摘要:

The rate of hydrolysis of acetic anhydride at 25 °C. in water (I), in solutions of methyl ethyl ketone (MEK) in water (II), and in solutions of water in MEK (III) have been studied. In I the observation of previous investigators that the velocity constant varies linearly with the initial concentration of acetic anhydride, but for any given initial concentration of acetic anhydride the reaction is pseudomonomolecular, was confirmed and extended. In II the velocity constant is lower than in I and decreases linearly with increasing concentration of MEK, but, again, the reaction is pseudomonomolecular for any given initial concentration of acetic anhydride. An equation and a nomogram that relate the velocity constant to the initial concentration of acetic anhydride, MEK, and water are presented. In III the second-order rate equation must be modified to compensate for the presumed catalytic effect of the hydrogen ion produced by hydrolysis.

ISSN:1923-4287    

DOI:10.1139/cjr50b-080

出版商:NRC Research Press    

年代:1950

数据来源: NRC

摘要:

It has been found that a good yield of nitriles can be obtained by fusing amides with ammonium sulphamate. The method has been applied successfully to simple aliphatic and aromatic amides. There is evidence that the mechanism of this transformation involves reaction between amides and ammonium sulphamate, giving rise to ammonium N-alkoyl or N-aroylsulphamates which rearrange into ammonium bisulphate and nitriles.

ISSN:1923-4287    

DOI:10.1139/cjr50b-081

出版商:NRC Research Press    

年代:1950

数据来源: NRC

摘要:

Certain pentoses and hexoses were determined by measuring spectrophotometrically the yields of furfural and hydroxymethylfurfural obtained on steam distilling with syrupy phosphoric acid. The yields, based on the theoretical recovery, were increased by increasing the temperature and the rate of steam distillation, and by decreasing the amount of sugar. At a steam rate producing 10 ml. per min. of distillate, at 195 °C. externally applied temperature, and with 2 mgm. sugar, the yields of aldehyde were from xylose 91.0%, ribose 74.9%, arabinose 60.6%, rhamnose 55.9%, galactose 20.0%, and glucose 15.5%. As little as 0.1 mgm. of each could be determined in this way, the mean deviation being usually less than ± 3% and the time required less than 10 min. Mixtures of sugars have been separated on a paper strip chromatogram and the individuals determined, without separate extraction, by steam distilling into phosphoric acid.

ISSN:1923-4287    

DOI:10.1139/cjr50b-082

出版商:NRC Research Press    

年代:1950

数据来源: NRC

摘要:

1-Substituted-1-nitroso-3-nitroguanidines on treatment with aqueous potassium hydroxide solution give diazohydrocarbons. This method has been used to prepare diazomethane, diazoethane, diazo-n-propane, diazo-n-butane, diazo-n-pentane, and phenyldiazomethane. Potassium nitrocyanamide has been isolated as a by-product of this reaction.

ISSN:1923-4287    

DOI:10.1139/cjr50b-083

出版商:NRC Research Press    

年代:1950

数据来源: NRC

摘要:

The acetals, 1,1,3-trimethoxybutane, 1,1,3-triethoxybutane, and 1,1,3-tri-n-propoxybutane have been pyrolyzed by passage over a synthetic barium silicate at various temperatures. The yields of the 1-alkoxy-1,3-butadienes isolated from the products of pyrolysis were 80, 45, and 36% respectively. A limited number of catalysts of compositions varying from BaO: 2SiO2to BaO: 10SiO2have been prepared, including the recommended, BaO: 5SiO2. The qualitative effect of catalyst composition of some of these silicates on the yield of 1-methoxy-1,3-butadiene has been described.trans-1-Methoxy-1,3-butadiene has been isolated and characterized by means of reactions with maleic anhydride, and a solution containingcisandtransmolecules has been analyzed and shown to contain 60%cis-1-methoxy-1,3-butadiene.

