摘要:

AbstractOf seven common aldehydes examined on cyanide‐treated Dowex‐2 columns, vanillin, salicylaldehyde, benzaldehyde and crotonaldehyde were more or less completely adsorbed and were eluted with water to only very small extents; furfural was completely recoverable and formaldehyde and acetaldehyde partially so. There was some indication of polymerization of some of the aldehydes on the column.Acetone and ethyl methyl ketone were very easily eluted with water from these colu

ISSN:0021-8871    

DOI:10.1002/jctb.5010071002

出版商:John Wiley&Sons, Ltd    

年代:1957

数据来源: WILEY

摘要:

AbstractExperimentalT‐x‐ydata of the system: acetone‐ethyl methyl ketone‐cyclohexane at 760 mm. Hg pressure are reported. The data were obtained using a modified Colburn type of equilibrium still. No ternary azeotrope was observed.The experimental data were found to be thermodynamically consistent according to the method of Krishnamurty&Venkata Rao which is based on the Gibbs‐Duhem equation.The activity coefficient data of the present system have been satisfactorily correlated with the modified Margules equations developed earlier, using a ternary constant Ct= 0·5. In the case of the present system, the modified Margules equations with Ct= 0·5 are equivalent to the three‐suffix ternary Margules equations of Wohl, with C = 0·305. The ternary smoothed experimentalT‐x‐ydata are compared with the data calculated using the modified Margules equations with Ct= 0·5 and there is close agreement between the calculated and experimental data.It is suggested that the thermodynamic consistency test proposed by Krishnamurty&Venkata Rao and the modified Margules equations may be used together for mathematical analysis of the ternary vapour‐liquid equilibrium data since the same smoothed experimental log γi/γj values can be us

ISSN:0021-8871    

DOI:10.1002/jctb.5010071003

出版商:John Wiley&Sons, Ltd    

年代:1957

数据来源: WILEY

摘要:

AbstractSeveral modifications of the ‘hexagonal’ tetracalcium and dicalcium aluminate hydrates have been obtained, some of which have not been described previously. Only a newly established 4CaO,Al2O3, 19H2O hydrate, and an α‐form and a hitherto undescribed β‐form of a 2CaO,Al2O3,8H2O hydrate have been found to occur in the aqueous system at 25°. Other modifications are produced on drying under various conditions. The 4CaO,Al2O3,19H2O hydrate, characterized in the X‐ray patterns by a longest basal spacing of 10·6Å, is dehydrated relatively easily to give a mixture of α‐and β‐forms of a 13H2O hydrate, characterized by longest basal spacings of 8·2Å and 7·9Å, respectively. There is little difference in stability between the two forms and it appears to be a matter of chance as to the relative amount of each which may be formed. Two other tetracalcium aluminate hydrates have been obtained with water contents of 11H2O and 7H2O, both of which give longest basal spacings of 7·4Å. The α‐ and β‐forms of 2CaO,Al2O3,8H2are characterized by longest basal spacings of 10·7Å and 10·4Å respectively. The α‐form appears to be more stable than the β‐form. Three other states of hydration of the dicalcium compound exist, having water contents of 7·5H2O, 5H2O and 4H2O, and giving longest basal spacings of 10·6Å, 8·7Å, and 7·4Å, respectively. With various preparations of the compound 3CaO,Al2O3,CaSO4,aq., basal spacings of 10·3Å, 9·6Å, 8·9Å, 8·2Å, and 8·0Å have

ISSN:0021-8871    

DOI:10.1002/jctb.5010071004

出版商:John Wiley&Sons, Ltd    

年代:1957

数据来源: WILEY

摘要:

AbstractThe reaction constant, and its temperature‐dependence, of the reaction naphthalene + picric acid ⇌ naphthalene picrate has been determined and shown to account for the losses of naphthalene in tests in which air containing naphthalene in known concentrations was bubbled through picric acid. This enables a correction to be applied when carrying out the determination a t 10–18°, the wash‐bottles being immersed in a thermostatically controlled bath. Dissociation of the recovered picrates, when washing after filtering, can be minimized by the use of 0·02Npicric acid solution as the washi

ISSN:0021-8871    

DOI:10.1002/jctb.5010071005

出版商:John Wiley&Sons, Ltd    

年代:1957

数据来源: WILEY

摘要:

AbstractThe conventional method of determining the picrates formed by the unsaturated hydrocarbons such as indene is the use of an aliquot of the solution of the recovered picrates in chloroform, another aliquot being used for the determination of the total picrates. The accuracy of these determinations is enhanced by the use, for each, of the total quantity of recovered picrates: this is facilitated by the use of acetone as the solvent and bromothymol blue as the indicator in the titration of the total picrates. Errors in the determination of the indene are minimized by using suitable excesses of acetic acid and Wij's solution and keeping for 20 min. before titrating the unused iodine with standard sodium thiosulphate solution.

ISSN:0021-8871    

DOI:10.1002/jctb.5010071006

出版商:John Wiley&Sons, Ltd    

年代:1957

数据来源: WILEY

摘要:

AbstractThe performance of a naphthalene washer is dependent on the ambient temperature and thus can vary considerably between day and night and between successive days. It follows that the duration of a naphthalene test should be 24 h. No difficulty arises in collecting ‘sufficient naphthalene’ in this period, even for gas of the lowest naphthalene concentration at present specified, if the rate of gas flow is increased to 12 cu. ft./h. and an efficient absorption system is employed. In the recommended method, the wash‐bottles are immersed in a thermostatically controlled bath and a correction applied for the loss of naphthalene due to dissociation of naphthalene picrate. For the filtration of the recovered picrates, a No. 3 porosity sintered‐glass disc is recommended. The error in the recommended method due to saturated hydrocarbons which do not cause blockage of fine gas services (such as 1‐methylnaphthalene) is likely to be small, as the test is carried out at a temperature above the conven

ISSN:0021-8871    

DOI:10.1002/jctb.5010071007

出版商:John Wiley&Sons, Ltd    

年代:1957

数据来源: WILEY

摘要:

AbstractThe infra‐red absorption spectra of a number of 2‐monosubstituted and 2: 5‐disubstituted furan derivatives have been measured over the frequency range 2000–700 cm.−1. Two bands at approximately 1225 cm.−1and 1020 cm.−1are characteristic of the furan ring and other tentative assignments are made in the 1000cm.−1to 700 cm.−1region for the identification of the type of substitution. A nitro‐group in the α‐position of a furan ring absorbs strongly at 1535–1505

ISSN:0021-8871    

DOI:10.1002/jctb.5010071008

出版商:John Wiley&Sons, Ltd    

年代:1957

数据来源: WILEY

摘要:

AbstractThe strength of concrete is greatly influenced by the water/cement ratio used in mixing the concrete before placing. In the examination of samples of hardened concrete, a knowledge of the original water/cement ratio is, therefore, most desirable. This cannot be found only by chemical analysis because normally much of the original water has evaporated leaving voids within the concrete as a continuous capillary porosity.

ISSN:0021-8871    

DOI:10.1002/jctb.5010071009

出版商:John Wiley&Sons, Ltd    

年代:1957

数据来源: WILEY

ISSN:0021-8871    

DOI:10.1002/jctb.5010071001

出版商:John Wiley&Sons, Ltd    

年代:1957

数据来源: WILEY