THE PHOTOCHEMICAL SYNTHESIS OF THE PYRIDINE ADDUCT OF TETRAPHENYLPORPHYRINATORHODIUM(Ⅱ)AND THE MECHANISM OF PHOTOCHEMICAL REACTION

A new rhodium(Ⅱ)porphyrin complex was isolated by chromatography from the photochemical reac-tion of(μ—tetraphenylporphyrinato)bis[dicarbonylrhodium(Ⅰ)]with pyridine in benzene and has been charac-terized.From the results,the reaction mechanism is proposed.     

ON THE MECHANISM OF “HYDROPHOBIC” INTERACTIONS

It is shown that the interfacial attraction between low-energy bodies immersed in aqueous media, known as “hydrophobic” interaction, can be quantitatively accounted for by, mainly, the hydrogen-bonding energy of cohesion of water, plus, to a very minor extent, a van der Waals-Lifshitz attraction between the Immersed law-energy bodies.     

THE MECHANISM OF COPOLYMERIZATION OF VINYL AND DIVINYL MONOMER Ⅵ: A STUDY ON THE MECHANISM OF THE STRUCTURE FORMATION OF CROSSLINKED POLYSTYRENE

In order to study the mechanism of the formation of maeroporous copolymer, the overall reaction kinetics, phase separation and gelation of the S/EGDM in the presence of inert solvents and the physical properties of the eopolymer were investigated and compared with the corresponding system of S/DVB and S/DVB/MMA. The formation of the network structure of the macroreticular polymer was studied and a model of the mechanism suggested.     

STUDIES ON THE PHOTOCHEMICAL REACTION OF TERTIARY AROMATIC AMINES AND ALIPHATIC HALIDES——STRUCTURE OF THE PRODUCT AND MECHANISM OF THE REACTION

The photochemical reaction of aromatic amines in the presence of aliphatic halides and molecular oxygen were studied. There is a very obvious structural effect of amines on the photoreactions, and the purple products, formed only in the tertiary aromatic amines system, were proved to be amiuium radical salts, e. g. CH_3—(CH_3)_2Cl-by moans of UV, NMR and ESR spectroscopies electronic conductivity and chemical analysis. The purple product can oxidize the adrenaline to adrenochrome. The mechanism of the photoreaction and the oxidation were discussed.     

A NUMERICAL STUDY ON THE MECHANISM OF BLOCKING HIGH FORMATION

Numerical integration is performed of the KDV equation of the forced dissipation with the result that it takes about 10 days to transform a high-index circulation into a blocking pattern, in whose establishment and maintenance the thermal forcing and dissipation, nonlinoear advection, and linear dispersion are equally important and serve as three factors of essentiality.     

PRELIMINARY STUDY ON MECHANISM OF PLANT ROOTS TO INCREASE SOIL ANTISCOURIBILITY ON THE LOESS PLATEAU

The effects of the root system of trees, shrubs and grasses on the hydraulic andphysical properties of soil and their interrelation with increasing soil anti--scouribility byroots are quantitatively demonstrated in this paper for the first time. Based on the analysisof the leading factors of roots to increase the soil anti--scouribility, a mathematical modelon increasing soil anti-scouribility by roots is established. The value in application of themodel is to explain the mechanism of roots to increase the soil anti-scouribility and toevaluate the increasing effects of soil anti-scouribility by roots in different layers of soilThe calculated results of the values in soil anti--scouribility intensified by roots at variousintensities of rainfall and slopes of the model have higher precision, all of the meanmaximum deviations between the estimated and observed values being less than 1.417 s/g.     

APPLICATION OF SIMPLEX-DEVIATION-PATTERN RECOGNITION TO THE CONFIRMATION OF THE ELECTRODE REACTION MECHANISM

Three hypotheses of the electrochemical reaction mechanism of theDy(III)-ALC complex were put forward,based on the experimental results.Thenit has been confirmed by simplex-deviation-pattern reoognition that the pola-rographic wave of the Dy(III)-ALC complex was an adsorptive-complex wave.     

