DIRECT CONVERSION OF SILYL ETHERS OR TETRAHYDROPYRANYL ETHERS INTO THE CORRESPONDING DIPHENYLMETHYL ETHERS

Direct conversion of alcohol silyl ethers into the corresponding diphenylmethyl (DPM) ethers can be easily performed by the reaction with diphenylmethyl formate in the presence of a catalytic amount of trimethylsilyl trifluoromethanesulfonate. By the additional use of triethylsilane, tetrahydropyranyl ethers can be also converted into the corresponding DPM ethers.     

EFFICIENT CONVERSION OF TETRAHYDROPYRANYL (THP) ETHERS TO THEIR CORRESPONDING CYANIDES WITH TRIPHENYLPHOSPHINE/2,3-DICHLORO- 5,6-DICYANOBENZOQUINONE/n-Bu4 NCN

Tetrahydropyranyl ethers were converted to their corresponding alkyl cyanides efficiently by using the triphenylphosphine/ 2,3-dichloro-5,6-dicyanobenoquinone/n-Bu ₄ NCN system in refluxing acetonitrile with good-to-excellent yields.     

SILICA ACETATE COMPLEX OF N2O4: A HIGHLY EFFICIENT REAGENT FOR THE SELECTIVE CONVERSION OF THIOETHERS TO THEIR CORRESPONDING SULFOXIDES

Complexation of gaseous N₂O₄ with acylated silica gel affords a molecular addition compound, which is a highly efficient oxidizing agent for the conversion of thioethers to sulfoxides.     

3,6-BIS(TRIPHENYLPHOSPHONIUM) CYCLOHEXENE PEROXODISULFATE AS AN EFFICIENT AND MILD OXIDIZING AGENT FOR CONVERSION OF ALKYLBENZENES TO CORRESPONDING CARBONYL COMPOUNDS

ABSTRACT

Oxidation of a series of alkylbenzenes by BTPCP under neutral conditions to corresponding carbonyl compounds is described.     

OXIDATIVE DEPROTECTION OF TRIMETHYLSILYL ETHERS TO CARBONYL COMPOUNDS WITH PdCI2(PhCN)2-CrO3 AND CLAY-BIS(TRIMETHYLSILYL) CHROMATE IN SOLVENTLESS SYSTEM

Abstract

A simple and selective oxidative deprotection of trimethylsilyl ethers to carbony1 compounds is described that occurs on PdCl₂(PhCN)₂-CrO₃ and bis(trimethylsily1) chromate under solvent free conditions and is expedited by microwave irradiation.     

CARO'S ACID SUPPORTED ON SILICA GEL,PART VIII: AN EFFICIENT AND SELECTIVE REAGENT FOR CONVERSION OF PHENYLHYDRAZONES AND SEMICARBAZONES TO THE CORRESPONDING CARBONYL COMPOUNDS

Deprotection of phenylhydrazones and semicarbazones to their parent aldehydes and ketones in high yields has been carried out using caro's acid supported on silica gel as a selective oxidant under mild conditions.     

氧电极催化剂Ln1-xSrxMO3及其在锌/空气电池中的应用

稀土(Ln)和过渡元素M(Co,Ni或Mn)复合氧化物Ln_1-xSr_xMO₃(x=0.1～0.5)与活性炭混合后,对氧阴极还原有较好的催化性能。用Ln_1-xSr_xMO₃(10%)-活性炭与Ag(21.2%)-胶体石墨(39.4%)-活性炭为催化剂制成的空气阴极,在相同条件下进行常温、低温(-20—--40℃)和长期湿贮存对比实验表明,前者的性能都较后者为好。大量锌/空气电池实验表明,这样复合氧化物催化剂可以代替银作氧电极催化剂。单体电池比能量达到每公斤340W·h或每升430W·h,由此催化剂制得的锌/空气电池具有良好的湿搁置寿命。     

聚多缩乙二醇对苯二酚醚的合成及其色谱性能Ⅰ.