ISSN:1923-4287    

DOI:10.1139/cjr50b-084

出版商:NRC Research Press    

年代:1950

数据来源: NRC

摘要:

Maximum yields, of about 40%, of RDX were obtained with nitric acid of all concentrations down to 88%, providing the molar ratio of nitric acid to hexamine was sufficiently high. The rate of nitrolysis increased rapidly as the molar ratio of nitric acid to hexamine was increased and continued to do so after the molar ratio was raised above that required for maximum yields. The initial rate was shown to have an upper limit, however, at very high molar ratios. An intermediate in the nitrolysis reaction was isolated and identified as 3,5-dinitrocyclotrimethylenetriamine-1-nitrate (I). (I) was formed rapidly in sufficient quantities of 85 to 91% nitric acid at 0 °C., but had a high rate of decomposition which was independent of both acid concentration and ratio of nitric acid to (I) with 80 to 90% nitric acid. Under nitrolysis conditions some of the hexamine was converted to products not capable of giving RDX, owing apparently to hydrolysis of precursors to (I). The activation energy for the conversion of (I) to RDX was found to be identical with that for the rate controlling step of the conversion of hexamine to RDX. This fact, together with the general kinetic behavior of (I), provided evidence that (I) was a true intermediate and that its reaction to RDX was the rate controlling step in the direct nitrolysis of hexamine. The mechanism of the over-all reaction is discussed in relation to published information concerning the constitution of concentrated nitric acid. Nitracidium ion is believed to be the active nitrolyzing agent.

ISSN:1923-4287    

DOI:10.1139/cjr50b-085

出版商:NRC Research Press    

年代:1950

数据来源: NRC

摘要:

Acetic acid has a harmful effect on the reaction rate and on the yield of RDX at 1 °C. and at 30 °C. for a given nitric acid – hexamine ratio below a certain optimum value. At the optimum, however, the maximum yield of 80% is obtained at both temperatures. The deleterious effect of acetic acid may be explained by assuming that the concentration of the active nitrolyzing agent (nitracidium ion) is decreased by reaction between acetic acid and nitric acid.

ISSN:1923-4287    

DOI:10.1139/cjr50b-086

出版商:NRC Research Press    

年代:1950

数据来源: NRC

摘要:

A number of 3-oxo-2-phenyl-4,4-disubstituted-5-pyrazolones and 3-hydroxy-2-phenyl-4-monosubstituted-5-pyrazolones have been prepared by reacting ethyl di- and monosubstituted malonates with phenylhydrazine in the presence of sodium ethylate. The evidence of an oxo group in position 3 in the disubstituted pyrazolones has been obtained by hydrolyzing 4,4-dibenzyl-3-imino-2-phenyl-5-pyrazolone and identifying the product of the reaction with 4,4-dibenzyl-3-oxo-2-phenyl-5-pyrazolone prepared from dibenzylmalonic ester and phenylhydrazine. A study of the ultraviolet absorption spectra of the pyrazolones has been made and their ionization constants have been determined by potentiometric titrations.

ISSN:1923-4287    

DOI:10.1139/cjr50b-087

出版商:NRC Research Press    

年代:1950

数据来源: NRC

摘要:

The preparation of sodium carboxymethylcellulose from cellulose, sodium hydroxide, and sodium chloroacetate in the presence of water was investigated. The effects of temperature, excess of sodium hydroxide, ratio of water to cellulose, time of mixing, and manner of addition of the reagents were studied. The highest degree of substitution attained was 2.8.

ISSN:1923-4287    

DOI:10.1139/cjr50b-088

出版商:NRC Research Press    

年代:1950

数据来源: NRC

摘要:

The published methods for the determination of the degree of substitution of carboxymethylcellulose were found to be unsatisfactory for samples of high degree of substitution. Two methods were developed: one comprises the removal of the impurities from crude sodium carboxymethylcellulose by dialysis or washing with ethanol and determination of the sodium content; the other is based on the precipitation of cupric carboxymethylcellulose under controlled conditions, purification, and determination of the copper content.

ISSN:1923-4287    

DOI:10.1139/cjr50b-089

出版商:NRC Research Press    

年代:1950

数据来源: NRC