摘要:

Mitraphylline (C21H24O4N2) contains a carbomethoxyl group, and on hydrolysis gives rise to mitraphyllic acid. Spectroscopic evidence shows that the alkaloid contains two chromophores, one characteristic of an oxindole and one corresponding to the grouping CH3OOC—Ć==CH.OR. On treatment with dilute mineral acid the alkaloid gives rise to mitraphyllal (C19H24O3N2), which is a hemiacetal that no longer contains the isolated double bond and the carbomethoxyl group originally present in the alkaloid. Reduction of mitraphyllal by the Wolff–Kishner reaction gives mitraphyllane (C19H26O2N2). The dehydrogenation of mitraphyllal produced 3,4-diethylpyridine and 3-ethyloxindole. The action of lithium aluminum hydride on mitraphylline under mild conditions gave rise to mitraphyllol by reduction of the carbomethoxyl group, and under more vigorous conditions to dihydrodesoxy-mitraphyllol by reduction of the oxindole carbonyl as well. This last product has the properties of an aromatic amine. On the basis of the new experimental evidence, a total structure of mitraphylline is derived

ISSN:0008-4042    

DOI:10.1139/v58-147

出版商:NRC Research Press    

年代:1958

数据来源: NRC

摘要:

The rate of hydrolysis of the sulphate acid ester in unstabilized cellulose nitrates in acetone/water solution at 25 °C. has been studied. The rate of hydrolysis in 90% acetone/water was too slow to produce a measurable increase in acidity during 24 hours. In 99% acetone/water solution the initial hydrolysis was very rapid and was followed by slower hydrolysis which was complete after 24 hours. Similar results were obtained with wood cellulose nitrates.In the case of cotton cellulose nitrates, there was an indication that hydrolysis of the sulphate acid ester decreased as the nitrogen content increased. The rate of hydrolysis of the sulphate acid ester in both cotton and wood cellulose nitrates was very similar to that of the sulphate acid ester in cellulose acetate sulphate.

ISSN:0008-4042    

DOI:10.1139/v58-148

出版商:NRC Research Press    

年代:1958

数据来源: NRC

摘要:

The kinetics of the pyrolysis of ethyl bromide and ethyl bromide-d5have been studied using the toluene carrier gas technique. Variation of the pressure in the range 0.6 to 4.4 cm. Hg reveals what is believed to be a legitimate pressure effect on the first-order rate constants. The Arrhenius rate expressions determined at 4 cm. Hg pressure are:k(ethyl bromide) = 8.5 ± 1.6 × 1012e−52,200±300/RTsec−1(T = 523°–633 °C);k(ethyl bromide-d5) = 2.1 ± 0.4 × 1013e−54,840±300/RTsec−1(T = 531°–635 °C).The differences in the two rate expressions are discussed.

ISSN:0008-4042    

DOI:10.1139/v58-149

出版商:NRC Research Press    

年代:1958

数据来源: NRC

摘要:

The rates of reduction of 3-, 6-, and 7-cholestanone, coprostan-3-one, Δ4- and Δ5-cholesten-3-one, and Δ8(14)-ergosten-3-one with sodium borohydride in isopropanol have been measured. The proportions of α- and β-isomers formed were determined in most cases and the corresponding rates of equatorial and axial reduction obtained. Δ5-Cholesten-3-one and 6- and 7-cholestanone are reduced at a slower rate and Δ5-cholesten-3-one and Δ8(14)-ergosten-3-one at a higher rate than the saturated 3-ketosteroids.