由对苯二酚与二氯甘醇反应合成了一系列聚多缩乙二醇对苯二酚醚,M=2800～4500。这些聚醚是一类高效、广谱性气相色谱固定液,可用于有机混合物的有效分离鉴定。     

SILICA PHOSPHORIC ACID/NaNO2 AS A NOVEL HETEROGENEOUS SYSTEM FOR THE COUPLING OF THIOLS TO THEIR CORRESPONDING DISULFIDES

Silica phosphoric acid was prepared via reaction of silica chloride (I) and phosphoric acid. Thiols can be readily converted to their corresponding thionitrites with a combination of silica phosphoric acid (II), wet SiO ₂ , and sodium nitrite in dichloromethane at room temperature. Disulfides result from the homolytic cleavage of the sulfur–nitrogen bond of the unstable thionitrite and subsequent coupling of the resultant thiyl radicals.     

N-BROMOBIS(P-TOLUENESULFONYL)AMINE AS A NOVEL AND MILD REAGENT FOR CONVERSION OF OXIMES TO CARBONYL COMPOUND

N-Bromobis(p-toluenesulfonyl)amine (NBBTA) is a novel and efficient reagent for the conversion of oximes to their corresponding carbonyl compounds in good yields under mild conditions.     

中孔分子筛的合成及作为FT合成催化剂载体的应用

分别用季铵盐和中性一级胺为模板剂，在水热条件下和常温常压下合成了纯Ｓｉ和含Ａｌ的中孔分子筛；用ＢＥＴ，ＸＲＤ，ＳＥＭ等手段表征了它们的孔道和骨架结构，对中孔分子筛的生成机理进行了探讨。研究发现，不同的介质，不同的模板剂以及不同的硅、铝源都可以影响产物的最终结构和稳定性。在碱性介质中用季胺盐作模板剂，用无机硅源的条件下，水热过程是形成中孔分子筛稳定晶格的必要条件。室温条件下合成中孔分子筛，体系的静电作用增强有利于产物结构的稳定。另外，本文以各种中孔分子筛作为催化剂载体担载ＺｒＯ２对ＣＯ加氢反应进行了初步研究，就产物的分布情况和ＺｒＯ２／ＺＳＭ５，ＺｒＯ２／β沸石，ＺｒＯ２／ＨＹ上作了对比。结果表明用中孔分子筛作载体的催化剂和小孔分子筛系列相比对Ｃ＝２～Ｃ＝４有较高的选择性。     

环戊烷选择性氧化用VPO催化剂的合成新方法

研究了ＶＰＯ催化剂时还原溶剂对ＶＰＯ的结构及催化性能的影响,ＶＰＯ的合成方法如下：（１）Ｖ２Ｏ５与Ｈ３ＰＯ４反应生成磷酸钒;（２）用不同的还原溶剂还原磷酸钒得到ＶＰＯ催化剂前身;（３）活化ＶＰＯ催化剂前身,研究的还原溶剂有;异丁醇,异丁醇－苯甲醇,异丁醇－石油醚和正己醇。结果表明,使用异丁醇－石油醚作还原溶剂,只能生成ＶＯＨＰＯ４．０．５Ｈ２Ｏ晶体;使用其它溶剂则会生成ＶＯ（Ｈ２ＰＯ４）２和ＶＯＨ     

苯基重氮盐-冠醚分子嵌合物的FAB-MS及其准分子离子生成机理的研究

苯基重氮盐质谱研究曾有报导,它同冠醚分子形成的嵌合物质谱也被测定过。本文采用快原子轰击(FAB)研究了苯基重氮盐,(R=OCH_3,CH_3,H,Br,Cl,F,NO_2)同18-冠醚-6以及二苯并-24-冠醚-8形成分子嵌合物的质谱(MS),讨论这类嵌合物准分子离子MNa~ 丰度同嵌合物内授-受键的性质之间的关系,并由分子轨道方法计算结果解释了MNa~ 的丰度同苯基重氮盐上取代基R性质的关系。     

