溶胶－凝胶法制备的包容β－二酮钴催化剂在二苯甲醇氧化反应中的催化性能

 采用溶胶－凝胶法分别以SiO2，Al2O3和TiO2为基体包容β－二酮钴配合物制备了非均相催化剂，采用FT－IR，TG－DTA，XPS及N2吸附方法对以SiO2为基体包容的乙酰丙酮合钴配合物Co（acac）2／SiO2进行了表征，并通过空气氧化二苯甲醇合成二苯甲酮反应评价了催化剂的催化性能．结果表明，Co（acac）2／SiO2的催化性能最好，其玻璃性能也最好．用Co（acac）2／SiO2作为催化剂反应12h后，二苯甲醇的转化率为95．7％，与均相催化反应相比没有明显降低，而且循环利用7次后其催化性能保持不变．包容催化剂的活性依赖于包容基体及其比表面积．     

Co/γ-Al_2O_3催化剂上肉桂醛的选择加氢──反应性能的考察

研究了γ－Al2O3负载的Co／γ－Al2O3催化剂上肉桂醛的选择加氢反应．反应结果表明,以CoCl2作为前驱物的Co／γ－Al2O3催化剂的选择性要高于以Co（NO3）2作为前驱物的Co／γ－Al2O3催化剂,而活性则正好相反．当钴的负载量小于9％时,随着钴负载量的增加,催化剂的活性和选择性随之增加,当钴的负载量大于9％时,随着钴负载量的增加,Co／γ－Al2O3催化剂的活性略有增加,而生成肉桂醇的选择性变化也很小,认为9％的钴负载量是催化剂反应活性和选择性的一个阈值．在所选定的范围内,反应温度和压力对肉桂醛加氢的选择性几乎没有影响．     

溶胶凝胶包埋吡啶羧酸钴及其对甲醇氧化羰化反应的催化性能

 以正硅酸乙酯为前驱体，采用溶胶－凝胶技术将吡啶羧酸钴包埋进SiO2基体中，于80℃干燥12h后得到钴含量为2．8％（Co／Si摩尔比）的干凝胶催化剂．采用FT－IR和TG－DTA方法对包埋催化剂进行了表征，考察了成胶过程中的pH和水与正硅酸乙酯的摩尔比（R）对包埋催化剂的结构及其对甲醇氧化羰化制碳酸二甲酯反应催化性能的影响．结果表明，干凝胶催化剂有较高的比表面积（320～458m2／g）．在酸性条件下，增大pH或减小R值可缩短成胶时间．最佳的包埋条件是pH＝4，R＝6，在此条件下制备的凝胶包埋催化剂的活性最高，反应3h，甲醇转化率为5．73％，略低于均相催化剂上的甲醇转化率．但凝胶包埋催化剂分离简便，且重复使用6次后活性保持不变．     

双（呋喃甲醛）缩二胺钴（II）配合物的合成及其氧合和催化氧化性能研究

合成和表征了氯化双（呋喃甲醛）缩邻苯二胺合钴（II）（1）、氯化双（呋 喃甲醛）缩乙二胺合钴（II）（2）、氯化双（呋喃甲醛）缩1，2-丙二胺合钴（ II）（3）和氯化双（呋喃甲醛）缩1，3-丙二胺合钴（II）（4）。在吡啶溶液中 和不同温度下，测定了配合物的饱和吸氧量，求出了氧加合常数和热力学参数ΔH °，ΔS°。并以这些配合物为催化剂，活化分子氧氧化环已烯得到高选择性的烯 丙位氧化产物。讨论了温度、配体结构对配合物氧合性能的影响和配体结构以及添 加NHPI（N-羟基邻苯二甲酰亚胺）对环已烯氧化反应的影响。     

铁（Ⅲ）、钴（Ⅱ）和镍（Ⅱ）的三（2－苯并咪唑甲基）胺配合物催化环己烯的氧化反应

铁（Ⅲ）、钴（Ⅱ）和镍（Ⅱ）的三（２－苯并咪唑甲基）胺配合物催化环己烯的氧化反应吕正荣，殷元骐，金道森（中国科学院兰州化学物理研究所，兰州７３００００）关键词铁（Ⅲ）配合物，钴（Ⅱ）配合物，镍（Ⅱ）配合物，环己烯氧化反应．与含血红素的氧化酶相比，人们...     

