Process Variable Optimization of Kenaf Two-Stage Fractionation Based on Dilute Hydrochloric Acid Followed by Ethanol Organosolv for Component Separation

Kinetics of formation of 2-imino-4-thiazolidone from S-ethoxycarbonylmethylisothiouronium chloride has been studied in aqueous buffers and dilute hydrochloric acid. The reaction is subject to general base catalysis, the β value being 0.65. Its rate limiting step consists in acid-catalyzed splitting off of ethoxide ion from dipolar tetrahedral intermediate. At pH < 2 formation of this intermediate becomes rate-limiting; rate constant of its formation is 2 . 104 s-1.

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Synthesis of the semi-rigid analogues of prothiadene and dithiadene as potential antidepressant and antihistamine agents: 11-[2-(Dimethylaminomethyl)cyclohexylidene]-6,11-dihydrodibenzo[b,e]thiepins and 4-[2-(dimethylaminomethyl)cyclohexylidene]-4,9-dihydrothieno-[2,3-c]-2-benzothiepins

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19851078 ◽

1985 ◽

Vol 50 (5) ◽

pp. 1078-1088 ◽

Cited By ~ 4

Author(s):

Zdeněk Polívka ◽

Jiří Holubek ◽

Emil Svátek ◽

Jan Metyš ◽

Miroslav Protiva

Keyword(s):

Hydrochloric Acid ◽

Ir Spectrum ◽

Title Compound ◽

Dilute Hydrochloric Acid ◽

Amino Alcohols ◽

Geometric Isomers ◽

Pharmacological Testing

Reaction of dibenzo[b,e]thiepin-11(6H)-one with 2-(dimethylaminomethyl)cyclohexylmagnesium chloride gave a mixture of stereoisomeric amino alcohols IX from which four homogeneous bases (IXa to IXd) were separated by chromatography. Dehydration of these compounds with boiling dilute hydrochloric acid afforded mixtures of racemic geometric isomers of the title compound VII, which were separated by crystallization. To the prevailing less polar base VIIa (E)-configuration was assigned on the basis of the IR spectrum. Using a similar procedure, thieno[2,3-c]-2-benzothiepin-4(9H)-one gave mixture of amino alcohols X from which three homogeneous stereoisomers X-A to X-C were isolated. Their dehydration resulted in both expected racemic geometric isomers VIII-A and VIII-B. Pharmacological testing proved the character of an antidepressant for the semi-rigid analogue of dithiadene VIII.

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An alternative method for assaying cerebrospinal fluid protein in the presence of methotrexate.

Clinical Chemistry ◽

10.1093/clinchem/34.10.2091 ◽

1988 ◽

Vol 34 (10) ◽

pp. 2091-2092 ◽

Cited By ~ 1

Author(s):

L M Kasper ◽

W R Moorehead ◽

T O Oei ◽

M Markanich

Keyword(s):

Cerebrospinal Fluid ◽

Hydrochloric Acid ◽

Trichloroacetic Acid ◽

Dilute Hydrochloric Acid ◽

Constant Amount ◽

Manual Method ◽

Turbidimetric Method ◽

Methotrexate Concentration ◽

Cerebrospinal Fluid Protein ◽

Positive Interference

Abstract Therapeutic concentrations of methotrexate can cause significant positive interference in cerebrospinal fluid (CSF) protein values when assayed in the Du Pont aca. Conversely, our modified turbidimetric method, in which trichloroacetic acid (TCA) plus a sample blank containing dilute hydrochloric acid is used in place of TCA, exhibits little or no interference from methotrexate. This was verified by assaying solutions that contained a constant amount of protein (approximately 430 mg/L) and various amounts of methotrexate (0.0-2.3 x 10(-4) mol/L) by both the Du Pont aca and the manual turbidimetric method. As expected, the aca results showed increasing protein values with increasing methotrexate, whereas the manual method gave results approximating the expected protein value irrespective of the methotrexate concentration.

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Composite Oxidizing Agents Generation Using Electrolysis of Dilute Hydrochloric Acid

Journal of Korean Society of Environmental Engineers ◽

10.4491/ksee.2016.38.6.329 ◽

2016 ◽

Vol 38 (6) ◽

pp. 329-333 ◽

Cited By ~ 1

Author(s):

Shin-Young Kang ◽

Jong-Hun Park ◽

Sang-Hyoun Kim

Keyword(s):

Hydrochloric Acid ◽

Dilute Hydrochloric Acid ◽

Oxidizing Agents

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Acid and Enzymatic Hydrolyses of Rice Bran for Bioethanol Production

ALCHEMY ◽

10.18860/al.v6i1.6767 ◽

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

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. Keywords: Bioethanol, rice bran, acid hydrolysis, enzymatic hydrolysis

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Salts of Sulfated Oleic Acid Amides as Acid Corrosion Inhibitors

Chemistry and Technology of Fuels and Oils ◽

10.32935/0023-1169-2021-625-3-36-38 ◽

2021 ◽

Vol 625 (3) ◽

pp. 36-38

Author(s):

E. K. Aminova ◽

◽

V. V. Fomina ◽

Keyword(s):

Oleic Acid ◽

Sulfuric Acid ◽

Hydrochloric Acid ◽

Aqueous Solutions ◽

Carboxylic Acids ◽

Ammonium Salt ◽

Dilute Hydrochloric Acid ◽

Corrosion Inhibitors ◽

Acid Corrosion ◽

Protective Ability

This work is a continuation in a series of studies on the preparation of acid corrosion inhibitors based on carboxylic acids. A method of synthesis of acid corrosion inhibitors based on oleic acid amides has been developed. Several syntheses have been carried out to increase its inhibitory properties. The substances were obtained in several stages. At the first stage, amino alcohols were added to the ОA, then the resulting compounds were sulfonated with sulfuric acid. To expand the field of various inhibitors, reactions with bases are produced. As a result, salts of sulfated amides of oleic acid synthesized with amino nitrates, sulfuric acid and aqueous solutions of bases were formed. To establish the effectiveness of the compounds obtained, the protective ability in dilute hydrochloric acid was evaluated. It is established that some of the obtained substances exhibit the corresponding properties of inhibitors. In this case, the most effective is the ammonium salt of sulfated diethanolamide oleic acid.

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Liquid Chromatographic Method for Identity, Assay, and Content Uniformity of Five Tricyclic Drugs

Journal of AOAC INTERNATIONAL ◽

10.1093/jaoac/68.2.168 ◽

1985 ◽

Vol 68 (2) ◽

pp. 168-171

Author(s):

Edward G Lovering ◽

Normand Beaulieu ◽

Robert C Lawrence ◽

Roger W Sears

Keyword(s):

Hydrochloric Acid ◽

Active Ingredient ◽

Dilute Hydrochloric Acid ◽

Chromatographic Method ◽

Internal Standard ◽

Peak Height ◽

Content Uniformity ◽

Liquid Chromatographic Method ◽

Liquid Chromatographic ◽

Better Than

Abstract A liquid chromatographic (LC) procedure has been developed for the assay, content uniformity, and identification of single active ingredient solid and liquid formulations of amitriptyline, chlorpromazine, imipramine, thioridazine, and trifluoperazine. The drugs are extracted from their formulations with methanol or dilute hydrochloric acid, and identified by comparison of retention times with those of known standards; drugs are quantitated against these standards with rf/-norephedrine hydrochloride as the internal standard. The precision of replicate injections is better than 2.5% for peak area and better than 1% for peak height. The precision of triplicate determinations of tablet composites is better than 2.2%.

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