摘要:

Photoacoustic spectroscopy (PAS) has been used to monitor the surface acidity of solid (alumina-silica) catalyst, since PAS has the inherent advantage of measuring absorption bands of solid surfaces conveniently. Three kinds of acidic sites have been detected and their relative abundance estimated.

ISSN:0038-7010    

DOI:10.1080/00387018008064025

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

The H NMR parameters of digitoxose and canarose, two 2,6-dideoxyhexopyranose sugars obtained from hydrolysis of cardio active glycosides, have been measured. The accurate coupling constants obtained through the use of resolution enhancement methods have been used to confirm the ring conformations.

ISSN:0038-7010    

DOI:10.1080/00387018008064026

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

Positive and negative ion mass spectra of organic polymers were recorded using the Laser Microprobe Mass Analysis (LAMMA) technique. The mass spectra are characteristic of both the hydrocarbon backbone of simple straight-chain polymers [polyethylene, poly(vinyl chloride), and poly(tetrafluoroethylene)] and of slight changes in side chain functionality [poly (phenyl methacrylate) and poly (benzyl methacrylate)]. The spectra show ion clusters having masses up to and beyond the monomer unit. This study indicates the power of the LAMMA technique for organic polymer materials analysis. Preliminary analysis of the mass patterns is given for the most probable positive and negative molecular cluster ions formed.

ISSN:0038-7010    

DOI:10.1080/00387018008064027

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

An accurate, simple and precise PMR procedure has been developed for the quantitation of benzyl benzoate (I) and benzyl cinnamate (II) as pure drugs and in Peru and Tolu balsams. The average recovery of pure I and II in standard mixtures using ethyl benzoate (III) as the internal standard was 100.2± 0.38% w/w and 100.0± 0.34 34% w/w respectively. The results of the assay using standard synthetic mixtures containing both I and II proved to be reproducible and gave a mean of 100.0 ± 0.54 w/w for I and 100.0 ± 0.62 w/w for II. Applying the same method for the determination of I and II in balsams, an average vlaue of 44.7% w/w was obtained for I and 4.4% w/w for II in Peru balsam. The corresponding average values for Tolu balsam were 11.6 w/w and 14.3% w/w. Moreover the method provides means for the ratio determination of I and II and the identification of the balsams.

ISSN:0038-7010    

DOI:10.1080/00387018008064028

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

The Raman, infrared and proton NMR spectra of the liquid molecules, C2H5-X(X˭Cl, Br, I) have been recorded. And the molecular structures have been studied on the basis of these spectra. Consequently a non-rigid structure in which a CH2group rotates freely with respect to the three hydrogen atoms of CH3group is established.

ISSN:0038-7010    

DOI:10.1080/00387018008064029

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

The He(I) photoelectronspectra of methyl allenyl ether and its sulphur analogue furnish information on lone pair (n)/π conjugation. Evidence is presented that methyl allenyl ether in the gasfase exists in two conformations being for a major part the stable s-cis and to a minor degree the s-trans rotamer. Empirical calculations (MIEHM) substantiate our proposals, whilst a semi-empirical method (MINDO/3) is not in disagreement with it. Our result is in contradiction with previous electron diffraction work.

ISSN:0038-7010    

DOI:10.1080/00387018008064030

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

The infrared and laser-Raman spectra of crystalline Ba5(ReO5)3Br are reported and an assignment for the internal vibrations of the square pyramidal ReO3−5anion is proposed. Force constants, bond orders and mean amplitudes of vibration are calculated. Some comparisons with other rhenium compounds are made.

ISSN:0038-7010    

DOI:10.1080/00387018008064031

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

A simple photon counting system for measuring very low optical spectral lines is described. It is of interest the cooling housing for its low cost and easy implementation. A comperison between the standard d. c. registration system and the photon counting one is given.

ISSN:0038-7010    

DOI:10.1080/00387018008064032

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

The infrared spectrum ofbis(acetylacetonato)zinc(II) monohydrate and its 18O-, 68Zn- and64Zn-labelled analogues have been determined. Band assignments have been made on the basis of the isotopically-induced shifts in relation to theC4vlocalized point symmetry of the molecule. Unliketris(acetylacetonato)chromium(III), there is no disagreement between the results of the12Oand metal isotope labelling techniques.

ISSN:0038-7010    

DOI:10.1080/00387018008064033

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

The infrared spectra of the isomeric complexes [Co(DH)2(py)(NCS)] and [Co(DH)2(py)(SCN)] (DH ˭ dimethylglyoximate anion, py ˭ pyridine) and their py-15N-, py-d5- and15NCS-labelled derivatives have been determined. Band assignments are based on the shifts incurred by labelling and on previous labelling studies applied to the complexes [Co(DH)2(py)X] (X ˭ CH3, Cl, Br, I).vCo-N(py) occurs at 464 cm−1in both complexes with an additional band at 450 cm−1in the isothiocyanate complex, whilevCo-N(DH) appears at 513 cm−1in both complexes.vCo-NCS occurs at 377 cm−1in the isothiocyanate complex whilevCo-SCN appears at 356 cm−1in the thiocyanate complex.

ISSN:0038-7010    

DOI:10.1080/00387018008064034

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor