Studies on the Autoxidation of Phenyl Cycloalkanes

The products of the autoxidation of phenyl cyclopropane ( I ), phenyl cyclobutane ( II ), phenyl cyclopentane ( III ), phenyl cyclohexane ( IV ), phenyl cycloheptane ( V ) and phenyl cyclooctane ( VI ) were analyzed after reduction of the reaction mixtures with LiAlH₄. As products of the attack on the α-C H bonds the corresponding 1-phenyl cycloalkanols and 1-phenyl alkan-1-ols were found. In the case of phenyl cyclopropane some S_R2 ring opening probably takes place. The oxidabilities $ {\rm k}_{\rm p} /\sqrt {{\rm k}_{\rm t}} $, the chain termination constants k_t, the absolute chain propagation constants k_p and the relative chain propagation constant (k_p)_rel were determined for the phenyl cycloalkanes I — VI . As it is to be expected on the basis of the I-strain concept the autoxidation rate of phenyl cyclopentane ( III ) is considerably higher than that of phenyl cyclobutane ( II ) and phenyl cyclohexane ( IV ).     

Studies on the Autoxidation of Aryl Alkenes

Autoxidation activity of substituted styrenes (aryl alkenes) and their product formation were studied in the temperature range of 65–125 °C using cumene or chlorobenzene as solvent. It was observed that higher reaction temperatures, inert solvent, electron donating substituents, and bulky sterical groups at α‐, ortho‐ and para‐ positions promoted radical formation of epoxides and led to C=C oxidative cleavage. In contrast, electron accepting substituents and using cumene as the solvent favored the formation of oligomeric peroxides. The relative activity of all investigated styrenes could be correlated to the linear free energy (LFE) relation and the ionization potential. For α‐substituted styrenes and ring substituted α‐methylstyrenes LFE correlation for the reactivity of aryl alkenes and formation of epoxides was found to depend on the polar and steric factors. A general pathway for product formation by autoxidation of aryl alkenes has been proposed.     

苯乙炔的合成研究

苯乙烯与溴在四氯化碳中于１０～１５℃反应生成１,２ 二溴乙苯,后者与氢氧化钾在甲醇中回流脱溴化氢生成苯乙炔,总收率６０％。     

On the Autoxidation of Vitamin D Preparations II: The Autoxidation of Ergocalciferol

Ergocalciferol was used as a model for the autoxidation studies of vitamins D. It was shown that ergocalciferol is sensitive to light, moisture and heat in the addition of oxygen. The autoxidation proceeds through isomerisation to carbonyl compound formation without the development of peroxidic groups.     

苯乙炔半加氢催化剂研究进展

对苯乙烯的生产现状进行了说明,并对从裂解汽油中获得苯乙烯的应用前景进行了分析;重点对国内外的最新苯乙炔加氢催化剂的前沿研究进行了报道,从贵金属催化剂、非贵金属催化剂的角度进行了分析,详细介绍了一些具有新颖性的催化剂的制备方法,并对催化剂的使用条件、性能及对苯乙烯的选择性进行了分析。     

Autoxidation of polyunsaturated fatty esters on Silica

The stability of unsaturated methyl esters of fatty acid adsorbed on silica gel and silicic acid was studied by gas liquid chromatographic estimation of disappearance relative to a saturated internal standard. Variables included silica-ester ratio, agitation, adsorbent particle size, and degree of unsaturation. Under the conditions of the experiment, destruction of substrate unsaturated ester at 80 C was more a function of time than of unsaturation or initial purity.     

Autoxidation of phosphatidylcholine liposomes

Autoxidation of pure soybean phosphatidylcholine liposomes at 40 C was found to proceed without an observed induction period, but otherwise, the rates of disappearance of the linoleic acid (70% of total) and linolenic acid (6% of total) followed typical autocatalytic kinetics. Incorporation of 0.05 mol % of tocopherol into the liposomes produced an induction period of about 7 hr under the condition used for the incubation. The produts formed from the autoxidation of pure soybean phosphatidylcholine liposomes were mostly 9- and 13-hydroperoxyoctadecadienoates (isolated as hydroxy esters). The yield of hydroperoxides withcis,trans configuration was about the same as those withtrans,trans configuration throughout incubation period. After extensive autoxidation, a large quantity of trihy droxyoctadecenoate was also produced. When a large quantity of dipalmitoyl phosphatidylcholine was incorporated into soybean phosphatidylcholine liposomes, the rate of autoxidation decreased and was found to conform to apparent first-order kinetics. In this system, the yield oftrans, trans hydroperoxides was much greater than that ofcis,trans isomers at all stages of autoxidation. Late in the autoxidation of the mixed liposomes, both trihydroxyoctadecenoate and hydroxyepoxyoctadecenoate were produced in substantial quantities.     

Autoxidation of semicrystalline polyethylene

Thermal oxidation in linear polyethylene is mainly confined to disordered regions in which scission reactions cause crystallization and eventual deterioration of mechanical properties. Gel formation is negligible at 100°C. As degradation proceeds, comparable changes occur in the intrinsic viscosities of melt and solution-crystallized liner polymers, indicating that chain folds are regularly arranged and are resistant to oxidative scission. Breakdown is much more extensive in branched and crosslinked polymers since crosslinking retards oxidative crystallization and branching increases the volume fraction of substrate ultimately accessible to oxygen.     

