Rubber. XVIth Communication. The Method of A. R. Kemp for the Determination of the Iodine Number of Rubber

1934 ◽  
Vol 7 (3) ◽  
pp. 587-590
Author(s):  
Rudolf Pummerer ◽  
Hermann Stark
Keyword(s):  
Acetic Acid ◽  
Iodine Number ◽  
Carbon Disulfide ◽  
Glacial Acetic Acid ◽  
Chloroform Solution ◽  
Precise Information ◽  
Iodine Chloride ◽  
The Subject ◽  
Accessible Form

Abstract In a communication of Pummerer and Mann in 1929 on the determination of the iodine number of rubber by means of iodine chloride in chloroform solution, Fisher and Gray were erroneously mentioned as the originators of the method, because of the fact that these authors were the first to publish the method in accessible form. The fact was overlooked that Fisher and Gray state in a footnote that the method was not their own but was that of A. R. Kemp of the Bell Telephone Laboratories. We are greatly indebted to Kemp for calling to our attention the error, which also appears in our XIVth Communication. The first paper of Kemp on the subject appeared a year later, and contains precise information. Kemp worked with a solution of iodine chloride in glacial acetic acid and a solution of rubber in carbon disulfide at 0° C., and as long ago as 1927 he showed that rubber obtained by extraction of crepe with petroleum ether (b. p. 35–60° C.), and precipitation with alcohol according to the method of Weber, Caspari and Feuchter, gave very satisfactory iodine numbers of 99.43–99.76 per cent of the theoretical value. At 15–20° C. disturbing effects of substitution occurred.

Determination of the Iodine Number of Raw Rubber

1929 ◽  
Vol 2 (3) ◽  
pp. 362-364
Author(s):  
Adolf Gorgas
Keyword(s):  
Acetic Acid ◽  
Iodine Number ◽  
Carbon Disulfide ◽  
Convenient Method ◽  
The State ◽  
Hydrogen Halide ◽  
Potassium Iodate ◽  
Substitution Reactions ◽  
Iodine Chloride

Abstract In the course of an investigation dealing with the nature of the state of unsaturation of raw rubber, it became necessary to have available a precise and convenient method for determining the iodine number of raw rubber. Though iodine reacts only slowly with unsaturated compounds, chlorine and bromine form both addition and substitution products. In the substitution reactions, the hydrogen halide is evolved, and by addition of potassium iodate, e.g., in the method of MacIlhiney, it is possible to determine the hydroden halide formed and thus the quantity of halogen substituted. In all methods, however, where extensive substitution as well as addition take place, the results are variable and uncertain. Accordingly in the chemistry of fats where the iodine number is of the greatest importance, iodine halides have been used for determining the iodine number, for under certain conditions there is very little substitution. Thus Hübl, Waller and Wijs solutions contain iodine chloride and Hanus solution contains iodine bromine. The Hanus method has in fact to a great extent replaced all other methods For determining the iodine number of rubber, the Wijs method in the form in which it was modified by Kemp is probably used more than any other. In the Kemp method about 0.1 gram of rubber is swollen in 75 cc. of carbon disulfide, and is then allowed to react for 2 hours at 0° C. with 25 cc. of Wijs solution, i.e., 0.5 N iodine chloride in acetic acid.

Determination of Piperazine in Formulations by Nonaqueous Titration

1963 ◽  
Vol 46 (6) ◽  
pp. 1060-1062
Author(s):  
R B Maybury ◽  
R Payfer
Keyword(s):  
Aqueous Solution ◽  
Acetic Acid ◽  
Perchloric Acid ◽  
Glacial Acetic Acid ◽  
Chloroform Solution ◽  
New Method ◽  
Alternative Procedure ◽  
Good Agreement

Abstract A new method is presented for the nonaqueous titration of piperazine in formulations in which the piperazine base is first brought into aqueous solution, and the solution is made strongly alkaline and extracted with chloroform. The chloroform solution of piperazine is then titrated with acetous perchloric acid to alpha-naphthol benzein indicator. The procedure is rapid, shows good agreement with other methods, and is applicable to most kinds of piperazine formulations. An alternative procedure for piperazine adipate, citrate, or tartrate in powders is given, in which the compound is dissolved and titrated directly in glacial acetic acid.

Reverse Phase Liquid Chromatographic Determination of Chlorophacinone and Diphacinone in Bait Formulations

1982 ◽  
Vol 65 (4) ◽  
pp. 927-929
Author(s):  
Brian R Bennett ◽  
Gregory S Grimes
Keyword(s):  
Acetic Acid ◽  
Glacial Acetic Acid ◽  
Chromatographic Determination ◽  
Reverse Phase ◽  
Target Concentration ◽  
External Standard ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Liquid Chromatographic

Abstract Chlorophacinone and diphacinone are extracted at the 0.005% level from grain or paraffinized baits with glacial acetic acid. The target concentration is 0.01 mg/mL. The filtered supernate is chromatographed on a Partisil PXS ODS10/25 liquid chromatography column with premixed and degassed glacial acetic acid-tetrahydrofuran-water (14 + 2 + 9) and detected at 288 nm. The concentration is calculated by using an external standard. The recovery from spiked samples averaged 96.6% for both analytes. The response is linear from 0.001 to 0.040 mg/mL. The coefficient of variation of within-day replicates ranged from 1.1 to 2.5%.

Method for the accurate determination of specific rotation. Specific rotation of valine and leucine

1969 ◽  
Vol 47 (15) ◽  
pp. 2739-2746 ◽  
Author(s):  
J. C. MacDonald
Keyword(s):  
Acetic Acid ◽  
Glacial Acetic Acid ◽  
Optical Rotation ◽  
Accurate Determination ◽  
Computer Calculation ◽  
Specific Rotation ◽  
Best Fit

The optical rotation of various concentrations of L-valine and L-leucine, dissolved in glacial acetic acid, or 5 or 6 M HCl, was measured with a photoelectric polarimeter at the nominal wavelengths 589, 578, 546, 436, and 365 nm and temperatures of 20, 25, and 30 °C. The specific rotation for any one wavelength, solute, and solvent could be defined by the equation [α]λT = A(1 + D(T − 25)) + BC, where T is temperature in °C, C is concentration in grams of solute per 100 ml of solution, and A, B, and D are constants. The best fit values of the constants were determined by computer calculation and are listed. Constants are also given for calculating a specific rotation based on grams of solute per 100 g of solution.

Determination of acetaldehyde in glacial acetic acid by gas chromatography

1974 ◽  
Vol 46 (11) ◽  
pp. 1584-1584 ◽  
Author(s):  
Harold J. Rhodes ◽  
David W. Bode ◽  
Martin I. Blake
Keyword(s):  
Gas Chromatography ◽  
Acetic Acid ◽  
Glacial Acetic Acid

Bromination of Acridine

2018 ◽  
Vol 71 (4) ◽  
pp. 285
Author(s):  
Graham S. Chandler ◽  
Wolfgang H. F. Sasse
Keyword(s):  
Acetic Acid ◽  
Sulfuric Acid ◽  
Quantitative Determination ◽  
Glacial Acetic Acid ◽  
Tiny Amount ◽  
Concentrated Sulfuric Acid

The quantitative determination of the products of bromination of acridine in concentrated sulfuric acid and glacial acetic acid is described. In both cases, the only monobromo products were the 2- and 4-substituted compounds. With sulfuric acid, the 4-isomer predominates whereas in acetic acid, the 2-isomer is predominant. This work expands substantially on the tiny amount of previous work on halogenation of dibenzo-annelated pyridines.

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