摘要:

AbstractAfter a discussion of the requirements to be met by the method of stirring used in liquid calorimeters for accurate heat measurements, a description is given of a calorimeter constructed on a new principle. The development of heat occurs in a cylinder which is somewhat smaller than the calorimeter vessel. Water is circulated between the two walls, where the thermometer is placed by means of a centrally fixed centrifugal pump. In this way, the actual wall temperature of the calorimeter‐vessel is measured; this is essential for the accurate calculation of the “radiation” correction. A simple method is described for determining the heat due to stirring. Finally, the required minimum duration of the main period is disc

ISSN:0165-0513    

DOI:10.1002/recl.19470660302

出版商:WILEY‐VCH Verlag    

年代:1947

数据来源: WILEY

摘要:

AbstractFor measuring a rise in temperature the ordinary Beckmann thermometer is in no way inferior to the resistance thermometer if the measurements are carried out in a definite way and if at the same time a number of precautions (with regard to vibrator, manostat and water jacket around the scale) are taken, in order to obviate the effects of possible errors in the instrument. In an example it is shown that by taking these things into consideration it is possible to obtain a (relative) temperature reading, which is accurate to 5 × 10−5°. Thus it is possible, by using the Beckmann thermometer, to carry out heat measurements reproducible to 0.

ISSN:0165-0513    

DOI:10.1002/recl.19470660303

出版商:WILEY‐VCH Verlag    

年代:1947

数据来源: WILEY

摘要:

AbstractA method is described for filling thin‐walled ampullae with volatile liquids with the total exclusion of air and water. In this way it is possible to weigh out accurately the amount of material used for a heat of combustion measurement before the experiment is made. To aid the combustion reaction in proceeding to completion a high platinum crucible is used covered with a platinum shield. In a normal heat of combustion reaction it is impossible to detect the presence of carbon monoxide in the combustion gases. The reproducibility obtained is 0.01‐0.

ISSN:0165-0513    

DOI:10.1002/recl.19470660304

出版商:WILEY‐VCH Verlag    

年代:1947

数据来源: WILEY

摘要:

AbstractIn order to be able to calculate readily the so‐called “radiation” correction in calorimetric measurements, the jacket‐temperature must be kept constant and the contents of the calorimeter vessel must be stirred at a constant speed. This article describes a thermo‐regulator for this purpose, in which the fluctuations are not greater than 0.002°.For every calorimeter used for accurate work, it is desirable to investigate beforehand whether the heat exchange between the vessel and the jacket satisfiesNewton'sequation. With the help of recent data it has been investigated how wide the air layer may be before convection occurs. This is necessary in order to obtain a system which satisfiesNewton'sequation.Finally, various methods of approximation for calculating the “radiation” integral

ISSN:0165-0513    

DOI:10.1002/recl.19470660305

出版商:WILEY‐VCH Verlag    

年代:1947

数据来源: WILEY

摘要:

AbstractA review is given of the literature on the occurrence and application of Mundulea suberosa. Chemical investigation of the bark of the branches led to the isolation of rotenone, a white substance C23H20O7, m.p. 193‐195° C, and from the root bark a yellow substance C23H20O7, m.p. 216‐220° C was isolated. Both products contained two methoxyl groups. Treatment of the colourless crystals with glacial acetic acid and sulphuric acid furnished a yellow product of the composition C23H18O6. Oxidation with chromic acid gave a substance C23H18O7, m.p. 262°C. A comparison was made with known rotenoid substance of similar compo

ISSN:0165-0513    

DOI:10.1002/recl.19470660306

出版商:WILEY‐VCH Verlag    

年代:1947

数据来源: WILEY

摘要:

AbstractSolutions of radioactively tagged Cu‐acetate, Cu‐glycinate and “Ebesal” were injected intravenously in calves. After about 3 1/2 h the animals were killed, their livers destructed and metallic copper isolated from the destruction liquid by precipitation with A1.Measurement of the radioactivity showed increasing absorption with increasing strength of binding of the copper in the salts injected (acetate → glycinate → Ebesal). The suggestion is made that the liver might be able to destroy the Cu complex much better than other organs and so might collect the copper without serious competition by o

ISSN:0165-0513    

DOI:10.1002/recl.19470660307

出版商:WILEY‐VCH Verlag    

年代:1947

数据来源: WILEY

摘要:

Abstract4‐Carbethoxypyridine can be prepared in a simple way by treating pyridine with zinc and ethyl chloroformate, and subsequent thermal decomposition of the tetrahydrodipyridyl derivative (I) formed. The dihydropyridine derivative (II) then formed can be easily converted into the desired 4‐carbethoxypyridine (III) by heating with sulp

ISSN:0165-0513    

DOI:10.1002/recl.19470660308

出版商:WILEY‐VCH Verlag    

年代:1947

数据来源: WILEY

摘要:

AbstractThe ground bark ofDiospyrosmaritima gave on extraction with ether a mixture of several substances, three of which were isolated in a crystalline and pure form. The first substance had a melting point of 216°C, was colourless, insoluble in alkali and had the composition C20H32O. Acetylation led to the isolation of a product with a melting point of 232°C; an acetyl determination did not give satisfactory results. The second substance isolated from the extract turned out to be identical with scopoletin, 7‐hydroxy‐6‐methoxy‐coumarin. Several derivatives have been prepared. The third substance proved to be identical with plumbagin, 5‐hydroxy‐2‐methyl‐1,4‐napthoquinone, the active principle of Plumbago species. A review of several uses of Plumbago roots in India, Malayan States and Java is given. The relation to vit

ISSN:0165-0513    

DOI:10.1002/recl.19470660309

出版商:WILEY‐VCH Verlag    

年代:1947

数据来源: WILEY

ISSN:0165-0513    

DOI:10.1002/recl.19470660301

出版商:WILEY‐VCH Verlag    

年代:1947

数据来源: WILEY