Autoxidation of drying oils adsorbed on porous solids

Summary The rate of oxygen uptake of purified soybean oil was determined as a function of the dispersion of the oil on the surface of highly porous silica gel. The most rapid consumption of characteristic of the specific surface areas of the adsorbents. At these critical concentrations it was shown that the oil constituted a closely packed monomolecular layer. The existence of such critical ratios was regarded as further substantiation of the radical chain mechanism of autoxidation. Contribution from the Multiple Fellowship on Cork sustained at Mellon Institute by the Armstrong Cork Company, Lancaster, Pa. A portion of a thesis submitted by F. J. Honn to the faculty of the Department of Chemistry of the University of Pittsburgh in partial fulfillment of the requirements for the Ph.D. degree. Another portion of this thesis was recently published by Honn, Bezman, and Daubert,J. Am. Chem. Soc., 71, 812 (1949).     

苯乙烯存在下的苯乙炔选择性加氢技术

去除苯乙烯(ST)中的苯乙炔(PA)是生产高品质苯乙烯单体产品的重要环节。除去苯乙烯中苯乙炔杂质的最有效的主要方法是将苯乙炔在催化剂的作用下，将其选择性加氢转化成苯乙烯。本文较详细地介绍了当前各专利厂商的苯乙炔选择性加氢催化剂的开发研究情况。主要对各种催化剂的制备方法、操作条件和主要问题进行了介绍。另外介绍两种苯乙烯存在下苯乙炔选择性加氢的工艺过程。最后对几种适用于不同操作条件下的催化剂进行了对比，指出了今后研究工作的重点。     

Autoxidation ofAcholeplasma laidlawii membranes

Autoxidation ofAcholeplasma laidlawii membranes (with equimolar ratio of palmitic and linoleic acid) lacks an obvious induction period, and the overall rate of disappearance of substrate does not follow closely that of typical autocatalytic kinetics. Throughout the course of autoxidation, the major oxygenated products isolated were hydroperoxides (as hydroxy esters) and compounds that gave rise to trihydroxy esters. The yield of trihydroxy esters was appreciable even at the early stage of the oxidation and eventually grew to surpass that of hydroperoxides. The positions of the three hydroxyl groups in the trihydroxy esters were determined to be mostly of the 1,2,5-type rather than 1,2,3-type arrangement. To a lesser extent, some degraded products, including dimethyl nonanedioate, methyl myristate, methyl pentadecanoate, methyl hexadecadienoate and methyl heptadecadienoate also were obtained. Dimethyl nonanedioate was a previously known degradation product from 9-hydroperoxide. The shorter chain esters presumably arise from the cleavage of α-hydroperoxides of palmitate and linoleate moieties.     

Autoxidation products of 2,4-decadienal

2,4-Decadienal was autoxidized by purging a purified sample with oxygen. An analysis of the autoxidative degradation products was made with tandem gas chromatography-mass spectrometry. Additional information was obtained from the determination of the melting point of the dinitrophenylhydrazone derivatives and IR absorbency data. Pentane, furan, ethanal, hexanal, acrolein, butenal, 2-heptenal, 2-octenal, benzaldehyde, glyoxal,trans-2-buten-1,4-dial, acetic acid, hexanoic acid, 2-octenoic acid, 2,4-decadienoic acid and benzene were identified. Technical Paper No. 3069, Oregon Agricultural Experlment Station.     

Autoxidation products from cholesterol

Thin-layer chromatography and gas-liquid chromatography were used to separate and identify products from the autoxidation of cholesterol. Both cholesterol-a-epoxide and 1,4-cholestadien-3-one were found. In addition, several other compounds, identified also by previous workers, were shown to be present. Autoxidation in bulk was quite slow at 82C, requiring several weeks for development of detectable quantities of decomposition products. The reaction could be accelerated by irradiation with ultraviolet light or by heating the sterol above its melting point.     

苯乙炔选择性加氢催化剂的研究进展

对各种苯乙炔选择性加氢催化剂的开发研究情况进行了详细介绍。由于负载型钯催化剂和镍催化剂在加氢反应领域应用广泛,本文对这两种催化剂进行了重点介绍。阐述了各种催化剂的性能、使用条件、存在的主要问题、失活原因以及改进措施。提出今后对苯乙炔选择性加氢催化剂的改进应以高空速、适当提高操作温度、改善对原料的适应性等为目标。     

一种新型不对称芳炔半环化合物的合成

以间二碘苯为原料,通过Sonogashira反应,合成了一种不对称芳炔半环化合物:1-{3-溴-5-[2-(2-乙氧基乙氧基)乙氧基]苯基}乙炔基-3-{3-[(3,3-二乙基)三氮烯]-5-[2-(2-乙氧基乙氧基)乙氧基]苯基}乙炔基苯,并对合成路线的选择和反应条件进行了比较和讨论。用1H NMR,13C NMR,质谱,元素分析等表征手段确认了中间体及最终产物的结构。     

The Autoxidation of Tensides I: The Autoxidation,Toxicity and Reclamation of Dianhydro Mannitol Mono-Oleate

Dianhydro mannitol mono-oleate, a surfactant used in the preparation of water-in-oil injectable pharmaceutical preparations was found to autoxidize on storing, with the formation of free acidity and labile peroxides. The autoxidized substance was found to cause peritoneal adhesions when injected intraperitoneally in mice. The autoxidized material could be reclaimed by chromatography through alumina. The eluate was comparable to normal saline in toxicity and the adsorbate was found to be more toxic.