INSERTION REACTION OF CARBOETHOXYLCARBENE TO N-HEXANE IN THE PRESENCE OF BENZOPHENONE AND THE SENSITIZED PHOTO-OXIDATION OF N-HEXANE

In the presence of protosensitizer-benzophenone, ethyl diazoacetate was photolyzedand the resulting carboethoxylcarbene reacted with n-hexane. The result was compared withthat done without the sensitizer. It was revealed that the nature of the insertion products andtheir relative proportions remained the same, whether the sensitizer was presentor not. At the same time, the influence of oxygen on the sensitized and unsensitized inser-tion reaetions was also studied; these showed also no influence on the nature of insertionproducts and their relative proportions no matter whether the sensitizer or oxygen was pres-ent or not. Since oxygen ks a well-known seavenger for the triplet state carbene, the ex-perimental results indicate clearly that the insertion reactions are conducted by the carbenein singlet state. The photo-oxidation products of n-hexane sensitized by air in the presence of benzophe-none were carefully studied, showing that the primary hexyl radical seemed to be rearrang-ed to thermodynamicall     

APPLICATION OF FULLERENES TO THE STUDY ON ITIES Ⅰ:INHIBITION TO THE TRANSFER OF TMA~+

For the first time,fullerenes are applied to the study on the interface between twoimmisible electrolyte solutions.Experiments show they are a new kind of inhibitors.Obvious inhibitive behavior to the TMA~+ transfer across the water/nitrobenzeneinterface is observed.     

STUDIES ON THE INCORPORATION OF MEMBRANE PROTEINS INTO LIPOSOMES

The reactivation of delipidated cytochrome oxidase depends on the reformation of "an-nular lipids", which is tightly bounded to the enzyme molecule. In the restoration of oxidase activity, the efficiencies of phospholipids with differentpolar head groups decrease in this order: PS>DPG>PI>PA>PG>PC, PE and inthe case of phosphatidyleholines with differentt acyl chain the order is: DOPC>LPC>PC>DPPC, DSPC. Therefore both the polar head group and the acyl ehain of phospholipidsmust be considered in the reactivatioll process. The existence and fhe specificity of "anuular lipids' obviously influence the incorpora-tion of cytochrome oxidase into liposomes. When acidic phospholipids are used as "annularlipids", the effectiveness of reconstitution decreases in this order: PI>PS>DPG>PA,PG. Divalent metallic cations would facilitate the cytochrome oxidase reconstitution, but theireffects depend on the composition of "annular lipids". Using dialysis method Ca~(2 ) andMg~(2 ) could facilitate the incorporation into liposomes of tlle enzymes having PS or DOPCas their "boundary lipids". A comparison between the effects of different metallic cations on incorporation of cyto-cbrome oxidase also shows that, with PI as "annulay lipids", the effectiveness of differentcations on incorporation by incubation method decreases in this order: Ca~(2 )>Mg~(2 )>Mn~(2 ),Sr~(2 )>La~(3 ). Apparently, the effect of metallic cations on incorporntion cannot be inter-preted by considering only the neutralization of the negative charged groups on membraneprotein and lipids.     

STUDY ON THE ADDITION REACTION OF 1-IODO-4-CHLOROPERFLOROBUTANE TO 1-HEXENE UNDER REDUCTIVE CONDITIONS

Promoted by various reductants,the addition of 1-iodo-4-chloro-perfluorobutane to 1-hexene giving 1:1 adduct is reported.Based on thesefacts,several new redox systems are proposed.     

AN ANALYSIS ON THE EQUIVALENCE OF THE EYE TO A SYSTEM WITH ABERRATION

Computed transfer functions for ε=0.60 and 0.75 annular pupils of 2.67 mm o.d. showthat absorption of the average spherical aberration of the eye is still incomplete but if theeye is so designed as to adjust its focal plane in order to achieve a best Strehl ratio, itwould show a transfer function approaching that of a diffraction limited system, i.e. the opticaldefect of the eye is overcompensated. However, it is argued that a varying amount offocusing adjustment of the eye is needed in order to account for the transfer function ofthe eye of different pupil sizes, though not always to the extent of achieving a best Strehlratio. Such a property of the eye is referred to variously as the antidefocusing, deblurringor contrast constancy phenomenon and, when operationally defined, this is equivalent to sayingthat the eye has a greater depth of focus than that defined for a physical system based upona fixed demodulation criterion. The signifi ance of the physiological depth of the eye isdiscussed.     

A STUDY ON THE CHEMICAL MECHANISM FOR POWDER CORROSION OF BRONZE ALLOY

A Cu-Sn-Pb alloy modelled after an antique was cast and the powder-corrosion (P-C) was prepared on it under simulated natural conditions. The main components of the corrosion are much like those of the ancient bronze powder corrosion. It is found that chloride, water and oxygen are the essential factors for P-C formation of which chlorine plays the most important role. According to the results of expriments and thermodynamic calculations, the chemical mechanism of the copper desease was studied. It is pointed out that the fast spread of P-C is caused by two vicious circles.     

