摘要:

It has been found that dialkylchloramines can be nitrated to dialkylnitramines either in nitric acid or, better, in a mixture of nitric acid and acetic anhydride. Electropositive chlorine also is formed during this nitration. This formation supports a postulate that chloride-catalyzed nitration of secondary amines proceeds via the chloramine as an intermediate. Since electropositive chlorine is regenerated, the catalyzed nitration can be considered as a self-sustaining chain reaction. Examination of the by-products resulting from nitration of chloramines indicates that chloramine nitration, and not chloramine formation, is the rate-controlling step in the catalyzed nitration.

ISSN:1923-4287    

DOI:10.1139/cjr48b-026

出版商:NRC Research Press    

年代:1948

数据来源: NRC

摘要:

The yield of purified dioctylnitramine from di-n-octylammonium chloride is low and the crude nitration product is badly contaminated with by-products which contain halogen. Since dioctylamine can be nitrosated, acetylated, chlorinated, andp-toluenesulphonated with ease it is considered that the low yield of nitro compound is owing to decomposition of the dioctylchloramine which is intermediate during the nitration process. A mechanism for this decomposition is suggested on the basis of the products isolated from treatment of the chloramine with hydrogen chloride, acetyl chloride, acetic acid, or acetic anhydride.

ISSN:1923-4287    

DOI:10.1139/cjr48b-027

出版商:NRC Research Press    

年代:1948

数据来源: NRC

摘要:

A method has been devised for conversion of alkyldichloramines to the corresponding nitramines. Six examples have been described. The reaction seems to proceed via the chloronitramine. This compound may be converted to the nitramine by hydrolysis with evolution of hypochlorous acid. An intramolecular fission of hydrogen chloride seems in one case to yield, alternatively, the nitrimine. The structures of diisopropylnitramine and di-n-octylnitramine have been confirmed by synthesis from the primary nitramines.

ISSN:1923-4287    

DOI:10.1139/cjr48b-028

出版商:NRC Research Press    

年代:1948

数据来源: NRC

摘要:

The reactionhas been found to be reversible in acetic anhydride. Analysis for electropositive chlorine and for nitric acid in this reacting system indicates that consumption of NO3−and production of Cl+passes through a maximum after which nitric acid is regenerated and electropositive chlorine disappears. This phenomenon has been interpreted as an initial formation of chlorine acetate (or other chlorine ester) which then decomposes to give elemental chlorine. The increased demand for hydrogen chloride then shifts the equilibrium toward regeneration of nitric acid. The reaction has been found to be second order in its kinetics, with an activation energy of about 8000 cal. It is probably not the rate-controlling step in the catalyzed nitration, except perhaps where such nitration is easy and efficient. When nitration is difficult the electropositive chlorine tends to accumulate. When it becomes elemental chlorine, it is ineffective for nitration catalysis and is destructive to the amine. The catalysts acetyl chloride and zinc chloride have been studied. Electropositive chlorine formation occurs at the same rate with acetyl chloride as with hydrogen chloride. Zinc chloride, on the other hand, has been found to generate the maximum amount of electropositive chlorine immediately. This indicates that zinc chloride would be a good catalyst for easily nitrated amines but less efficient for amines which react more slowly, since the chlorine acetate not consumed by chloramination would decompose to give the destructive elemental chlorine. No mono-, di-, or trichloroacetic acids, nor perchloric acid, could be detected in aged reaction systems initially hydrogen chloride – nitric acid – acetic anhydride.

ISSN:1923-4287    

DOI:10.1139/cjr48b-029

出版商:NRC Research Press    

年代:1948

数据来源: NRC

摘要:

Simple distillation with hydrobromic acid converted xylose to furfural in approximately 93% yield. Addition of sodium bromide to hydrobromic acid increased the rate of formation of furfural but did not increase the final yield. Twenty-three per cent hydrobromic acid was slightly more destructive towards furfural than 12% hydrochloric acid. Approximately 23% hydrobromic acid was found to be the best concentration for pentose determination; higher concentrations gave lower yields of furfural while lower concentrations gave slightly higher yields but required greatly extended periods of distillation. For determination of pentoses and pentosans, hydrobromic acid has no advantage over hydrochloric acid now in general use.

ISSN:1923-4287    

DOI:10.1139/cjr48b-030

出版商:NRC Research Press    

年代:1948

数据来源: NRC

摘要:

The previous observation by Stillings and Browning that methylfurfural and hydroxymethylfurfural do not interfere with the photocolorimetric determination of furfural with aniline has been confirmed. The color of the furfural – aniline acetate compound was stabilized satisfactorily by oxalic acid and sodium chloride; the addition of disodium phosphate brought about minimum transmittance. Recoveries of furfural distilled from 12% hydrochloric acid were 99.0 and 99.7% as measured by the photocolorimetric and excess bromine titration methods respectively. Xylose was converted to furfural in 90.6% yield by simple distillation with 12% hydrochloric acid saturated with sodium chloride. Rapid steam distillation increased the recovery to 91.6%. Dextrose, levulose, cellulose and rhamnose gave apparent furfural yields by the excess bromine titration method but negative results with the photocolorimetric method. The two methods were applied to 13 plant residues whose furfural contents ranged from more than 30% in 'Beewing' wheat bran to less than 5% for peat. The results obtained by the photocolorimetric method, regarded as being the true furfural contents, are 2 to 3% lower than those obtained by the titration method.

