Journal of the Chemical Society, Faraday Transactions最新文献_第2页

Benzene–chloroform association Excess molar enthalpy of (cyclohexane+chloroform)(g) and (benzene+chloroform)(g) at temperatures from 353.2 to 423.2 K (环己烷+氯仿)(g)和(苯+氯仿)(g)在353.2 ~ 423.2 K温度下的过量摩尔焓

Journal of the Chemical Society, Faraday Transactions Pub Date : 1998-01-01 DOI: 10.1039/A708601F

C. Wormald, P. Johnson

{"title":"Benzene–chloroform association Excess molar enthalpy of (cyclohexane+chloroform)(g) and (benzene+chloroform)(g) at temperatures from 353.2 to 423.2 K","authors":"C. Wormald, P. Johnson","doi":"10.1039/A708601F","DOIUrl":"https://doi.org/10.1039/A708601F","url":null,"abstract":"A flow-mixing calorimeter has been used to measure the excess molar enthalpy HmE of (cyclohexane+chloroform)(g) and (benzene+chloroform)(g) at standard atmospheric pressure over the temperature range 353.2–423.2 K. The non-ideality of the cyclohexane and benzene was fitted using the Kihara potential, and that of the chloroform using the Stockmayer potential. Cross-terms were calculated using the equation e12=(1-k12)(e11e22)1/2 and to fit the measurements on (cyclohexane+chloroform)(g) the value (1-k12)=0.965 was needed. This value was used to calculate HmE for (benzene+chloroform)(g), and the calculated values were found to be positive and to be similar to those for (cyclohexane+chloroform)(g). However, the experimental values are negative, and about 35 J mol-1 below the values for (cyclohexane+chloroform)(g). The difference between the calculated and experimental values was described in terms of a quasi-chemical model that, for the benzene–chloroform interaction, yielded a value of the equilibrium constant K12(298.15 K)=0.373 MPa-1 and an enthalpy of association ΔH12=-(16.1±2) kJ mol-1. This value of ΔH12 is attributed to a charge transfer between the benzene and the chloroform that is not present in the cyclohexane–chloroform interaction.","PeriodicalId":17286,"journal":{"name":"Journal of the Chemical Society, Faraday Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73112506","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Thermodynamics and kinetics of flavylium salts Malvin revisited 重述黄盐的热力学和动力学

Journal of the Chemical Society, Faraday Transactions Pub Date : 1998-01-01 DOI: 10.1039/A802602E

F. Pina

引用次数: 61

Enhancement of the catalytic activity of VPO ammoxidation catalysts by use of vanadyl(IV) orthophosphate precursor compounds 正磷酸钒基前体化合物增强VPO氨氧化催化剂的催化活性

Journal of the Chemical Society, Faraday Transactions Pub Date : 1998-01-01 DOI: 10.1039/A801531G

Andreas Martin, G. Wolf, U. Steinike, B. Lücke

{"title":"Enhancement of the catalytic activity of VPO ammoxidation catalysts by use of vanadyl(IV) orthophosphate precursor compounds","authors":"Andreas Martin, G. Wolf, U. Steinike, B. Lücke","doi":"10.1039/A801531G","DOIUrl":"https://doi.org/10.1039/A801531G","url":null,"abstract":"(VO)3(PO4)2·7H2O and (VO)3(PO4)2·9H2O vanadyl(IV) orthophosphate hydrates (V/P = 1.5) used as precursor compounds were transformed into highly active ammoxidation catalysts during different pretreatment procedures. These structural transformations have been investigated in the presence of ammonia-containing gases or under nitrogen, leading into materials that contain crystalline (NH4)2(VO)3(P2O7)2 (V/P = 0.75) and (VO)2P2O7 (V/P = 1) specimens, respectively, as well as an additional X-ray-amorphous phase of partially crystalline vanadium oxides. These vanadium oxides represent the molar vanadium excess of the original precursor material in comparison to the defined vanadium amount of the crystalline proportion of the transformation product. Both components of these solids are tightly grown together to form microdomains. The solids generated this way were characterized by XRD, EDX, FTIR spectroscopy, 31P MAS NMR spectroscopy, XPS and chemical analyses and used as catalysts in the ammoxidation of toluene to benzonitrile. The results of the heterogeneous catalytic ammoxidation on the orthophosphate derived catalysts were compared with those runs obtained by the application of pure, as-synthesized (NH4)2(VO)3(P2O7)2, similar transformation products derived from VOHPO4·0.5H2O precursor (V/P = 1) and pure (VO)2P2O7. Owing to the existence of mixed-valent vanadium oxides in increased portions of the orthophosphate derived catalysts, these solids reveal a significant enhancement of the toluene conversion rate at almost equal high nitrile selectivities in comparison to usual VPO catalysts.","PeriodicalId":17286,"journal":{"name":"Journal of the Chemical Society, Faraday Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75728139","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 22

Mechanistic aspects of anisotropic dissolution of materials Etching of single-crystal silicon in alkaline solutions 单晶硅在碱性溶液中的蚀刻

Journal of the Chemical Society, Faraday Transactions Pub Date : 1998-01-01 DOI: 10.1039/A707473E

T. Baum, D. Schiffrin

引用次数: 38

Diffusion of electrically neutral radicals and anion radicals created by photochemical reactions 由光化学反应产生的电中性自由基和阴离子自由基的扩散