EFFECT OF PHOSPHORUS ADDITION TO SILICA ON CATALYTIC PROPERTIES FOR PARTIAL OXIDATION OF METHANE TO FORMALDEHYDE

lntroductionForthepartialoxidaionofmethanetoformaldehydeacatalystthatfacilitatestheformationofformaldehydewithoutcataIyzingitsfurtheroxidaiontocarbon0xidesisrequired.Effortshavebeenextensivel}'tryingforthisreactionbyusingsilicasupportedmetaloxidesespeciallym0l}'bdenumoxidecataly'stswithdioxygenastheox}'gensourccunderatmosphericconditions.However,mostofthelitefatureresultsshowedvery'l0tvHCH0selectivitiesdcspiteofthehighCH4conversionsandthereforeHCH0yieldsweregenerallybelow2%.Inourpreviousx`…     

STUDY ON THE TOUGHENING MECHANISM OF RUBBER TOUGHENED EPOXY

The following factors affecting the rubber toughened epoxy resin system were studied: 1. kindsof curing agent used, 2. the M_c value of the matrix, 3. the bonding foce between the dispersed phaseand the matrix. Our experimental result indicates that the average chain length between crosslinks(M_c) is a much more important affecting factor. Chemical bonding between the dispersed phaseand the matrix is also important. A toughening mechanism of rubber toughened epoxy has beenproposed. In the material with relatively low crosslinking density, extensive fracture process stripis formed which is induced by the combined stress field near the rubber particles. The chemical bond-ing between the dispersed phase and the matrix may inerease the strength of the local stress field aboutthe rubber particles which is in favor of broading the fracture process area.     

ON THE ORIGIN OF THE CONFIGURATIONAL STABILITY OF CARBANIONS α TO SULFOXIDES : SPECTROSCOPIC STUDIES

Abstract

In recent papers (1–2), we have shown that the metalated carbon in α lithiosulfoxides is essentially planar, this structure being induced by the internal chelation of the cation. The stereoselectivity of the alkylation of these species is very well rationalized on this basis (3).     

THE ELECTRON SPIN RESONANCE STUDY ON PRIMARY PHOTOCHEMICAL REACTION OF HEMATOPORPHYRIN DERIVATIVE

The rate of oxygen consumption and the yield of free radical anion of hematoporphyrin derivative (HPD) in aqueous solutions of HPD and pyrocatechol were measured by the probe 2,2,6,6-tetramethyl4-piperidone-1-oxyl.It has been found that both singlet oxygen and free radical mechanisms exist simultaneously in primary photochemical reactions, and there is a competition between both mechanisms. When the oxygen concentration in solutions comes down to 12-14% of the stanting level, the predominant mechanism can be changed from the singlet oxygen to the free radical.Whether HPD exists in aggregation state is very important to photosensitization mechanisms.In the presence of the aggregation state of HPD, the predominant mechanism is the free radical,and photosensitization effects of HPD are all the better.     

STUDY ON THE PROTONATION MECHANISM OF 2,6-DIMETHYL NAPHTHALENE DICARBOXYLATE

By the study of absorption and fluorescence spectra and the lifetime of fluorescence at room and low temperatures of 2,6-dimethyl naphthalene dicarboxylate (DMN) in different concentrations of sulfuric acid, different interactions between molecules of DMN and sulfuric acid have been observed. These interactions have been revealed by the absorption spectra of charge transfer complex in the ground state, emission of exciplex, absorption spectra of hydrogen bonding interaction, absorption and emission spectra after proton transfer and different lifetimes before and after protonation. The interaction mechanism of DMN and sulfuric acid through first the CT complex and exciplex then hydrogen bonding and finally proton transfer is proposed.     

OBSERVATION OF A COMPETITIVE PATH IN THE NUCLEOPHILIC ADDITION REACTION OF FLUOROOLEFINS:THE BROMOPHILIC REACTION OF THE ADDUCT CARBANION INTERMEDIATE

The nucleophilic addition reaction of per-or polyfluoroolefins with nucleophileshas been studied extensively and is generally considered to involve steps such as(1),(2)and(3)shown in Scheme 1.But in the reactions of bromotrifluoroethene(3)with alkoxides RO~-(2),besides the normally expected products ROCF_2CFBrH(4)     

THE EFFECT OF SENSITIZERS ON PARTIAL OXIDATION OF METHANE TO FORMALDEHYDE

Ketone was the optimum sensitizer selected from many additives. With ketonc as the additive, the yield of formaldehyde was more than 2.40% and the highest yield Was 3.58% over the silica gel-1 catalyst, and remained almost unchanged during the catalyst life test of 500 h. Ketone can compensate the catalyst for the -OH loss shown by 1R, TGA and XPS of the catalysts before and after the reaction.