二氯·{2-乙氧甲酰基-6-[1-[(2,6-二乙基苯)亚胺基]乙基]吡啶}合钴(II)的晶体结构极其对乙烯齐聚的催化活性

利用2,6-二甲基吡啶作为起始物合成了不对称前驱体6-乙酰基-2-乙酯基吡啶，在此基础上合成了单亚胺吡啶配体（5）和相应的Co(II)配合物二氯·{2-乙氧甲酰基-6-[1-[(2,6-二乙基苯)亚胺基]乙基]吡啶}合钴(II)（6）。晶体结构分析表明：配体5作为三齿配体以[N, N, O]原子和两个氯离子与中心钴(II)配位，形成畸变的三角双锥配位环境，其中吡啶氮原子和两个氯原子形成赤道平面。将该钴配合物作为催化剂应用于乙烯的聚合过程，以MAO为助催化剂，在15.5ºC下作用1 h，可达到1.820×10⁴ g/mol-Co∙h∙atm的催化活性。     

Mo／La－Co－O催化剂上甲烷选择氧化制甲醇反应

 制备了一系列Mo／La－Co－O催化剂，考察了催化剂对甲烷选择氧化制甲醇反应的催化性能，并用BET，XRD，LRS，H2－TPR和XPS等技术研究了催化剂的结构和性质．结果表明，在n（CH4）∶n（O2）∶n（N2）＝10∶1∶1，SV＝14．4L／（g·h），p＝4．2MPa和θ＝420℃的反应条件下，7％Mo／La－Co－O催化剂表现出较好的催化性能，甲醇选择性为60％，甲醇收率为6．7％．Mo负载于La－Co－O上以后，Mo－O物种以无定形的状态存在于La－Co－O表面，并与La－Co－O发生相互作用．Mo的负载量影响Mo－O物种的结构及催化剂的性质．催化剂的还原性和表面O－／O2－比影响催化剂上甲烷选择氧化制甲醇反应的性能．     

双（呋喃甲醛）缩二胺钴（II）配合物的合成及其氧合和催化氧化性能研究

合成和表征了氯化双（呋喃甲醛）缩邻苯二胺合钴（II）（1）、氯化双（呋 喃甲醛）缩乙二胺合钴（II）（2）、氯化双（呋喃甲醛）缩1,2-丙二胺合钴（ II）（3）和氯化双（呋喃甲醛）缩1,3-丙二胺合钴（II）（4）。在吡啶溶液中 和不同温度下,测定了配合物的饱和吸氧量,求出了氧加合常数和热力学参数ΔH °,ΔS°。并以这些配合物为催化剂,活化分子氧氧化环已烯得到高选择性的烯 丙位氧化产物。讨论了温度、配体结构对配合物氧合性能的影响和配体结构以及添 加NHPI（N-羟基邻苯二甲酰亚胺）对环已烯氧化反应的影响。     

贵金属对钴基催化剂上肉桂醛选择加氢反应的影响

 研究了贵金属改性的Co／γ－Al2O3催化剂上的肉桂醛选择加氢反应．结果表明，通过Pt，Pd和Ru贵金属改性，提高了催化剂的活性，但只有Pt改性的催化剂具有较高的选择性．w（Pt）＜0．5％时，催化剂的活性随着Pt含量的增加呈直线升高，当w（Pt）＝0．5％时，催化剂活性可提高近5倍，但催化剂的选择性变化很小．XRD结果表明，催化剂经还原后，γ－Al2O3上的钴主要为α－Co0．TPR结果表明，Pt的加入提高了Co3O4的还原性能，且Pt含量越高，Co3O4的还原温度越低．XPS结果表明，Pt改性的催化剂样品，其Co3O4大部分被还原为Co0．由于Pt与Co具有协同效应，故Pt改性的Co／γ－Al2O3催化剂既具有较高的活性，又具有很高的选择性．     

4—乙烯基吡啶—镍（钴）及丙烯酰胺—镍（钴）的制备、结构、聚合及聚合物

制备了4－乙烯基吡啶－镍（钴）和丙烯酰胺－镍（钴）络合物并研究了它们的结构。在自由基引发剂的作用下，4－乙烯基吡啶－镍可进行溶液聚合，也可与苯乙烯共聚合，测定了单体的竞聚率。所得的聚（4－乙烯基吡啶－镍）及聚（4－乙烯基吡啶－钴）以NαBH4还原后可作为一些有机化合物的加氢催化剂。由IR及XPS分析说明在丙烯酰胺－镍 合物中，与镍离子发生了络合作用的是碳基上的氧原子。     