ISSN:0008-4042    

DOI:10.1139/v58-150

出版商:NRC Research Press    

年代:1958

数据来源: NRC

摘要:

Experiments are described on the dehydrogenation of butene-1 in the presence of steam, over three nickel chromite catalysts. These are: (a) pure nickel chromite, (b) nickel chromite pellets impregnated with potash from solution, and (c) a catalyst with potash added before the nickel oxide and chromium sesquioxide are combined. The oxidation state of the catalyst largely affects the products, for overreduction causes disruption of the hydrocarbons. The effect of the potash is to prevent this overreduction and thus to improve selectivity to butadiene. There is a difference between the behavior of catalysts with surface potash (typeb) and those where the potash is distributed through the mass (typec). This difference is explained by the formation of large pores on reduction of type (c) catalysts.

ISSN:0008-4042    

DOI:10.1139/v58-151

出版商:NRC Research Press    

年代:1958

数据来源: NRC

摘要:

In this preliminary series of experiments, calcium sulphate dihydrate has been allowed to crystallize spontaneously from solutions of varying degrees of supersaturation, and induction periods and rate constants have been determined. The effect of crystal area, pH, and accelerators and retarders on this process has been examined. The degree of super-saturation has a direct effect on both the induction period and rate constant. Nucleation is affected markedly by pH. Salts having an ion in common with calcium sulphate function as accelerators. Retarders affect the induction period in proportion to their concentration, but show little, if any, effect on the rate of crystallization. The behavior of the various reagents under the conditions prevailing in these experiments is largely in accord with observations on the behavior of commercial plasters.

ISSN:0008-4042    

DOI:10.1139/v58-152

出版商:NRC Research Press    

年代:1958

数据来源: NRC

摘要:

Phase diagrams for the system KOH–K2CO3–H2O were determined for 25°, 10°, 0°, −10°, −20°, −40°, and −60°. The stable hydrates of potassium hydroxide were the di- and tetra-hydrates; those of potassium carbonate were the sesqui- and hexa-hydrates. No compound formation between KOH and K2CO3was detected.

ISSN:0008-4042    

DOI:10.1139/v58-153

出版商:NRC Research Press    

年代:1958

数据来源: NRC

摘要:

The polarized fluorescence from anthracene sublimation flakes has been measured at 300°, 77°, and 4 °K. A recording spectrometer was used to measure accurately the relative intensity of the two crystal polarizations and also to determine changes in the spectrum between 77° and 4 °K. The polarization ratio (b/a) was found to decrease with increasing wavelength and measurements made at 77° and 4 °K. indicate that there is more than one emitting level and that these have different polarization properties. The fluorescence arises from regions of weak absorption in the crystal and it is suggested that these regions occur in the neighborhood of imperfections. In addition the polarized fluorescence excited from anthracene sublimation flakes containing traces of tetracene has been determined and changes were found in the transfer efficiency between 77° and 4 °K., again suggesting the presence of more than one emitting level. No depolarization of the tetracene fluorescence was observed at low temperatures.

ISSN:0008-4042    

DOI:10.1139/v58-154

出版商:NRC Research Press    

年代:1958

数据来源: NRC

摘要:

A general differential equation is set up for the flow of reactant gases through a catalytic reactor, account being taken of changes in volume as the reaction proceeds and of the possibility that the catalyst surface is not completely available. Integrated solutions are given for three special cases and are presented in graphical form: (1) first-order reaction, the result being applicable whether the surface is completely available or not (Fig. 1); (2) second-order reaction with the surface completely available (Fig. 2); (3) second-order reaction with only a small fraction of the surface available (Fig. 3). The treatment is related to previous treatments of Hulburt, Thiele, and Wheeler.

ISSN:0008-4042    

DOI:10.1139/v58-155

出版商:NRC Research Press    

年代:1958

数据来源: NRC

摘要:

The nature and concentration of the cadmium–containing ions in potassium hydroxide and potassium carbonate solutions have been studied polarographically. The coordination number for the hydroxide–cadmium complex is 4 and its dissociation constant 2×10−10. The coordination number for the carbonate–cadmium complex is 3 and its dissociation constant 6×10−7.

ISSN:0008-4042    

DOI:10.1139/v58-156

出版商:NRC Research Press    

年代:1958

数据来源: NRC