Journal of the Chemical Society, Faraday Transactions Pub Date : 1998-01-01 DOI: 10.1039/A706220F

K. Okamoto, N. Hirota, and Masahide Terazima

引用次数: 8

Brnsted acidity of extraframework debris in steamed Y zeolites from the FTIR study of CO adsorption 从CO吸附的FTIR研究蒸Y沸石中骨架外碎屑的brsted酸度

Journal of the Chemical Society, Faraday Transactions Pub Date : 1998-01-01 DOI: 10.1039/A803886D

O. Cairon, J. Lavalley

引用次数: 107

Thermodynamics and kinetics of sugar phosphate binding to D-ribulose 1,5-bisphosphate carboxylase/oxygenase (RUBISCO) 磷酸糖与d -核酮糖1,5-二磷酸羧化酶/加氧酶(RUBISCO)结合的热力学和动力学

Journal of the Chemical Society, Faraday Transactions Pub Date : 1998-01-01 DOI: 10.1039/A802124D

J. Frank, J. Vater, J. Holzwarth

{"title":"Thermodynamics and kinetics of sugar phosphate binding to D-ribulose 1,5-bisphosphate carboxylase/oxygenase (RUBISCO)","authors":"J. Frank, J. Vater, J. Holzwarth","doi":"10.1039/A802124D","DOIUrl":"https://doi.org/10.1039/A802124D","url":null,"abstract":"It has been demonstrated by microcalorimetric and fast reaction techniques that D-ribulose 1,5-bisphosphate carboxylase/oxygenase (RUBISCO) from spinach shows strong and weak binding sites for the substrate D-ribulose 1,5-bisphosphate (RuBP), for the effector 6-D-phosphogluconate (6-PG), and for the so called ‘transition state analogue’ 2-carboxy-D-arabinitol 1,5-bisphosphate (CABP). The stoichiometry n, the dissociation constant Kd and the enthalpy change ΔHb associated with the strong binding of RuBP and CABP to RUBISCO were measured by isothermal differential titration calorimetry. In addition, differential scanning calorimetry showed an increase of the thermal stability of RUBISCO in the presence of RuBP, 6-PG and especially CABP. The kinetics of binding of RuBP and 6-PG to RUBISCO were measured by stopped flow and iodine laser temperature jump experiments using the fluorescence probe 2-(p-toluidinyl)naphthalene-6-sulfonate. The kinetics of the reversible bimolecular binding reactions of RuBP and 6-PG revealed a fast and a slow phase corresponding to the strong and weak ligand binding phenomena observed in equilibrium measurements. The association and dissociation rate constants k+ and k- for these processes were determined. The dissociation constants Kd calculated from the kinetic constants are in good agreement with Kd values obtained from calorimetric and fluorescence titration studies.","PeriodicalId":17286,"journal":{"name":"Journal of the Chemical Society, Faraday Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75092807","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 11

Determination of the limiting low pressure rate constants of the reactions of CH with N2 and CO: a CRESU measurement at 53 K 53 K条件下CH与N2、CO反应极限低压速率常数的CRESU测定

Journal of the Chemical Society, Faraday Transactions Pub Date : 1998-01-01 DOI: 10.1039/A803930E

S. Picard, A. Canosa, B. Rowe, R. Brownsword, I. Smith

{"title":"Determination of the limiting low pressure rate constants of the reactions of CH with N2 and CO: a CRESU measurement at 53 K","authors":"S. Picard, A. Canosa, B. Rowe, R. Brownsword, I. Smith","doi":"10.1039/A803930E","DOIUrl":"https://doi.org/10.1039/A803930E","url":null,"abstract":"The pulsed laser photolysis, time-resolved laser-induced fluorescence technique has been implemented in a CRESU (Cine′tiquedeRe′actionenEcoulementSupersoniqueUniforme) apparatus to measure the rates of the association reactions of CH radicals with N2 and CO at 53 K and five different densities of the carrier gas Ar. The pressure-dependent rate constants have been combined with those reported previously for the temperature range 202⩽T/K⩽584 (R. A. Brownsword, L. B. Herbert, I. W. M. Smith and D. W. A. Stewart, J. Chem. Soc., FaradayTrans., 1996, 92, 1087) to yield, via a global fitting procedure, the following expressions for the two rate constants in the limit of low pressure: These expressions are very similar to those deduced previously by Brownsword etal., demonstrating that the analysis of rate constants for association reactions by the methods proposed by Troe (J. Chem. Phys., 1977, 66, 4758) can be applied over a wide range of temperature. These low temperature kinetic data, especially those for CH+N2, have some relevance to the chemistry of the atmospheres of some planets and planetary moons.","PeriodicalId":17286,"journal":{"name":"Journal of the Chemical Society, Faraday Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72680039","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 20

Self-abstraction in aliphatic hydroperoxyl radicals 脂肪族羟基自由基的自抽离

Journal of the Chemical Society, Faraday Transactions Pub Date : 1998-01-01 DOI: 10.1039/A803344G

Wai-To Chan, I. Hamilton, H. O. Pritchard

引用次数: 23

Kinetics of excited-state Cr(a5DJ, a5S2) depletion by O2, NO, and N2 Cr(a5DJ, a5S2)在O2, NO和N2作用下耗竭的激发态动力学

Journal of the Chemical Society, Faraday Transactions Pub Date : 1998-01-01 DOI: 10.1039/A800201K

C. Haynes, K. Honma

引用次数: 12