光促进温和条件下烯烃与二氧化碳的羰基化反应

羰基化反应是有机合成化学中常用的方法之一,但常规的羰基化反应大多要求高温(150～200℃)、高压(10～20 M Pa)或使用贵金属催化剂(如钌、铑、铱等),并且C₁源多用一氧化碳^[1].开发和利用CO₂这一丰富的C₁资源,并最大限度地降低其排放量具有挑战意义.但CO₂活化比较困难,在通常条件下难以转化成其它化学品^[2].在光促进下的羰基化反应可克服上述困难,使反应在温和条件及非贵金属催化下完成,同时可用CO₂代替CO作为C₁源,因此这是一个对环境友好的工艺^[3].本文报道烯烃在光促进常温常压和非贵金属钴配合物催化下与二氧化碳的羰基化反应,同时通过¹³CO₂和¹³CH₃OH同位素实验,对反应产物的结构进行了分析.     

光促进下环己烯与二氧化碳羰基化反应中副产物的气相色谱-质谱分析

应用气相色谱-质谱法（GC-MS）研究了光促进温和条件下环己烯与CO2羰基化反应中与丙酮有关的副产物,这有助于对反应进行深入的研究和优化。在光促进温和条件下环己烯与CO2进行羰基化反应的同时,环己烯也可以与反应体系中的CH3COCH3发生光化学反应,生成副产物。分别用CH3COCH3和CD3COCD3进行实验,对反应产物进行GC-MS分析,通过对不同反应情况下的MS图中同位素效应的比较,可以分析出副产物中是否有来自CH3COCH3中的—CH3。研究表明丙酮与底物环己烯之间生成了环氧丁烷衍生物、cyclo-C6H9-C(CH3)2OH和cyclo-C6H11-C(CH3)2OH等3种副产物。     

Photopromoted carbonylation of bromobenzene under ambient conditions

The photopromoted carbonylation of bromobenzene with carbon monoxide catalyzed by inexpensive commercially available cobalt salts[Co(OAc)_2,CoCl_2]was carried out under ambient conditions.The results revealed that methyl benzoate was produced in the presence of basic additives(CH_3ONa,NaOAc or(n-C_4H_9)_3N).The catalytic activity of Co(OAc)_2was higher than that of CoCl_2.Furthermore,the activity of the carbonylation was greatly improved by addition of acetophenone,e.g.both the yield and selectivity of t...     

光促进下N,N-二甲基甲酰胺作为一氧化碳源的烯烃氢酯化反应

 研究了光照下以N,N-二甲基甲酰胺(DMF)为一氧化碳源的烯烃氢酯化反应. 结果表明,在常温常压和光照射条件下DMF可以分解得到CO,新生成的CO在光促进下可以直接与CH3OH-DMF溶液中的底物1-辛烯在温和条件和非贵金属钴化合物(Co(OAc)2,CoCl2,Co(en)3Cl2和大环钴[Co(14)4,11-二烯-N4]I2)催化下进行氢酯化反应,反应中DMF既是溶剂,又是原料. H13CON(CH3)2同位素示踪实验证实了这一结果. 在反应体系中通入二氧化碳可以大大提高反应的转化率、产率及选择性. 13CO2同位素示踪实验表明,CO2并未参与产物的形成,其作用是中和DMF分解产生的HN(CH3)2,从而有利于DMF的光促分解.     

Reactions of lead cluster ions with acetone

Reactions of lead cluster cations and anions with acetone have been studied using a homemade reflectron time-of-flight mass spectrometer. Association with acetone to form Pb(k)(CH(3)COCH(3))(n)(+), high-energy pathway reactions forming Pb(k)CH(3)(+), and intraheterocluster reaction of Pb(k)(CH(3)COCH(3))(n+1)(+) to give Pb(k)CH(3)(CH(3)COCH(3))(n)(+) were the main reaction pathways for lead cluster cations with acetone. Decomposition of acetone by Pb(k)(-) to give Pb(k)C(m)(-) ions and their further association with acetone, Pb(k)C(m)(CH(3)COCH(3))(-), were the dominant reactions of lead cluster anions with acetone. Pb(7)(-), Pb(10)(-), and Pb(k)C(5)(-) were 'magic numbers' with special structural stabilityin Pb(k)(-) and Pb(k)C(m)(-), respectively. In addition, Pb(k)H(-), CH(2)COCH(3)(CH(3)COCH(3))(n)(-) and Pb(k)CH(2)COCH(3)(CH(3)COCH(3))(n)(-) were also observed in the reaction of lead cluster anions. Some reaction mechanisms are proposed for these reactions. To investigate the isotope effect for the reaction of lead cluster cations and anions with acetone and to verify the structural assignments of the observed ions, reactions of lead cluster cations and anions with deuterated acetone-d(6) were also performed.     

