摘要:

AbstractCommercial samples of pyridine derived from coal tar show a variability in the ease with which they are catalytically hydrogenated that can be correlated with the amount of sulphur‐containing impurities. The non‐basic contaminants were separated from two typical samples of pyridine by passing steam through acidified aqueous solutions. From the first, which was a refined sample, there was obtained a small amount ofo‐xylene: the second, a cruder technical grade, furnished an authenticated specimen of tetrahydrothiophen (thiophan), an individual which was thus recognized for the first time as a coal‐tar constituent. It is not difficult to reduce the sulphur content of a crude pyridine from about 0·022% by weight to less than 0·001% by the process described. Alternatively, if the sample is boiled with 1·5% by weight of potassium permanganate and redistilled, the sulphur content is reduced to abo

ISSN:0021-8871    

DOI:10.1002/jctb.5010020501

出版商:John Wiley&Sons, Ltd    

年代:1952

数据来源: WILEY

摘要:

AbstractA greatly improved method of preparation of 4:5‐diaminopyrimidine, which is an important starting material for pteridine and purine syntheses, is described in detail. The route from thiouracil involves eight stages, but purifications, except that of the final product, have been avoide

ISSN:0021-8871    

DOI:10.1002/jctb.5010020502

出版商:John Wiley&Sons, Ltd    

年代:1952

数据来源: WILEY

摘要:

AbstractThe reaction between tertiary alcohols and boric acid has been investigated and esterification has been shown to occur using an azeotropic‐distillation method. However, all reaction products decomposed on attempted purification. The rate of esterification of tertiary alcohols is much slower than that of primary or secondary alcohols. The separation of alcohols from mixtures using direct esterification with boric acid is thus applicable to tertiary as well as primary and secondary alcohols. The scope of this method of separation has been studied and it was shown that whereas enols interfere, esters and acids do not. Moreover, the separation must be conducted below about 110° if tertiary alcohols are prese

ISSN:0021-8871    

DOI:10.1002/jctb.5010020503

出版商:John Wiley&Sons, Ltd    

年代:1952

数据来源: WILEY

摘要:

AbstractTristrontium silicate, 3SrO,SiO2, was not discovered by previous investigators of the system SrO‐SiO2. The preparation of the new compound is described and optical properties andX‐ray spacings are given. A comparison is made between 3SrO,SiO2and 3CaO,SiO2, the principal cementing compound in Portland cement. It is shown that the strontium compound has not the property of hardening under water, but the possibility remains that hardening may take place in sulphate solutions, and that cements in which strontium is wholly or partly substituted for calcium may be of value in resisting attack by sea‐water or soil sulp

ISSN:0021-8871    

DOI:10.1002/jctb.5010020504

出版商:John Wiley&Sons, Ltd    

年代:1952

数据来源: WILEY

摘要:

AbstractThe azeotrope of pyridine and water has been determined at atmospheric pressure and under reduced pressures down to 120 mm. The azeotrope is relatively unaffected by pressure reduction, a change of 600 mm. altering the azeotrope composition by 10% from 59·5% at 758 mm. to 53·8% pyridine at 120 m

ISSN:0021-8871    

DOI:10.1002/jctb.5010020505

出版商:John Wiley&Sons, Ltd    

年代:1952

数据来源: WILEY

摘要:

AbstractA number of mono‐ and di‐chlorotitanium alkoxides have been prepared by the method of Jennings, Wardlaw&Way (1936). Thus acetyl chloride reacts with titanium tetra‐alkoxides to give monochlorotitanium trialkoxides:Ti(OR)4+ CH3·COCl = TiCl(OR)3+ CH3·CO2RThe monochloro‐esters, when treated with a further molecular proportion of the same reagent, yield dichlorotitanium dialkoxides:TiCl(OR)3+ CH3·COCl = TiCl2(OR)2+ CH3·CO2RThe dichloro‐compounds have also been obtained by the action of titanium tetrachloride on alcohols:TiCl4+ 2ROH = TiCl2(OR)2+ 2HClIn general these products are viscous liquids, soluble in organic solvents and very easily hydrol

ISSN:0021-8871    

DOI:10.1002/jctb.5010020506

出版商:John Wiley&Sons, Ltd    

年代:1952

数据来源: WILEY

摘要:

AbstractA calorimeter and technique for the differential thermal analysis of soap‐oil systems such as greases are described. Results are given for the temperatures and latent heats of the phase transformations which occur in grease systems made from lithium stearate, lithium 12‐hydroxystearate, or mixtures of these two soaps, and a hydrocarbon lubricating oil. Estimates of the solubilities of the soaps in the oil as functions of temperature have been made on the basis of the latent‐heat data.Lithium greases have been prepared, varying the temperature conditions during their preparation so that the soap fibres present in the final greases were grown while the system existed in different phase structures. The hardness and the resistance to oil separation are found to be determined by the soap phase existing during the growth of the fibres; this is attributed to the influence of the soap phase structure on the shape and size of the fibres pro

ISSN:0021-8871    

DOI:10.1002/jctb.5010020507

出版商:John Wiley&Sons, Ltd    

年代:1952

数据来源: WILEY

摘要:

AbstractMethods hitherto applied for the preparation of silicomolybdic and silicotungstic acids give non‐reproducible results. A procedure is recommended for their preparatio

ISSN:0021-8871    

DOI:10.1002/jctb.5010020508

出版商:John Wiley&Sons, Ltd    

年代:1952

数据来源: WILEY

摘要:

AbstractA partly cyclic process is described for the separation of the mixed hydroxides of the cerium‐group elements into cerous salts and into concentrates containing, respectively, lanthanum salts, mixed praseodymium‐neodymium‐samarium hydroxides or nitrates, and crude thorium phosphate.The mixed hydroxides of praseodymium, neodymium and samarium are fractionally precipitated with ammonium hydroxide, leaving lanthanum in solution. Portion of the praseodymium, neodymium and samarium concentrate is used to precipitate basic salts of ceric cerium and thorium, the remainder being recovered. Cerium is obtained from the mixture of basic salts by reducing ceric compounds to the cerous state and precipitating thorium as a basic salt. Lanthanum is finally precipitated as lanthanum oxalate or lanthanum carbonate and cerium as sodium cerium sulphate.Electrometric titrations of lanthanon solutions have been made at 80° to obtain data facilitating control of the various separ

ISSN:0021-8871    

DOI:10.1002/jctb.5010020509

出版商:John Wiley&Sons, Ltd    

年代:1952

数据来源: WILEY

摘要:

AbstractThe comparative effects of potassium dichromate, sodium nitrite, sodium benzoate and soluble oil as corrosion‐inhibitors have been partially examined. The corrosion medium used is either sodium chloride solution or diluted sea‐water.Although steel is readily protected in the presence of chlorides, cast iron gives results that are somewhat anomalous. The addition of soluble oil to a system already undergoing corrosion suppresses the attack. The importance of maintaining adequate concentrations of the inhibitor is discus

ISSN:0021-8871    

DOI:10.1002/jctb.5010020510

出版商:John Wiley&Sons, Ltd    

年代:1952

数据来源: WILEY