摘要:

Partition on Celite columns, using both elution and extrusion techniques, was found to be a convenient and satisfactory chromatographic method for preparative or analytical work involving carbohydrates and their derivatives. The method is superior to other chromatographic procedures for carbohydrates in resolution of mixtures; cost, ease, and speed of operation; yield and purity of products; and range of applicability. To illustrate these advantages a number of specific examples are given involving partially methylated derivatives ofD-glucose andD-xylose and isolation of products from reaction mixtures.

ISSN:0008-4042    

DOI:10.1139/v56-175

出版商:NRC Research Press    

年代:1956

数据来源: NRC

摘要:

The effects of various complexing agents on the homogeneous reduction of mercuric salts by molecular hydrogen in aqueous solution were determined. In all cases the kinetics suggest that the rate-determining step is a bimolecular reaction between a mercuric ion or complex and a hydrogen molecule, probably leading to the formation of an intermediate mercury atom. The reactivity of various mercuric complexes was found to decrease in the following order: HgSO4 > Hg++ > HgAc2, HgPr2 > HgCl2 > HgBr2 > Hg(EDA)2++. Addition of anions such as OH−, CO3=, Ac−, Pr−, and Cl−, in excess of the amounts required to form stable mercuric complexes, was found to increase the rate. An interpretation of these effects is given.

ISSN:0008-4042    

DOI:10.1139/v56-176

出版商:NRC Research Press    

年代:1956

数据来源: NRC

摘要:

By comparison of the infrared absorption spectrum of methyl acetate with the spectra of three deuterium substitution products, it has been possible to assign the bands in the 3100–2800 cm.−1and 1500–1300 cm.−1regions of methyl acetate to vibrations localized in the individual methyl groups. Bands characteristic of the individual trideuteromethyl groups are also identified between 2300 and 2000 cm.−1. The C=O stretching frequency is observed to shift to lower frequency with increasing deuteration. The spectra in the range 1300–700 cm.−1are also reported.

ISSN:0008-4042    

DOI:10.1139/v56-177

出版商:NRC Research Press    

年代:1956

数据来源: NRC

摘要:

The infrared absorption spectrum of ethyl acetate has been compared with the spectra of seven derivatives deuterated in the methyl and methylene groups. In the region 3500–1300 cm.−1most of the bands can be assigned to vibrations localized in the individual groups. Absorption characteristic of the trideuteromethyl and dideuteromethylene groups can be recognized between 2300 and 2000 cm.−1. The C=O stretching vibration shows progressive displacement to lower frequency with increasing deuteration. The spectra in the range 1300–700 cm.−1are also reported.

ISSN:0008-4042    

DOI:10.1139/v56-178

出版商:NRC Research Press    

年代:1956

数据来源: NRC

摘要:

Lithium nitrate does not form solid alcoholates at 25 °C. The hydrate consisting of one molecule of nitrate to half a molecule of water, which is claimed to exist by Donnan and Burt, appears not to exist. Not only does this half hydrate not appear on the 25° isotherm but it cannot be detected dilatometrically at any temperature.

ISSN:0008-4042    

DOI:10.1139/v56-179

出版商:NRC Research Press    

年代:1956

数据来源: NRC

摘要:

Diphenylalkylthiopseudourea hydrohalides and dichlorodiphenylalkylthiopseudourea hydrohalides are formed when the corresponding thiourea is treated with an alkyl halide. The thiourea is prepared by the addition of hydrogen sulphide to the corresponding cyanamide compound. The hydrohalides are unstable in the presence of alkali.

ISSN:0008-4042    

DOI:10.1139/v56-180

出版商:NRC Research Press    

年代:1956

数据来源: NRC

摘要:

The periodate–permanganate reaction with methyl oleate and triolein has been studied in media containing a variety of organic solvents. The oxidation proceeded favorably in media containing tertiary butanol or pyridine and conditions have been found which permit the quantitative analysis of unsaturated lipids.

ISSN:0008-4042    

DOI:10.1139/v56-181

出版商:NRC Research Press    

年代:1956

数据来源: NRC

摘要:

The kinetics of the oxidation of uranium(IV) by molecular oxygen in aqueous perchloric acid solution were studied. Over a considerable range of conditions, the results are fitted approximately by the rate law:−d[UIV]/dt = k[UIV] [O2]/[H+], wherek ≈ 2 × 1014exp[−22,000/RT]sec.−1. The reaction is catalyzed by Cu++and inhibited by small amounts of Ag+and Cl−. The results are interpreted in terms of a chain reaction mechanism involving UO2+and HO2as chain carrier

ISSN:0008-4042    

DOI:10.1139/v56-182

出版商:NRC Research Press    

年代:1956

数据来源: NRC

摘要:

The solubility of tin in aluminum, between 400° and 645 °C, has been determined by an isothermal method. The system Al–Pb–Sn has been investigated, isothermally, at 500° and 600 °C. The eutectic temperature and composition of this system have also been determined. The structure of the phases in completely solid alloys has been identified by photomicrography. The liquidus curves at 500° and 600 °C. are continuous, extending across the ternary diagram from the Al–Pb system to the Al–Sn system. On neither of the two isotherms does a two-liquid region occur, despite the fact that a well-defined two-liquid region exists at temperatures above 650 °C. This was found to be due to inaccuracy in the published diagram for the Al–Sn system and this led to the work mentioned above. The solubility of tin in aluminum is much less than it has been supposed and this causes the surface of solid aluminum to intrude into the solid diagram at an early stage, thus blocking out the two-liquid region. The ternary eutectic temperature is 183.0 °C. and the composition, 0.08 weight per cent Al, 38.1% Pb, and 61.7% Sn. In any alloy at room temperature, the solid phases are: primary aluminum, α-lead, and β-tin. Brinell Ball and Vickers Diamond Pyramid hardness tests show that the ternary eutectic alloy is the hardest of the system. When alloys approximating to the eutectic composition are used as solders, it has been found that the alloy of ternary eutectic composition has a greater shear strength than ordinary solder.

ISSN:0008-4042    

DOI:10.1139/v56-183

出版商:NRC Research Press    

年代:1956

数据来源: NRC

摘要:

A new synthesis of DL-glutamic acid was carried out in an over-all yield of 87% from condensation between β-propiolactone and the sodium salt of diethyl acetamidomalonate, followed by acid hydrolysis. When desired, the intermediate product, the diethyl ester of N-acetyl-2-carbethoxyglutamic acid, could be isolated in a 68% yield and hydrolyzed to glutamic acid via the hydrochloride in a 95% yield.

ISSN:0008-4042    

DOI:10.1139/v56-184

出版商:NRC Research Press    

年代:1956

数据来源: NRC