A vacuum ultraviolet photoionization mass spectrometric study of acetone

The photoionization and dissociative photoionization of acetone have been studied at the photon energy range of 8-20 eV. Photoionization efficiency spectra for ions CH3COCH3+, CH3+, C2H3+, C3H3+, C3H5+, CH(2-)CO+, CH3CO+, C3H4O+, and CH3COCH2+ have been measured. In addition, the energetics of the dissociative photoionization has been examined by ab initio Gaussian-3 (G3) calculations. The computational results are useful in establishing the dissociation channels near the ionization thresholds. With the help of G3 results, the dissociation channels for the formation of the fragment ions CH3CO+, CH2CO+, CH3+, C3H3+, and CH3COCH2+ have been established. The G3 results are in fair to excellent agreement with the experimental data.     

Exchange of organic radicals with organo-cobalt complexes formed in the living radical polymerization of vinyl acetate

Exchange of organic radicals between solution and organo-cobalt complexes is experimentally observed and the reaction pathway is probed through DFT calculations. Cyanoisopropyl radicals from AIBN (2,2'-azobisisobutyronitrile) enter solutions of cobalt(II) tetramesityl porphyrin ((TMP)Co(II)*, 1) and vinyl acetate (VAc) in benzene and react to produce transient hydride (TMP)Co-H and radicals (*CH(OAc)CH2C(CH3)2CN (R1*)) that proceed on to form organo-cobalt complexes (TMP)Co-CH(OAc)CH3 (4, Co-R2) and (TMP)Co-CH(OAc)CH2C(CH3)2CN (3, Co-R1), respectively. Rate constants for cyanoisopropyl radical addition with vinyl acetate and hydrogen atom transfer to (TMP)Co(II)* are reported through kinetic studies for the formation and transformation of organo-cobalt species in this system. Rate constants for near-degenerate exchanges of radicals in solution with organo-cobalt complexes are deduced from (1)H NMR studies and kinetic modeling. DFT computations revealed formation of an unsymmetrical adduct of (TMP)Co-CH(OAc)CH3 (4) with *CH(OAc)CH3 (R2*) and support an associative pathway for radical interchange through a three-centered three-electron transition state [R...Co...R]. Associative radical interchange of the latent radical groups in organo-cobalt porphyrin complexes with freely diffusing radicals in solution that is observed in this system provides a pathway for mediation of living radical polymerization of vinyl acetate.     

The carbonylation of phenyl bromide and its derivatives under visible light irradiation

The carbonylation of phenyl bromide catalyzed by Co（OAc）₂ has been investigated with PhCOPh as a sensitizer under visible light in the presence of basic additive.With strong base CH₃ONa,PhCOOCH₃ is produced in 70%yield with 100%selectivity,the similar results are also obtained with a stronger base（CH₃）₃CONa.However,with another strong base NaOH,the yield of the ester is only 40%.On the other hand,with weak base NaOAc or（n-C₄H₉）₃N,phenyl bromide cannot be carbonylated.The results of carbonylation of the six substituted phenyl bromides suggest that the activities of o,m,p-BrC₆H₄CH₃ are similar to phenyl bromide, while the activities of o,m,p-BrC₆H₄Cl are higher with the high yields（≥93%） of the corresponding chloro-esters.In addition,the relative position of bromine and chlorine or methyl on phenyl ring has little effect on the activity of the carbonylation.     

Cobalt-catalyzed Photochemical Methoxycarbonylation of Olefins with Carbon Dioxide under Ambient Conditions

The methoxycarbonylations of cyclohexene and 1-decene with CO2 can take place under ambient conditions by catalysis of [Co]([Co]=Co(acac)2, Co(OAc)2, CoCl2 ) in the presence of ultraviolet irradiation.     

Cobalt-catalyzed photopromoted carbonylation of chloroalkanes in the presence of KI

<正>The photopromoted carbonylation of chloroalkanes with carbon monoxide catalyzed by cobalt compounds[Co(OAc)_2,CoCl_2] in the presence of KI was carried out under ambient conditions.The results revealed that the catalytic activity of Co(OAc)_2 was higher than that of CoCl_2.A basic additive NaOAc was beneficial to the reaction.Interestingly,with NaOAc as an additive, Co(OAc)_2 and CoCl_2 exhibited similar catalytic activity.Preliminary work showed that the role of iodide ion was initially to form active iodoalkanes via substituting chloride ion in chloroalkanes in situ,and then,the carbonylation of iodoalkanes proceeded under irradiation.