摘要:

AbstractDehydration of 1,1‐diphenyl‐2‐ethyl‐2‐methylbutan‐1‐01 gives a hydrocarbon C19H22which was identified as 3‐ethyl‐4,4‐diphenylpent‐2‐ene.Oxidation of C19H22with chromium trioxide in acetic anhydride gave acetophenone, benzophenone and α,α‐diphenylpropionic acid. Oxidation with chromium trioxide in aqueous sulphuric acid gave 2,2‐diphenylpentan‐3‐one, benzophenone and benzoic acid.A tentative explanation for the production of a

ISSN:0375-9210    

DOI:10.1002/jctb.5020211001

出版商:John Wiley&Sons, Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractSpecific surface areas and pore size distribution analysis were taken as essential parameters to explore the microstructure of hardened gypsum pastes. The hydration of gypsum plaster is essentially affected by the water/plaster ratio of the mix, and by the presence of additives which might act as retarders or accelerators to the hydration process. Affecting the microstructure would mutually lead to variations of the compressive strength of the hardened pastes, and these variations are also discussed.Results are mainly expressed in terms of the solid (measured by the extent of its specific area) to the space (pore) ratios. Dual distribution of pore sizes was observed and the two groups of pores are designed as S (small) and L (large) pores. Similarities to the microstructure of hardened Portland cement pastes are indicated. Accelerators appear to function differently from retarders, and the effects of water/plaster ratios were investigated in both cases. The results obtained may carry many significant practical implications to the future use of hardened gypsum pastes.

ISSN:0375-9210    

DOI:10.1002/jctb.5020211002

出版商:John Wiley&Sons, Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractThe effects of some additives on the autoclave dehydration of gypsum have been determined. It was possible to accelerate the reaction by the addition of calcium sulphate hemihydrate or orthorhombic calcium sulphate to the gypsum. Plasters prepared by the sodium succinate method in the presence of the latter additive had a high water requirement and poor mechanical properties.

ISSN:0375-9210    

DOI:10.1002/jctb.5020211003

出版商:John Wiley&Sons, Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractThe double carbonates of strontium and barium SrxBa2‐x(CO3)2have been shown to undergo, on heating, a transition from an orthorhombic to a hexagonal crystal form. The temperature at which this phase change occurs, and the heat required for the transition, are dependent on the value of

ISSN:0375-9210    

DOI:10.1002/jctb.5020211004

出版商:John Wiley&Sons, Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractA comparative survey has been made of alkaline, fluorine‐containing, and charcoal‐based materials as potential catalysts for the vapour phase dealkylation of alkylphenols. o‐Cresol was used as the feed in an initial screening, and those catalysts showing most activity were then subjected to a more detailed study using higher‐boiling feedstocks. The most interesting results were obtained using aluminium borofluoride or zinc fluoride, each on a γ‐alumina support. In addition to extensive dealkylation, these catalysts also gave rise to isomerising effects. Their activity, however, rapidly declined because of carbon deposition, but could be fully restored by heating in an oxygen/nitrogen stream. The use of metal‐impregnated charcoals gave more selective dealkylation than active charcoal alone, but the improvement did not warrant the additional cost; moreover these materials could not be revivified by conventional means. The alkaline catalysts displayed a lower level of activity and could not be completely regenerated after deactivation because of carbonation in addition to carbo

ISSN:0375-9210    

DOI:10.1002/jctb.5020211005

出版商:John Wiley&Sons, Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractIsothermal vapour‐liquid equilibrium data were determined in a modified Dvorak and Boublik still for the binary system n‐pentane‐benzene at 35°, 40°, 45° and 50°c. Liquid activity coefficients, γ, were evaluated and correlated. Experimental equilibrium values were extrapolated to the isobaric condition of atmospheric pressure. The extrapolated data agree well with that reporte

ISSN:0375-9210    

DOI:10.1002/jctb.5020211006

出版商:John Wiley&Sons, Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractA computer programme, RWCRVE, is reported that plots both the formation and enthalpic curves from ΔH° and ΔS° of complexing. RWCRVE (i) permits a detailed analysis of the factors dictating the shapes of enthalpic curves, and (ii) suggests new conclusions that may be drawn from experimental enthalpic curves; such conclusions concern symbiosis effects of a complexed ligand upon the next ligand‐metal bond being formed, ion‐pair effects and extrapolations of these discussions to industrial and biological systems where all the details of complexing may not be clearly esta

ISSN:0375-9210    

DOI:10.1002/jctb.5020211007

出版商:John Wiley&Sons, Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractA reversed two‐environment model of micromixing in a flow reactor in which the feed enters a maximum mixedness environment and then passes to a segregated environment is presented. The performance equations for an arbitrary residence time distribution are developed and employed to analyse the behaviour of growth processes in a continuous stirred tank reactor under intermediate states of micromixing. The results, which are bounded by the two extremes of micromixing, indicate that micromixing is important in growth processes and that segregation appears to reduce the rate of cell productio

ISSN:0375-9210    

DOI:10.1002/jctb.5020211008

出版商:John Wiley&Sons, Ltd    

年代:1971

数据来源: WILEY