scholarly journals Studies on Chitin V. The Action of Mineral Acids on Chitin

1962 ◽  
Vol 15 (3) ◽  
pp. 526 ◽  
Author(s):  
RH Hackman
Keyword(s):  
Hydrochloric Acid ◽  
Phosphoric Acid ◽  
Sulphuric Acid ◽  
Chain Length ◽  
Colloidal Chitin ◽  
Mineral Acids ◽  
Extensive Degradation

Chitin undergoes rapid and extensive degradation at 20�C when dissolved in ION hydrochloric acid, 21N sulphuric acid, or 85% phosphoric acid. Most of the degradation occurs in the first few minutes after the chitin is dissolved and the products formed are oligosaccharides (which are to some extent deacetylated) and N�acetyl-D.glucosamine. Glucosamine was not found except possibly in the smallest traces. "Colloidal" chitin, prepared by precipitation of chitin from solution in cold 21N sulphuric acid, has a very much shorter chain length than the chitin from which it was prepared. Chitin is more stable in dilute (2N) hydrochloric acid.

Cleavage of 3,3,4-trifluoro-2,2-dimethyloxetane by mineral acids

1985 ◽  
Vol 50 (9) ◽  
pp. 1948-1958 ◽  
Author(s):  
Václav Dědek ◽  
Ivan Veselý
Keyword(s):  
Aqueous Solution ◽  
Phosphoric Acid ◽  
Sulphuric Acid ◽  
Hydrobromic Acid ◽  
Polyphosphoric Acid ◽  
Acetyl Chloride ◽  
Main Product ◽  
Hydrogen Bromide ◽  
Mineral Acids ◽  
Sole Product

Cleavage of 3,3,4-trifluoro-2,2-dimethyloxetane (I) in an aqueous solution of sulphuric acid, phosphoric acid, hydrogen chloride, or hydrogen bromide gave a mixture of 2,2-difluoro-3-methyl-3-butenal (II) and 5,5-difluoro-2-(1,1-difluoro-2-hydroxy-2-methylpropyl)-4-hydroxy-6,6-dimethyl-1,3-dioxane (VIa); in the cleavage effected by hydrochloric or hydrobromic acid the mixture also contained 3-chloro- or 3-bromo-2,2-difluoro-3-methyl-1,1-butanediol (Vb or Vc). In alcoholic solutions of the mineral acids the cleavage afforded the corresponding acetals of butenal II and 2,2-difluoro-3-hydroxy-3-methylbutanal (IIIa). The action of sulphuric acid in the presence of acetyl chloride or acetanhydride led to 1-chloro-2,2-difluoro-3-methyl-3-butenyl acetate (IVd) or 2,2-difluoro-3-methyl-3-butenylidene diacetate (IVe), as the main product. Butenal II was a sole product of the cleavage of oxetane I by polyphosphoric acid at 150-160 °C in the gaseous phase. At temperatures above 180 °C there were also formed (in addition to butenal II) 1,1,5,5-tetrafluoro-2,6-dimethyl-1,6-heptadiene-4-ol (IX) and its formate (X).

The Pschorr cyclization. A novel Pschorr reaction with a pyrrole derivative: synthesis of a pyrrolo[1,2-c]quinazoline and a new route to arylpyrroles

1970 ◽  
Vol 23 (4) ◽  
pp. 781 ◽  
Author(s):  
S Beveridge ◽  
JL Huppatz
Keyword(s):  
Thermal Decomposition ◽  
Hydrochloric Acid ◽  
Phosphoric Acid ◽  
Spectral Data ◽  
Sulphuric Acid ◽  
Major Product ◽  
Quantitative Yield ◽  
Spiro Compound ◽  
High Yield ◽  
Pyrrole Derivative

The copper-catalysed decomposition of the diazonium chloride derived from N-(3,5 -diethoxycarbonyl -4-methylpyrrol-2-ylmethyl)-N-methanesulphonyl-o-phenylenediamine (2) gave spiro[l-methanesulphonyl - 3H-indoline - 3,2'- (3', 5'- di-ethoxycarbonyl-4-methyl-2'H-pyrrole)] (4), in high yield. However, thermal decomposition of the diazonium chloride gave 2,4-diethoxy-carbonyl-5-(N-methanesulphonyl-o-aminophenyl)-3-methylpyrrole (3) as the major product. The spiro compound (4) afforded the phenylpyrrole (3) in almost quantitative yield on treatment with concentrated hydrochloric acid, while 100% phosphoric acid or 60% sulphuric acid converted the spiro compound (4) into 1,3-diethoxycarbonyl-5-methanesulphonyl-2-methyl-4,5-dihydropyrrolo[1,2-c]quinazoline (12). The latter reaction could also be achieved thermally. Analytical and spectral data are presented which support the structures proposed.

scholarly journals Electrical response of the Summit-Greenland ice core to ammonium, sulphuric acid, and hydrochloric acid

