摘要:

AbstractAcyloxy derivatives of silicon were prepared by the interchange reaction between carboxylic acids (including various grades of palmitic acid) and tetraethoxysilane, and by the interchange reaction between palmitic acid and technical ethyl silicate (silica content 40%) or technical isopropyl silicate (silica content 38%). In most of the reactions, sodium methoxide was used as catalyst. Some physical properties of the reaction products were determined, and the materials made from palmitic acid were evaluated as water‐repellent coatings on cotton clot

ISSN:0021-8871    

DOI:10.1002/jctb.5010180401

出版商:John Wiley&Sons, Ltd    

年代:1968

数据来源: WILEY

摘要:

AbstractThe total pressure and the compositions of the vapour and liquid phases of the methanol–benzene system have been determined under equilibrium conditions at 100°, 120°, 140°, 160°, 180°, 200° and 220° for ten levels of concentration. The corresponding activity coefficients of methanol and benzene are reported; their values indicate that the equilibrium data are thermodynamically consistent.An azeotrope is found at all temperatures, its methanol content increasing as the temperature is increased. The relationship logPaz= 6·5098—(1,766/T) expresses the interdependence of the azeotrope vapour pressurePaz(lb/in2abs.) and temperatureT(°K).Estimates of integral heat of mixing (HE) and entropy change due to mixing (SE) as functions of liquid composition (xmeth) have been made from the excess free energy of mixingGE,(T)xmethfunctions. BothHEandSEat a givenxare positive increasing functions of temperature. These phenomena are discussed in terms of the dissociation of methanol ‘polymer’ and the formation of benzene–me

ISSN:0021-8871    

DOI:10.1002/jctb.5010180402

出版商:John Wiley&Sons, Ltd    

年代:1968

数据来源: WILEY

摘要:

AbstractA novel cyclic process producesp‐cresol from toluene; toluene with iodosotoluene (derived from iodo‐toluene) gives the intermediate ditolyliodonium salt converted by catalysed hydrolysis into cresol and iodotoluene (which is recycled as ‘catalyst’.) In the final product,o‐cresol content is low andm‐cresol is undetectable. The process reaches a steady state independent of theo‐/p‐isomer ratio of the iodotoluene ‘catalyst’. In a similar way,p‐chloronitrobenzene can be made by reaction of di‐(p‐chlorophenyl)iodonium salt (derived from chlorobenzene and chloro‐iodos

ISSN:0021-8871    

DOI:10.1002/jctb.5010180403

出版商:John Wiley&Sons, Ltd    

年代:1968

数据来源: WILEY

摘要:

AbstractCarbonatation of hydrated lime compacts produces shrinkage and changes in mechanical properties comparable with those found in similarly treated compacts of bottle‐hydrated cement and samples of hardened Portland cement paste. From experimental results obtained with the simpler lime system a mechanism for carbonatation shrinkage is proposed that postulates a through‐solution reaction and induced cycles of wetting and drying.Experiments on compacts of bottle‐hydrated cement show that carbonatation of the ‘combined lime’ is at least as rapid and extensive as the carbonatation of the ‘free lime,’ and that contrary to current opinion the former reaction results in even greater carbonatation shrinkage. The mechanism for carbonatation shrinkage of this system is considered to be connected with dehydration and polymerisation of the hydrous silica product of

ISSN:0021-8871    

DOI:10.1002/jctb.5010180404

出版商:John Wiley&Sons, Ltd    

年代:1968

数据来源: WILEY

摘要:

AbstractMolten ionic oxides possess important desirable properties: thermal stability, and useful chemical properties resulting from their acid or basic behaviour, i.e., from their capacity to accept or donate an oxygen ion, and, in several cases, relatively low melting points, well below 1000°c.Bismuth trioxide was found to effect a two‐temperature decomposition of ammonium chloride, yielding ammonia and hydrogen chloride. Molten antimony trioxide was found to attack rock phosphate and convert part of the phosphate to a water‐soluble form. Molten lead monoxide was found to dissolve calcium oxide readily, to dissolve chromic sesquioxide, to decompose chromite ore and to permit an extraction of iron‐free lead chromate into an upper layer of molten alkali chloride. Addition of lead sulphide to a lead monoxide melt caused formation of elemental lead and lead sulphate.Vanadium pentoxide was found to decompose ammonium chloride, yielding first, hydrogen chloride and then, ammonia. The reaction of a vanadium pentoxide melt with rock phosphate, studied in some detail, resulted in water‐solubilisation of the phosphate. The product formed in the melt is probably a calcium phosphate vanadate, from the aqueous solution of which calcium can be precipitated by ammonium carbonate; the ensuing ammonium phosphate and vanadate solution can be separated by known methods, permitting recovery of the vanadium pentoxide, and yielding ammonium p

ISSN:0021-8871    

DOI:10.1002/jctb.5010180405

出版商:John Wiley&Sons, Ltd    

年代:1968

数据来源: WILEY

摘要:

AbstractInfra‐red absorption spectra have been obtained by the KBr disc technique for some fifty commercial ion‐exchange resins with quaternary ammonium, tertiary and mixed amine, sulphonic, phosphonic, secondary phosphate, and carboxylic groups, as well as for a number of experimental resins, including some of the solvent‐modified type. The use of the technique in structural characterisation of ion‐exchange resins is di

ISSN:0021-8871    

DOI:10.1002/jctb.5010180406

出版商:John Wiley&Sons, Ltd    

年代:1968

数据来源: WILEY

ISSN:0021-8871    

DOI:10.1002/jctb.5010180407

出版商:John Wiley&Sons, Ltd    

年代:1968

数据来源: WILEY