Recommended Specifications for Analytical Chemicals - Part 1

Collins, W. D.; Farr, H.V.; Rosin, Joseph; Spencer, Guilford L.; Wichers, Edward

doi:10.1021/ie50198a610

Cited by 3 publications

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“…I11 several experiments, the presence of a substantial quantity of acetic anhydride in the aqueous condensate from the first and second condensers was established by cooling the condensate to -lO°C. to retard the hydrolysis of the anhydride until it could be determined qualltitatively by the "aniline" method (1). Results are shown in Table VI.…”

Section: Discussionmentioning

confidence: 99%

Preparation of Ketene From Glacial Acetic Acid. Methyl Acetate, and Ethyl Acetate

Georgieff¹

1952

Can. J. Chem.

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Laboratory studies were carried out to determine whether nlethyl and ethyl acetates could be pyrolyzed to give yields and conversions to ketene comparable to those obtainable from acetic acid. Acetic acid was pyrolyzed to ketene and water in the presence of 0.33% triethyl phosphate or phosphoric acid catalyst a t 680"-760°C. and 140-160 mm. H g absolute. Maxirnum yield obtained was 80.6y0 and maximum conversion 34.5%. Methyl acetate was cracked to ketene and methanol a t 610°-6850C. and 95-400 mm. absolute, using triethyl phosphate, phosphoric acid, sulphuric acid, dimethyl sulphate, butyl borate, and silica gelboric acid a s catalysts. High yields could be obtained only with phosphates in 2.3% concentration. Maximum yield to ketene, including keterle recovered as acetic acid, was 76% (conversion 31-34Yo). lklaximunl yield to nlethanol was 81.3% (conversion 33-34%). Methyl acetate containing 18% methanol was also cracked but results were poorer. Ethyl acetate, in the presence of 0.33% triethyl phosphate, was pyrolyzed to ketene, ethylene, and water a t 630"-685°C. and 140-190 mm. absolute. Maximum yield of ketene, includi~ig: ketene recovered as acetic acid, was 85.8y0. Maxinlum conversion to ketene was 35.4% and to ketene plus acetic acid 85.7%. Yields to ethylene were nearly quantitative.

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Section: Discussionmentioning

confidence: 99%

Preparation of Ketene From Glacial Acetic Acid. Methyl Acetate, and Ethyl Acetate

Georgieff¹

1952

Can. J. Chem.

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Modified thiocyanogen reagent and method

Lambou

Dollear

1945

Oil Soap

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Summary A general reagent applicable to a wide range of thiocyanogen values and capable of reacting with practically all types of fats and oils has been described. The principal features of the method include rigorous purification of all reagents; replacement of 25% of the volume of glacial acetic acid normally used in preparing the thiocyanogen reagent with an equal volume of carbon tetrachloride; use of finely powdered, dry potassium iodide; increase in the amount of potassium iodide added prior to titration from 1.0 gram to twice the equivalent weight calculated for the volume of standard reagent used; and complete exclusion of water from all reagents and glassware. The value of the modified reagent is attested by data indicating its improved stability, accuracy when applied to pure unsaturated fatty acids, and its general applicability to a wide variety of fats and fat products.

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Recommended Specifications for Analytical Reagent Chemicals

Wichers¹,

Butler²,

Collins³

et al. 1947

Anal. Chem.

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Committee on Analytical Reagents, AMERICAN CHEMICAL SOCIETY THE specifications given below comprise the fourteenth group to be published by the committee since 1925, and the second to supplement and amend those appearing in the twelve earlier publications (1-12), which were contained in the book, "A.C.S. Analytical Reagents", published in 1941.The specifications are intended to serve for reagents to be used in careful analytical work. The limits and tests are based on published work, on the experience of members of the committee in ithe examination of reagent chemicals on the market, and on studies of the tests made by members of the committee as the various items were considered. Suggestions for the improvement of the specifications will be welcomed by the committee.

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Recommended Specifications for Analytical Chemicals - Part 1

Cited by 3 publications

References 0 publications

Preparation of Ketene From Glacial Acetic Acid. Methyl Acetate, and Ethyl Acetate

Preparation of Ketene From Glacial Acetic Acid. Methyl Acetate, and Ethyl Acetate

Modified thiocyanogen reagent and method

Recommended Specifications for Analytical Reagent Chemicals

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