1994 ◽  
Vol 21 (7) ◽  
pp. 565-568 ◽  
Author(s):  
John C. Moore ◽  
Eric W. Wolff ◽  
Henrik B. Clausen ◽  
Claus U. Hammer ◽  
Michel R. Legrand ◽  
...  
Keyword(s):  
Hydrochloric Acid ◽  
Sulphuric Acid ◽  
Electrical Response ◽  
Ice Core

The physicochemical data of extraction with the mixed solvent of NOA and MIBK from hydrochloric acid route phosphoric acid

2019 ◽  
Vol 131 ◽  
pp. 404-409 ◽  
Author(s):  
Weiqing Li ◽  
Ruichao Peng ◽  
Peng Ye ◽  
Xianhe lv ◽  
Tianrong Zhu ◽  
...  
Keyword(s):  
Hydrochloric Acid ◽  
Phosphoric Acid ◽  
Mixed Solvent ◽  
Physicochemical Data

scholarly journals Acid and Enzymatic Hydrolyses of Rice Bran for Bioethanol Production

ALCHEMY ◽  
2018 ◽  
Vol 6 (1) ◽  
pp. 24
Author(s):  
Dewi Yuliani ◽  
Khoirul Achmad Julianto ◽  
Akyunul Jannah
Keyword(s):  
Enzymatic Hydrolysis ◽  
Hydrochloric Acid ◽  
Acid Hydrolysis ◽  
Sulphuric Acid ◽  
Rice Bran ◽  
Dilute Hydrochloric Acid ◽  
Cellulolytic Enzyme ◽  
Bioethanol Production ◽  
By Products ◽  
Sugar Source

<p class="BodyAbstract">Rice bran is one among many agricultural by-products containing ~50-60 wt.% of carbohydrate. The carbohydrate is a prominent sugar source for bioethanol production. The objective of this research was to study bioethanol production from rice bran by acid and enzymatic treatment. The variations of acid used were dilute hydrochloric acid and sulphuric acid, while variations of enzyme used were amylolytic and cellulolytic enzyme. Ethanol production of acid-hydrolyzed rice bran was 24.95±1.61% (v/v) by hydrochloric acid and 29.57±2.04% (v/v) by sulphuric acid. Ethanol produced by enzymatic hydrolysis was quite low i.e. 6.7±0.04%, and 8.86±0.29% (v/v) for amylolytic and cellulolytic hydrolysate, respectively.</p><p class="BodyAbstract"> </p><p>Keywords: Bioethanol, rice bran, acid hydrolysis, enzymatic hydrolysis</p>

scholarly journals Corrosion Behavior of Copper and Carbon Steel in Acidic Media

2014 ◽  
Vol 11 (4) ◽  
pp. 1577-1582
Author(s):  
Baghdad Science Journal
Keyword(s):  
Carbon Steel ◽  
Hydrochloric Acid ◽  
Sulphuric Acid ◽  
Corrosion Behavior ◽  
Effect Of Temperature ◽  
Acidic Media ◽  
Corrosion Rates ◽  
Weight Loss Method ◽  
Acid Environment ◽  
Loss Method

The corrosion behavior of copper and carbon steel in 1M concentration of hydrochloric acid (HCl) and sulphuric acid (H2SO4) has been studied. The corrosion inhibition of copper and carbon steel in 1M concentration of hydrochloric acid (HCl) and sulphuric acid (H2SO4) by Ciprofloxacin has been investigated. Specimens were exposed in the acidic media for 7 hours and corrosion rates evaluated by using the weight loss method. The effect of temperature (from 283 ºK to 333 ºK), pH (from 1to 6), inhibitor concentration (10-4 to 10-2) has been studied. It was observed that sulphuric acid environment was most corrosive to the metals because of its oxidizing nature, followed by hydrochloric acid. The rate of metal dissolution increased with increasing exposure time. Corrosion rates of carbon steel in the acidic media found to be higher.

THE SORPTION OF ACIDS BY WOOL

1949 ◽  
Vol 27b (12) ◽  
pp. 879-889 ◽  
Author(s):  
R. Donovan ◽  
P. Larose
Keyword(s):  
Hydrochloric Acid ◽  
Adsorption Isotherm ◽  
Sulphuric Acid ◽  
Sodium Sulphate ◽  
Langmuir Adsorption Isotherm ◽  
Langmuir Equation ◽  
Recent Application ◽  
Satisfactory Explanation ◽  
Isotherm Equation ◽  
Langmuir Adsorption

The amount of acid sorbed by wool from solutions of sulphuric acid of four different strengths (namely, 0.0505, 0.0339, 0.0182, and 0.0101 molar) and containing sodium sulphate in amounts varying up to 0.16 molar has been determined. It has been found that the presence of the salt has little effect on the quantity of acid sorbed within those limits. The results are analyzed in the light of the theory of Gilbert and Rideal but this theory fails to give a satisfactory explanation of the results obtained. It is possible, however, to explain the results of the authors' experiments on the basis of the recent application of the Donnan equilibrium by Peters and Speakman. The Langmuir adsorption isotherm equation has been applied to data on the absorption of hydrochloric acid and of sulphuric acid by wool. The data appear to fit the Langmuir equation and give, for the maximum combining capacity, values that agree well with those estimated in other ways.

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