摘要:

An 80° isothermal naphthalene calorimeter analogous to the Bunsen ice calorimeter has been constructed and calibrated. The heat to be measured is made to change the solid/liquid ratio of naphthalene at its melting point, and the resulting volume change is determined by the displacement of mercury in a horizontal capillary tube. The naphthalene chamber is surrounded by the vapor of benzene boiling under an automatically controlled pressure at the melting point of naphthalene. The benzene vapor and the partially frozen naphthalene are separated by an evacuated space.This 80° calorimeter is four times as sensitive as the ice calorimeter and is much more convenient to operate. It is readily adapted to micro work and can be used for fast or slow endothermic or exothermic processes. In the setup described, heats up to about 400 cal. may be measured with a reproducibility of the order of 0.1%. Two different methods of calibration, however, gave "constants" differing by almost 1%. It is thus evident that the instrument must be calibrated as nearly as possible in the way in which it is to be used.

ISSN:1923-4287    

DOI:10.1139/cjr50b-070

出版商:NRC Research Press    

年代:1950

数据来源: NRC

摘要:

Catalytic dehydrogenation of 4-methylquinoline and 6-methylquinoline has been shown to give the corresponding dimethyl-2,2′-biquinolyls. The ultraviolet absorption spectra of the quinolines and biquinolyls have been measured, and the color reaction of the dimethylbiquinolyls with cuprous ion investigated. In all properties examined the dimethylbiquinolyls and biquinolyl behave in a parallel manner.

ISSN:1923-4287    

DOI:10.1139/cjr50b-071

出版商:NRC Research Press    

年代:1950

数据来源: NRC

摘要:

The densities of binary solutions of hydrogen peroxide and water from 0 °C. down to their respective freezing point were measured by the dilatometric method with an estimated precision of ± 0.0003 gm. per ml. Volume changes during solidification were also measured but with lower precision. Solutions containing less than about 50% by weight of hydrogen peroxide expand on freezing whereas more concentrated solutions contract appreciably. Various observations on the phenomenon of supercooling seem to indicate that no solid solutions are formed between the two components. Under certain conditions hydrogen peroxide solutions decompose on melting.

ISSN:1923-4287    

DOI:10.1139/cjr50b-072

出版商:NRC Research Press    

年代:1950

数据来源: NRC

摘要:

Specific gravity, refractivity, viscosity, boiling point, and freezing point data are provided for 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,2-pentanediol and 1,5-pentanediol, in the pure state and in aqueous solution. The observed molar refraction values agreed closely withMrvalues calculated according to Swientoslawski. Lengthening the distance between the hydroxyl substituents increases the specific gravity, refractivity, boiling point, and viscosity, and reduces thermal expansion and isothermal contraction on mixing with water. The order of decreasing effectiveness as freezing point depressants on a weight basis is 1,2-propanediol,leva- 2,3-butanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,2-butanediol, 1,5-pentanediol, and 1,2-pentanediol. Aqueous solutions of all of these glycols exhibit pronounced specific gravity maxima. The glycol concentration at which maximum specific gravity is attained increases with increasing distance between the hydroxyl substituents.

ISSN:1923-4287    

DOI:10.1139/cjr50b-073

出版商:NRC Research Press    

年代:1950

数据来源: NRC

摘要:

A factual test of several possible mechanisms by which alkenes are oxymercurated shows that while addition of mercuric acetate to cyclohexene can be effected smoothly, this 1-acetoxy-2-acetoxymercuricyclohexane cannot be an intermediate in the conversion of cyclohexene in methanolic mercuric acetate to 1-methoxy-2-acetoxymercuricyclohexane. The rate at which the first compound is converted to the second in methanol is much too slow to account for the rate of methoxymercuration. Indeed the behavior of conversion indicates that the first compound reverts in methanol to cyclohexene which then combines with the elements of methoxymercuric acetate. Ionic mechanisms have been shown to be untenable since hydroxymercuration is slower than methoxymercuration although it occurs in a solvent which is much more polar than methanol. A co-ordinative dipole mechanism is suggested which explains the complete retention of configuration during addition as well as the function of boron trifluoride as an accelerator in this reaction.

ISSN:1923-4287    

DOI:10.1139/cjr50b-074

出版商:NRC Research Press    

年代:1950

数据来源: NRC

摘要:

A 40° Bunsen-type isothermal calorimeter has been built and tested. The working substance, benzalacetone, is thermostatted by the vapor of methylal boiling under a constant pressure. An impurity in the benzalacetone makes it necessary to calibrate the instrument in exactly the same way in which it is to be used. Under carefully controlled conditions and with a constant mantle thickness the reproducibility is of the order of 0.2%. With about half the benzalacetone in the solid state, the calorimeter constant was found to be 0.0455 (± 0.0001) gm. of mercury per calorie. This instrument, which can be readily adapted to micro and semimicro work, was designed primarily for the direct determination of the heats and rates of certain enzymatic and bacteriological processes.

ISSN:1923-4287    

DOI:10.1139/cjr50b-075

出版商:NRC Research Press    

年代:1950

数据来源: NRC

摘要:

The heat of the "explosive" crystallization of electrolytically deposited amorphous antimony has been directly determined at 40 °C. in a modified Bunsen-type calorimeter using benzalacetone as the working substance. Correction was made for the amount of antimony trichloride in the deposits and for the crystallization that had taken place between their preparation and explosion. Sixteen runs on exceptionally uniform specimens containing between 4.0 and 7.9% antimony trichloride gave 21.8 cal. per gm. for the heat of explosion, which thus appears to be independent of the antimony trichloride content.

ISSN:1923-4287    

DOI:10.1139/cjr50b-076

出版商:NRC Research Press    

年代:1950

数据来源: NRC

摘要:

not available

ISSN:1923-4287    

DOI:10.1139/cjr50b-077

出版商:NRC Research Press    

年代:1950

数据来源: NRC

摘要:

New polyesters with basic units containing 6, 7, 8, 9, 10, 13, and 14 chain atoms have been prepared fromlevo-2,3-butanediol and ethyl oxalate, ethyl malonate, dimethyl terephthalate, maleic anhydride, succinic, glutaric, adipic, azelaic, and sebacic acids, and frommeso-2,3-butanediol ando-phthalic anhydride. Esterification of 2,3-butanediol with a dibasic acid, or its anhydride, is accompanied by a side reaction, in which butanone-2 and the cyclic methyl ethyl ketal are formed. The purified polyesters, with the exception of the poly-malonate, appear to be composed of regularly recurring acid and diol segments over the molecular weight ranges investigated. Without exception they are amorphous resins or balsams. Polyesters formed from saturated aliphatic dibasic acids become progressively softer as the number of methylene groups in the acid segment increases. The polymeric oxalate, on distillationin vacuo, is converted to a macrocrystalline cyclic monomer.

ISSN:1923-4287    

DOI:10.1139/cjr50b-078

出版商:NRC Research Press    

年代:1950

数据来源: NRC

摘要:

not available

ISSN:1923-4287    

DOI:10.1139/cjr50b-079

出版商:NRC Research Press    

年代:1950

数据来源: NRC