PHOSPHORUS PENTASULFIDE AS A MILD,SELECTIVE REAGENT FOR THE REDUCTION OF SULFOXIDES TO SULFIDES

Abstract

It has been shown that phosphorus pentasulfide (P₄S₁₀) is a mild, effective reagent for the reduction of sulfoxides to sulfides and that this conversion can be achieved selectively in the presence of other reactive groups such as ketone, ester, amide, nitro and halogen. This reagent can be used in similar fashion for the efficient reduction of sulfilimines (in both the N-p-toluenesulfonyl and free NH forms). Phosphorus pentasulfide also appears to be a promising reagent for reducing selenoxides but is ineffective in reducing sulfones, sulfinates, or sulfites. The mechanistic evidence presented indicates a probable four-centre (Wittig-like) intermediate or transition-state for the reduction by P₄S₁₀.     

纳米丝负载钯催化剂的制备及催化烯烃加氢性能研究

利用电纺丝技术制备出苯乙烯-丙烯腈共聚物负载钯的纳米丝催化剂.对催化剂进行了SEM、TEM、IR和XPS的测试.所制备的催化剂对α-己烯催化氢化结果表明,该催化剂在常温、氢气常压下具有很高的催化活性和较好的重复使用性,并且催化氢化过程中存在烯烃的异构化反应.实验结果表明,反应时间为150min时纳米催化剂A对α-己烯催化加氢生成正己烷的转化率是传统催化剂PdCl2/-γAl2O3的4.7倍.     

DICHLORO (5,10,15,20-TETRAPHENYLPORPHYRIN) PHOSPHORUS(V) CHLORIDE AS A NEW CATALYST FOR CONVERSION OF 1,2-EPOXYETHANES TO 2-HYDROXYETHYL THIOCYANATES WITH AMMONIUM THIOCYANATE

A convenient and efficient procedure for the cleavage of the oxirane rings with ammonium thiocyanate in the presence of phosphorus(V)tetraphenylporphyrin is described. The ring-opening of 1,2- epoxyethanes is found to proceed regioselectively under mild reaction conditions. Thus, several 2-hydroxyethyl thiocyanates, useful intermediates toward biologically active molecules, are easily obtained in very good yields.     

对叔丁基甲苯选择性氧化制对叔丁基苯甲醛催化剂研究--助剂T1的添加对催化剂结构及反应性能的影响

对叔丁基苯甲醛是香精香料及其它食用化工行业的重要原料 ,采用对叔丁基甲苯气相选择性氧化制对叔丁基苯甲醛可以克服对叔丁基苯甲醛生产过程中设备腐蚀严重、污染环境、工艺落后繁琐等缺点 ,所以一直是广大科技工作者十分关注的研究课题。迄今为止 ,国内外学者已有不少关于甲苯气相选择性氧化制苯甲醛的报道[1～ 3] ,但关于对叔丁基甲苯选择性氧化制对叔丁基苯甲醛的研究几乎未见报道。本文考察了在Ｖ -Ｃｓ -Ｃｕ体系催化剂上引入助剂Ｔ1后对催化剂反应性能的影响 ,结果发现助剂Ｔ1的添加对于提高对叔丁基苯甲醛的选择性具有明显的促进作…     

正丁烷氧化制顺酐磷—钒催化剂的制备和活化

用XRD、IR、XPS和ESR等方法,考察了以草酸、盐酸羟氨、盐酸联氨和异丁醇分别作还原剂制备的磷-钒催化剂在不同条件下活化及用于正丁烷氧化制顺酐反应后的相组成和催化剂的性能。实验结果表明,影响顺酐收率的主要因素是催化剂的相组成及钒的氧化态,而不是催化剂的比表面积。在催化剂制备过程中,所用还原剂的种类以及活化条件对催化剂的性能都有重要影响。     

ZEOLITE-SUPPORTED CHROMIUM(VI) OXIDE: A MILD,EFFICIENT, AND INEXPENSIVE REAGENT FOR OXIDATIVE DEPROTECTION OF TRIMETHYLSILYL ETHERS UNDER MICROWAVE IRRADIATION

Primary and secondary trimethylsilyl ethers are effeciently converted to the corresponding carbonyl compounds using HZSM-5 zeolite-supported CrO ₃ under microwave irradiation in solventless system.