摘要:

AbstractThe synthesis of 2‐mercapto‐4‐aminobenzoic acid, a compound which is the sulphur analogue of p‐amino‐salicylic acid (2‐hydroxy‐4‐aminobenzoic acid

ISSN:0165-0513    

DOI:10.1002/recl.19510700402

出版商:WILEY‐VCH Verlag    

年代:1951

数据来源: WILEY

摘要:

AbstractThe preparation of ethyl‐β‐chlorovinyl ether from the readily available dichloroacetal is reported. Careful fractionation of the product yields the pure cis‐ and trans‐isomers of which only the cis‐isomer gives a high yield (76%) of ethoxy‐acetylene on heating with potassium hydroxide.The corresponding ethyl‐β‐bromovinyl ether has likewise been separated into cis

ISSN:0165-0513    

DOI:10.1002/recl.19510700403

出版商:WILEY‐VCH Verlag    

年代:1951

数据来源: WILEY

摘要:

AbstractThe procedure finally adopted is the following.Entrainer: Pure isooctane (2.2.4‐trimethylpentane), bpt. 99° C.Apparatus: Still of 8 cm diameter, capacity about 150 ml; heating by means of an oil bath kept at about 165° C.Receiver of theBidwell‐Sterling‐type; capacity of calibrated part 2 ml, cross section about 0.1 cm2.Joints of one brand of glass, ground in.Special features: Cleaning by hot chromic acid mixture; apparatus kept in this medium until use.Bumping is prevented by the use of about 1 g of washed and dried pumice stones of øav=2 mm.Creeping is prevented by the use of two glass wool mats, situated in the vertical tube, connecting still and receiver.Water vapour diffusing from and to the apparatus is caught in a set of moisture control tubes (figures 1 and 3).The main water column and droplets possibly sticking to the glass walls are transported to the calibrated part of the receiver with the help of a defatted copper wire.Accuracy: Calibration on BaCl2. 2 H2O yielded a standard‐deviation s = 0.010 g, corresponding to a coefficient of variation C = 102s/x¯ = 0.55.The average discrepancy between calculated and measured values was 30 mg.“Constant” readings were reliable within less than 10 mg.Timerequired for reaching constant

ISSN:0165-0513    

DOI:10.1002/recl.19510700404

出版商:WILEY‐VCH Verlag    

年代:1951

数据来源: WILEY

摘要:

AbstractIn the hydrolysis of 5,5‐dimethyl‐oxazolidinediones‐2,4 and 5‐phenyl‐oxazolidinediones‐2,4, with alkali, a carbamylo‐α‐hydroxy‐acid and an α‐hydroxy‐amide are produced in a constant ratio, independent of the nature of the N‐substituent, the decomposition temperature and the concentration of the alkali.For 5,5‐dimethyl‐oxazolidinediones‐2,4 this ratio is 1.66 on the average and for 5‐phenyl‐oxazolidinediones‐2,4 5.2 on the average.Practically the same ratios are found in the hydrolysis of the cor

ISSN:0165-0513    

DOI:10.1002/recl.19510700405

出版商:WILEY‐VCH Verlag    

年代:1951

数据来源: WILEY

摘要:

AbstractI. The osmotic permeability of a cupric ferrocyanide membrane deposited on porous pyrex was determined at 22° and 33° C for glucose solutions up to 25%, with errors below 2%.It was found that the so‐called “seasoning” of the cell took place at 33° in two jumps at an osmotic pressure of 33 atm. After seasoning the cell is considerably more permeable to water and the velocity vs. concentration curve displays greater steepness and less curvature.II. Experiments were carried out with the system glucose solution ‐ semipermeable membrane ‐ aminopyrine solution, and an increase of concentration of 11.7% resp. 23.0% in the latter

ISSN:0165-0513    

DOI:10.1002/recl.19510700406

出版商:WILEY‐VCH Verlag    

年代:1951

数据来源: WILEY

摘要:

AbstractBy an alteration of the zirconium‐alizarin ratio in the reagent the sensitivity ofSanchis'method is so increased that the latter becomes suitable for a determination with the aid of a photoelectric colorimete

ISSN:0165-0513    

DOI:10.1002/recl.19510700407

出版商:WILEY‐VCH Verlag    

年代:1951

数据来源: WILEY

摘要:

AbstractThe isooctane entrainment distillation technique, developed in a previous paperD. A. A. Mossel and J. F. Reith, Rec. trav. chim. 70, 297‐312 (1951).was applied to a set of model substrata, i.e. crystal hydrates, a choice of biocolloids and substrates rich in lipids and essential oils.The data for hydrates and biocolloids obtained in the new technique were in satisfactory agreement with those arrived at using the best indirect reference methodJ. H. van de Kamer and N. F. Jensen, Anal. Chim. Acta 3, 397‐404 (1949)..The entrainment distillation technique operated more quickly than this reference method and had a more general applicability, since substrates rich in lipids and essential oils did not offer any difficulties.Slow dehydration of lactose hydrate and the necessity for neutralizing acid systems containing levulose or sucrose before desiccation are still disadvantages of the met

ISSN:0165-0513    

DOI:10.1002/recl.19510700408

出版商:WILEY‐VCH Verlag    

年代:1951

数据来源: WILEY

摘要:

AbstractApplication ofOnsager'ssymmetry relations to the process of diffusion of a solution through a membrane shows that measured osmotic pressures deviate from those calculated thermodynamically in proportion to the permeability of the membrane to the solute molecules. Therefore little is learned from one dynamic osmotic measurement but by simultaneous measurements of osmotic pressure and permeation at different membranes the entire molecular weight distribution of the solute can be computed.

ISSN:0165-0513    

DOI:10.1002/recl.19510700409

出版商:WILEY‐VCH Verlag    

年代:1951

数据来源: WILEY

摘要:

AbstractWhen 3‐bromo‐2,4‐dihydroxypyridine is chlorinated in aqueous hydrochloric acid solution by adding hydrogen peroxide solution, 5‐bromo‐3‐chloro‐2,4‐dihydroxypyridine is formed. Hence the chlorine atom enters the 3‐position, the bromine atom being removed from this position and reintroduced at the 5‐position.5‐Bromo‐3‐chloro‐2,4‐dihydroxypyridine was also prepared by brominating 3‐chloro‐2,4‐dihydroxypyridine and chlorinating 5‐bromo‐2,4‐dihydroxypyridine. Its structure was established in different ways,i. e.by converting it into 3‐chloro‐2,4‐dihydroxypyridine on partial reduction, by converting it into 4‐amino‐2,3‐dichloro‐5‐bromopyridine and into 4‐amino‐2,5‐dibromo‐3‐chloropyridine. The st

ISSN:0165-0513    

DOI:10.1002/recl.19510700410

出版商:WILEY‐VCH Verlag    

年代:1951

数据来源: WILEY

摘要:

AbstractThe reaction between liquid hydrocarbons and hydrogen atoms prepared according to Wood's method is caused by hydrogen atoms only.

ISSN:0165-0513    

DOI:10.1002/recl.19510700411

出版商:WILEY‐VCH Verlag    

年代:1951

数据来源: WILEY