摘要:

not available

ISSN:0008-4042    

DOI:10.1139/v54-073

出版商:NRC Research Press    

年代:1954

数据来源: NRC

摘要:

Evidence for the existence of the ester form of the sulphate in unstabilized cellulose acetate has been examined by ion exchange studies on precipitated and fibrous cellulose acetate. The equilibrium reached during ion exchange is affected by the pH and by the concentration of the salt solution used. The thermal stability of the ester is shown to vary inversely with the sulphate content. A study has been made of the accuracy of the various analyses involved.

ISSN:0008-4042    

DOI:10.1139/v54-074

出版商:NRC Research Press    

年代:1954

数据来源: NRC

摘要:

In the absence of addition agent, the cathode polarization during initial electrolysis of copper from a solution of acid copper sulphate rose almost instantaneously from zero to approximately the steady state polarization. When gelatin was present in the electrolyte, the polarization generally increased to a maximum,Pmax, (in timetmax) then decreased to a minimum,Pmin, (in-timetmin) beyond which it increased to the steady state value,Ps. Generally,Pmaxincreased to a steady value with an increase in the time,T0, the electrode was in contact with the electrolyte before electrolysis was begun. At low, moderate, and high current densities respectively,tmaxincreased continuously, passed through a maximum, and decreased continuously withT0.The behavior oftminapproximately paralleled that oftmax. The polarization was linear in the logarithm of the current density;tmaxandtmindecreased with increase in current density. The polarization values increased andtmaxdecreased, with increase in gelatin concentration. Increase of temperature had approximately the same effect as decrease in current density. With both chloride and gelatin present,Pmaxwas practically independent ofT0and chloride concentration, whilePminandPsshowed minimum values at about 2 mgm./l. chloride.

ISSN:0008-4042    

DOI:10.1139/v54-075

出版商:NRC Research Press    

年代:1954

数据来源: NRC

摘要:

It is shown that metallic indium adsorbs mercury vapor quite rapidly after a short induction period. It is suggested that indium may be found useful in removing traces of mercury vapor from vacuum systems.

ISSN:0008-4042    

DOI:10.1139/v54-076

出版商:NRC Research Press    

年代:1954

数据来源: NRC

摘要:

The hydrogen-abstraction reactions of methyl and ethyl radicals from diethyl ketone have been studied in the temperature range 25 to 160 °C. Azomethane and azoethane were used as photochemical sources of methyl and ethyl radicals. The activation energies found were 7.0 and 7.6 kcal., respectively, for the reactions:If the combination of both methyl and ethyl radicals is assumed to occur at every collision, the steric factors for the two reactions areE1 = 7.4 × 10−4,E2 = 7.1 × 10−4.

ISSN:0008-4042    

DOI:10.1139/v54-077

出版商:NRC Research Press    

年代:1954

数据来源: NRC

摘要:

Chlorobenzene-2,4-disulphonates (II), -disulphones (IV), and -disulphonamides (V) have been prepared from chlorobenzene-2,4-disulphonyl chloride (I). The properties and reactions of I–V have been compared with those of related derivatives ofp-chlorobenzenesulphonic acid and phenoxybenzene-4,4′-disulphonic acid.

ISSN:0008-4042    

DOI:10.1139/v54-078

出版商:NRC Research Press    

年代:1954

数据来源: NRC

摘要:

Treatment of gelsemine with cyanogen bromide produced N-cyano-norgelsemine which on catalytic hydrogenation gave rise to N-cyanodihydro-N-norgelsemine, identical with the product of the reaction of cyanogen bromide with dihydrogelsemine. N-Cyanodihydro-N-norgelsemine was hydrolyzed with hydrochloric acid to dihydro-N-norgelsemine which readily formed a mono- or a dibenzoyl derivative according to the conditions, and ap-toluenesulphonamide. The action of phosphorus pentachloride on the monobenzoyl derivative gave rise to N-benzoylchlorodihydro-N-norgelsemine, hydrolyzable by hydrochloric acid to chlorodihydro-N-norgelsemine. This chloro compound was converted by the action of formaldehyde and formic acid to chlorodihydrogelsemine, identical with the product of the action of phosphorus pentachloride on dihydrogelsemine. Chlorination of dihydrogelsemine with chlorine produced dichlorogelsemine.

ISSN:0008-4042    

DOI:10.1139/v54-079

出版商:NRC Research Press    

年代:1954

数据来源: NRC

摘要:

A study has been made of the conditions affecting the isolation of a lignin fraction by a procedure involving a moderate temperature catalytic hydrogenation of pre-extracted aspen wood meal. The effect of varying the initial hydrogen pressure, the catalyst, the time and maximum temperature of reaction, and the nature and acidity of the suspending medium were studied. The weight of the residual pulp, the effectiveness of lignin removal, the weight and methoxyl content of the resulting chloroform-soluble fraction containing the lignin, and the yields of vanillin and syringaldehyde obtained by the alkaline nitrobenzene oxidation of this same fraction were the factors serving as the bases for comparison.Initial hydrogen pressures greater than 500 p.s.i.g. were not required, although below this value there was some loss of efficiency. Neither the use of water or dioxane alone was satisfactory as a suspending medium, but the mixed aqueous-organic medium was required to remove the released lignin. Considering the resultant slight acidity of the reaction product, it is suggested that in such an isolation two separate stages are involved: that of the water functioning to wet and permeate the wood and serve as the acidic medium and that of the organic solvent phase functioning to remove the liberated lignin after the hydrolytic cleavage.Data are presented and interpreted to indicate the existence of a lignin-carbohydrate complex which is cleaved under the conditions of catalytic hydrogenation. Under the conditions of these experiments practical temperatures for lignin removal are in the range 170 – 180 °C. for an aqueous-organic solvent medium, but some thirty degrees lower for an 85% acetic acid medium. Although it has been possible to isolate all the lignin, with good methoxyl recovery, consistently no more than approximately fifty per cent of the required aldehydes is obtainable on oxidation. The increasing value of the syringaldehyde – vanillin ratio with increasing temperature is due to a decreased vanillin yield.Indications are that the use of copper chromium oxide may be preferred over Raney nickel as a catalyst for this isolation procedure.

ISSN:0008-4042    

DOI:10.1139/v54-080

出版商:NRC Research Press    

年代:1954

数据来源: NRC

摘要:

1,5:3,6-Dianhydro-2,4-O-methylene-D-glucitol has been synthesized by two wholly independent routes. The methylene acetal bridge was found to be stable in hot water and dilute aqueous acid and thus differs from the methylene bridges in 1,4:3,6-dianhydro-2,5-O-methylene-D-mannitol and in theD-iditol analogue of the latter compound. It is suggested that this difference may be due to the ease of folding of the glucitol derivative as compared to the rigidity of the mannitol and iditol structures.

ISSN:0008-4042    

DOI:10.1139/v54-081

出版商:NRC Research Press    

年代:1954

数据来源: NRC

摘要:

not available

ISSN:0008-4042    

DOI:10.1139/v54-082

出版商:NRC Research Press    

年代:1954

数据来源: NRC