulfuric acid hydrolysis of corn straw by single factor test, effects of sulfuric acid concentration, temperature, reaction time, particle size, ratio of solid to liquid five factors, effects on sugar yield of corn straw. The dilute sulfuric acid concentration 5%, ratio of solid to liquid was 1:14, when the reaction time is 140 min, particle fineness of 120 mesh, the reaction temperature is 100 °C, corn stalk sugar yield reached a maximum 20.11%.

scholarly journals HIDROLISIS SELULOSA DARI SEKAM PADI (Oryza sativa) MENJADI GLUKOSA DENGAN KATALIS ARANG TERSULFONASI

KOVALEN ◽  
2016 ◽  
Vol 2 (3) ◽  
Author(s):  
Adeks Pramana ◽  
Abdul Rahman Razak ◽  
Prismawiryanti Prismawiryanti
Keyword(s):  
Oryza Sativa ◽  
Sulfuric Acid ◽  
Acid Concentration ◽  
Rice Husk ◽  
Contact Time ◽  
Sulfuric Acid Concentration ◽  
Cellulose Hydrolysis ◽  
Hydrolysis Reaction ◽  
Rice Husks ◽  
Hydrolysis Of

Cellulose hydrolysis from rice husk (Oryza sativa) into glucose with sulfonated charcoal catalyst was conducted. The aim of this research was to determine sulfuric acid concentration and contact time on the sulfonation process of charcoal which would produce the highest glucose rendement from cellulose hydrolysis of rice husk. Sulfuric acid concentrations in this experiment were 8, 10, and 12 N with variation of contact time of 4, 6, 8, 10 and 12 hours respectively.  Rice husk was delignified with NaOH 10% to produce cellulose which was hydrolyzed by sulfonated charcoal catalyst. Hydrolysis reaction with the ratio cellulose/aquadest 1:25 (w/v) was conducted in autoclave with temperature 130 oC for 3 hours. The result showed that 8 N concentration of sulfuric acid and 12 hours of contact time produced the highest glucose rendement 17,9%. Keywords : rice husks, cellulose, glucose, sulfonated charcoal

scholarly journals Optimization of hydrolysis conditions for xylans and straw hydrolysates by HPLC analysis

2021 ◽  
Author(s):  
Alexander Beckendorff ◽  
Anne Lamp ◽  
Martin Kaltschmitt
Keyword(s):  
Sulfuric Acid ◽  
Acid Concentration ◽  
Hplc Analysis ◽  
Degradation Products ◽  
Sulfuric Acid Concentration ◽  
Corn Cob ◽  
Hydrolysis Time ◽  
Conversion Rates ◽  
Hydrolysis Temperature ◽  
Hydrolysis Of

AbstractOligosaccharide analysis is commonly done by acid hydrolysis and following HPLC analysis. A major problem is the incomplete hydrolysis of oligosaccharides and disaccharides and the increasing formation of volatile furfural from pentose monomers and hydroxymethylfurfural (HMF) from hexose monomers. This paper optimizes the conditions of hydrolysis approaches and proposes a method for oligosaccharide quantification. The optimal condition for hydrolysis of model xylan from corn cob was found to be for 100 °C hydrolysis temperature, 120 min hydrolysis time, and 2 wt% sulfuric acid concentration. Under these conditions, the total free and bound xylose yield was 77.4% and hemicellulose conversion 87.4% respectively; no degradation products were found. The optimal conditions for hydrolysis of model xylan from beech wood were found to be for 120 °C hydrolysis temperature, 120 min hydrolysis time, and 2 wt% sulfuric acid concentration. Under these conditions, the total free and bound xylose yield was 65.1% and hemicellulose conversion 70.5% respectively; no degradation products were found. For pentosan hydrolysate, conditions were further optimized (110 °C, 60 min, 2 wt% H2SO4). Standard addition of xylan from the corn cob for hydrolysation showed similar conversion rates (< 2% deviation); no matrix effects were detected.

scholarly journals Release of reducing sugars from water hyacinth by thermochemical and enzymatic hydrolysis

2021 ◽  
Vol 6 (1) ◽  
pp. 156-164
Author(s):  
Jessica E. Guzmán-Pérez ◽  
◽  
Oscar J. Salinas-Luna ◽  
Ernesto Favela-Torres ◽  
Nohemi López-Ramírez ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Enzymatic Hydrolysis ◽  
Acid Concentration ◽  
Water Hyacinth ◽  
Dry Matter ◽  
Eichhornia Crassipes ◽  
Reducing Sugars ◽  
Sulfuric Acid Concentration ◽  
Raw Material ◽  
Thermochemical Pretreatment

Water hyacinth (Eichhornia crassipes) is considered a pernicious herb in many parts of the world due to its rapid growth. However, for its high content of cellulose and hemicellulose, it could be considered as raw material to produce fermentable sugars. In this work, the effect of sulfuric acid concentration by thermochemical pretreatment and enzymatic hydrolysis on the release of sugars from water hyacinth was evaluated. Initially, the effect of the sulfuric acid concentration from 1.5 to 9% at 120 ºC was evaluated. With 1.5%, the release of reducing sugars was 160 milligrams of reducing sugars per gram of dry matter (mg red-sug/g dm). After the thermochemical pretreatment, the enzymatic hydrolysis with the cellulase complex (NS22086) allowed obtaining a reducing sugars concentration up to 317 mg red-sug/g dm. These thermochemical and enzymatic approaches to recover reducing sugars from water hyacinth is promising and should be evaluated for bioprocess using reducing sugars as the main source of carbon, such as bioethanol production.

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