ISSN:1923-4287    

DOI:10.1139/cjr48b-031

出版商:NRC Research Press    

年代:1948

数据来源: NRC

摘要:

Holocelluloses have been prepared in substantially quantitative yields from extractive-free straws of wheat, oats, barley, rye, and flax by acid chlorite treatments. Estimation of the pentosan, uronic acid anhydride, Cross and Bevan cellulose, and acetyl contents of the recovered holocelluloses showed that little loss of carbohydrate material had occurred during isolation. Lignin contents of the holocelluloses from the various straws varied between 2.5 and 3.5%. Extension of the chlorite treatments beyond the number required to isolate the holocellulose resulted in only minor diminution of lignin but caused considerable loss of carbohydrate material. Mild delignifying treatments of crude holocellulose with hypochlorite (acid and neutral), hypochlorite and sulphite extraction, bromine, and alcoholic ethanolamine had effects similar to those of acid chlorite. The major portion of protein in the straws was removed by acid chlorite. The isolated holocellulose contained more ash than the original straws.

ISSN:1923-4287    

DOI:10.1139/cjr48b-032

出版商:NRC Research Press    

年代:1948

数据来源: NRC

摘要:

The genusSerratiamay be divided into three groups on the basis of three characteristic fermentations found under anaerobic conditions. The first group, comprised of all strains ofS.marcescens,S.anolium, andS.indicatested and one strain namedS.kielensis, dissimilates glucose as follows: C6H12O6 → CH3CHOHCHOHCH3 + HCOOH + CO2. The second group, containingS.plymouthensisand some unnamed strains, dissimilates glucose according to the equation: C6H12O6 → CH3CHOHCHOHCH3 + 2CO2 + H2. The third group containing only the most typical strain ofS.kielensiscarries out the reaction: C6H12O6 + 2H2O → 2CH3COOH + 2CO2 + 4H2. These reactions account for approximately one-half of the glucose utilized, the remainder being accounted for chiefly by the ethanol and lactic acid fermentations which are found in varying proportions with different strains. All strains form some succinic acid, probably by carbon dioxide fixation. Under aerobic conditions carbon dioxide formation is stimulated, chiefly at the expense of formic acid with organisms of the first group, while hydrogen formation by organisms of the second and third groups is depressed.

ISSN:1923-4287    

DOI:10.1139/cjr48b-033

出版商:NRC Research Press    

年代:1948

数据来源: NRC

摘要:

The Paneth–Rice free radical detection technique has been applied to the study of reactions of hydrogen atoms, produced by the discharge tube method, with two compounds, acetone and dimethyl mercury. Bismuth has been demonstrated to be a satisfactorily stable 'mirror metal' for the purpose, although some evidence was noted for the formation of a short-lived hydride of this metal under the adopted experimental conditions. A method has been devised for the preparation of radioactive bismuth mirrors of known specific activity, utilizing Bi210('Radium E'), obtained from uranium extraction residues, as the tracer. The hydrogen atom – acetone reaction system gave no evidence in the present work for the formerly postulated existence of free alkyl radicals. However, conclusive positive results were obtained in the case of the dimethyl mercury reaction. Studies in which the methane–ethane ratio in the products of the latter reaction was compared in presence and absence of the radical-sensitive mirror have further supported a previously proposed free radical mechanism.

ISSN:1923-4287    

DOI:10.1139/cjr48b-034

出版商:NRC Research Press    

年代:1948

数据来源: NRC

摘要:

A kinetic study of popcorn formation in solutions of butadiene in styrene indicates that the free radicals necessary for the polymerization are produced initially on the seed by decomposition of hydroperoxides. A further reaction involving opening of double bonds in reacting chains leads also to radical formation. The function of butadiene is to supply double bonds to the chain and thus enable branching to occur. The growth rate varies with the molar ratio of butadiene: styrene in the seed, showing an optimum value at 0.27 M/M. Benzoyl peroxide inhibits the reaction somewhat, at the same time catalyzing the normal formation of soluble polymer. Popcorn initiation in unseeded samples is catalyzed by small concentrations of peroxides, larger concentrations producing no further effect. An optimum butadiene: styrene ratio of 0.1 M/Mexists in popcorn initiation. The reaction apparently does not take place on the surface of the vessel. Traces of nitric oxide strongly inhibit popcorn formation in seeded and unseeded samples. The proliferative activity of popcorn seed is reduced by treating it with nitric oxide. A quantitative treatment of the mechanism is given.

ISSN:1923-4287    

DOI:10.1139/cjr48b-035

出版商:NRC Research Press    

年代:1948

数据来源: NRC