摘要:

This paper describes a new catalytic process for linear alpha-olefins by oligomerization of ethylene using a soluble alkyl aluminum chloride-titanium tetrachloride catalyst. Important catalytic and polymerization variables, such as catalyst activity, selectivity to linear products, and molecular weight, are discussed. An ionic mechanism is proposed to explain the unusual features of this new process.

ISSN:0022-233X    

DOI:10.1080/00222337008060980

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

Polymerization of tetrafluoroethylene was carried out in bulk at low temperatures by initiation with γ-rays from a60Co source. It was found that a remarkable postpolymerization takes place even in the liquid phase. Kinetical analysis has been made of the in-source and postpolymerizations. An activation energy of 2.7 kcal/mole was obtained for the in-source polymerization and 10.3 kcal/mole for the postpolymerization. The long lifetime of polymer radicals in the liquid phase at -78°C seems to be due to the slow recombination rate of the polymer radicals, based on the rodlike shape of the polymer radicals.

ISSN:0022-233X    

DOI:10.1080/00222337008060981

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

Radiation-induced copolymerizations of various monomers, including perfluoro-olefines with CF2O and of α-olefines with monochlorotrifluoro-ethylene, have been studied. It was found that CF2O can be copolymerized randomly via radical process, with most of monomers examined and that alternating copolymers can be obtained from the copolymerization of a-olefines with monochlorotrifluoroethylene. The structural study of these copolymers was carried out by infrared, X-ray diffraction and NMR measurements. The structure of isobutylene-monochlorotrifluoroethylene copolymer was determined precisely through proton and fluorine resonances.

ISSN:0022-233X    

DOI:10.1080/00222337008060982

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

Polymerization of tetrafluoroethylene in monochlorodifluoromethane was carried out at low temperatures with -prays from a60Co source. An activation energy of 4.3 kcal/mole was obtained for the in-source polymerization, and this is higher than that of bulk polymerization, 2.7 kcal/mole. It was found that a remarkable postpolymerization takes place even if the reaction system is in liquid state. A kinetic treatment for the postpolymerization is described.

ISSN:0022-233X    

DOI:10.1080/00222337008060983

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

The specific velocity constants of free ion-molecule reactions and ion pair-molecule reactions are discussed. Assuming an equilibrium between solvated and desolvated reactive centers, the specific velocity constant of ion pair with a given charge-charge distance is expressed by

ISSN:0022-233X    

DOI:10.1080/00222337008060984

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

The distribution of the intercharge distance of ion pairs was derived from a solvated ion pair model. The calculation was applied to a fluorenylsodium-tetrahydrofuran system, and the equilibrium constants for the equilibria, contact ion pairs solvent separated ion pairs free ions, were calculated. Furthermore, the enthalpy and entropy changes for the equilibria were derived. Agreement with experimental data was satisfactory.

ISSN:0022-233X    

DOI:10.1080/00222337008060985

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

Kinetic studies are reported on the polymerization of tetrahy drofuran by trialkyloxonium salts. Triethyloxonium tetrafluoroborate (Et3OBF4) and -tetrachloroaluminate (Et3OAlC14) were employed as the initiator. At various times the polymerization system was treated with excess sodium phenoxide. The propagating species of polymer and the remaining triethyloxonium of initiator were converted quantitatively into the corresponding phenyl ethers. Phenetole from the remaining catalyst was successfully separated from the polymer phenyl ether by vacuum distillation. The concentrations of propagating species and the remaining initiator were determined separately by UV analysis of the corresponding phenyl ethers. In the polymerization by Et3OBF4a slow termination occurs to destroy the propagating species, i.e., this polymerization is not strictly a living system. The polymerization by Et3OAlC14, on the other hand, is characterized by a very rapid termination. On the basis of the time-[P*] and time-conversion data in the polymerization by Et30BF4, the propagation rate constant kpwas calculated kpaccording to

ISSN:0022-233X    

DOI:10.1080/00222337008060986

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

Reactivity of n-butyllithium-(CH3)2NCH2CH2OLi system in toluene (System N) and in cyclohexane as catalyst for copolymerization of styrene with 1,3-butadiene was studied. Copolymers obtained with System N ([OLi] /[CLi] = 1.5) were found to contain more styrene units than the feed monomer ratio, which also occurred with the catalyst system n-butyllithium-CH3OCH2CH2OLi (System A). Pale yellow crystalline precipitates were formed in System N. The precipitates were found to have such compositions as C6H5CH2Li·2(CH3)2NCH2CH2OLi and caused an enormous increase in the reactivity of styrene in the copolymerization reactions.

ISSN:0022-233X    

DOI:10.1080/00222337008060987

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

The model chelating compounds β-[2,4-bis(dimethylamino)-s-triazin-6-yl] hydrazinoacetic acid, β-[2,4-bis(dimethylaniino)-s-triazind-yl] hydrazino-N, N-diacetic acid, 2,4-bis(dimethylamino)-s-triazin-6-yl-aminoacetic acid, and 2,4-bis(dimethylamino)-s-triazin-6-yl-iminodiacetic acid have been synthesized and characterized by composition analysis, infrared spectroscopy, and potentiometric titration data. The copper(II), nickel(II), cobalt(II), zinc(II), magnesium(II), and palladium(II) complexes of the first two model compounds, and the copper, nickel, cobalt, and zinc complexes of the third and fourth model compounds have been prepared. The infrared absorption spectra of the model compounds and their complexes were recorded for the range 3800 to 600 cm−1, and the assignment of pertinent bands was made by comparison with reported infrared correlations. In those cases where applicable, shifts in the NH stretching vibration and carboxylate stretching vibration frequencies of the metal complexes were compared to those of the proper references and used as an indication of possible chelation effects in the metal complexes.

ISSN:0022-233X    

DOI:10.1080/00222337008060988

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

To determine the suitability of dimethyl sulfoxide (DMSO) as a solvent for photo polymerization, solutions of wheat gluten protein (0.28-0.93% by weight) and styrene (4.13-12.65% by weight) in DMSO were irradiated by a 200.W high-pressure mercury arc lamp from 3 min up to 1 hr. Graft copolymers of gluten styrene resulted that contained styrene residues ranging from 2 to 23% by weight. When gluten protein was photolyzed in DMSO alone, a significant amount of sulfur from the solvent was incorporated; however, styrene successfully competed with the solvent for free radical sites. The rate of grafting was directly related to both the concentration of gluten and of styrene. Also, the ratio of grafted polystyrene to gluten in the graft polymer indicated that the grafts were composed of small units of polystyrene.

ISSN:0022-233X    

DOI:10.1080/00222337008060989

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor