Acetalation and Ketalation Catalyzed by SO42-/TiO2-MoO3

The catalytic activities of SO42-/TiO2-MoO3 in synthesizing cyclohexanone ethylene ketal,cyclohexanone 1,2-propanediol ketal, 2-propyl-1,3-dioxolane, 4-methyl-2-isopropyl-1,3-dioxolane,2-isopropyl-1,3-dioxolane, 4-methyl-2-isopropyl-1,3-dioxolane, butanone ethy-lene ketal and butanone 1,2-propanediol ketal were reported. It has been demonstrated that SO42-/TiO2-MoO3 is an excellent catalyst. Various factors concerned in this reaction have been investigated. The optimum conditions have been found, that is, the molar ratio of aldehyde/ketone to alcohol was 1:1.5 or 1:1.3,the mass ratio of the catalyst used to the reactants was 0.25～1.5%, and the reaction time was 45～60 min. Under this conditions, the yield of cyclohexanone ethylene ketal is 82.7%, cyclohexanone 1,2-propanediol ketal is 83.4%, the yield of 2-propyl-1,3-dioxolane is 68.1%,4-methyl-2-isopropyl-1,3-dioxolane is 87.5%, the yield of 2-isopropyl-1,3-dioxolane is 70.7%,4-methyl-2-isopropyl-1,3-dioxolane is 82.5%, the yield of butanone ethylene ketal is 74.1%, and butanone 1,2-propanediol ketal is 94.9%.Some equation and experiment results concerned of the synthetic acetals or ketals were listed as follows.     

Preparation and Catalytic Activity of PW_(12)/PAn Material in Synthesis of 2-Methyl-2-Ethyl Acetoacetate-1,3-Dioxolane

Acetals and ketals are among the most important perfume materials and industrial materials of organic synthesis. Up to now, there are many methods to synthesize them. Conventionally H2SO4 is used as catalyst in factories, but it causes many problems, such as the erosion of equipment, difficulty for after-treatment, low quality of the products, etc. Heteropolyacids (HPA) and their salts have been extensively studied because of their interesting catalytic properties. Significant research effo…     

Oxidation of 1,3-Dioxacyclanes with Oxone and Potassium Persulfate Catalyzed by 2,2,5,5-Tetramethyl-4-Phenyl-3-Imidazoline-3-Oxide-1-Oxyl

The catalytic effect of 2,2,5,5-tetramethyl-4-phenyl-3-imidazoline-3-oxide-1-oxyl on the oxidation of 2-isopropyl-1,3-dioxolane, 2-phenyl-1,3-dioxolane, 2-phenyl-4-chlormethyl-1,3-dioxolane, 2-isopropyl-1,3-dioxane, 2-isopropyl-4-methyl-1,3-dioxane, 2-phenyl-1,3-dioxane, 2-phenyl-4-methyl-1,3-dioxane with oxone and potassium persulfate is reported. The corresponding glycol monoesters were obtained with yields of 90-100%.     

固载杂多酸盐催化剂的制备与性能研究

介绍了固载型杂多酸盐催化剂TiSiW12 O4 0 /TiO2 的两种制备方法 ,并以乙酸正丁酯的合成 ,考察了制备条件对其催化活性的影响 ,结果令人满意     

Synthesis of 1-Bromo-3-butyn-2-one and 1,3-Dibromo-3-buten-2-one

Synthetic procedures for the preparation of 1-bromo-3-butyn-2-one and 1,3-dibromo-3-buten-2-one are given. These compounds are prepared from 2-bromomethyl-2-vinyl-1,3-dioxolane, which can readily be prepared from 2-ethyl- 2-methyl-1,3-dioxolane. The synthetic routes are as follows: 2-bromomethyl-2-vinyl-1,3-dioxolane is converted to 2-(1,2-dibromoethyl)-2-bromomethyl-1,3-dioxolane. Double dehydrobromination with ^tBuOK affords 2-ethynyl-2-bromomethyl-1,3-dioxolane. Formolysis with formic acid gives 1-bromo-3-butyn-2-one. Deacetalized 2-bromoethyl-2-vinyl-1,3-dioxolane was treated with Br₂ and Li₂CO₃/12-crown-4 in tetrahydrofuran to give 1,3-dibrom-3-buten-2-one in moderate yield.     

固载杂多酸盐催化合成苯甲酸正戊酯

首次报道了以固载杂多酸盐TiSiW12 O4 0 /TiO2 为多相催化剂 ,对以苯甲酸和正戊醇为原料合成苯甲酸正戊酯的反应条件进行了研究 .实验表明 :TiSiW12 O4 0 /TiO2 是合成苯甲酸正戊酯的良好催化剂 .最佳反应条件为 :醇酸物质量比为 4∶1,催化剂用量为反应物料总量的 1.5 % ,反应时间为 2 .5h .上述条件下 ,苯甲酸正戊酯的产率可达 96 .7% .     

二氧化硅负载硅钨钼酸催化合成环己酮1,2-丙二醇缩酮

采用溶胶-凝胶法制备了二氧化硅负载硅钨钼酸催化剂。以二氧化硅负载硅钨钼酸为催化剂,环己酮和1,2-丙二醇为原料合成了环己酮1,2-丙二醇缩酮,用正交实验法研究了反应物料配比、催化剂用量、带水剂用量、反应时间等因素对反应的影响。结果表明,在n(环己酮)∶n(1,2-丙二醇)=1∶1.4,催化剂用量为反应物料总质量的0.8%,带水剂环己烷12 mL,反应时间45 min的优化条件下,环己酮1,2-丙二醇缩酮的收率可达84.93%。     

新型树形化合物1,3,5-三-[7-(7-甲基-2,2-二-(2,2-二羟甲基-3-羟基丙氧基羰基)-6,8-二氧杂螺[3.5]-壬基)]苯的合成

以丙酮和甲酸乙酯为原料, 在醇钠的作用下合成了1,3,5-三乙酰基苯(1). 1与二溴新戊二醇在酸的作用下发生缩酮化反应, 制成1,3,5-三-(1-甲基-2,6-二氧杂-4,4-二溴甲基环己基)苯(2). 2与5,5-二甲基-4,6-二氧杂-1,3-环己二酮在乙醇钠的作用下合成了1,3,5-三-[7-(7-甲基-2,2-二-乙氧羰基-6,8-二氧杂螺[3.5]-壬基)]苯(3). 将3在氯仿中与季戊四醇进行酯交换反应得到产物1,3,5-三-[7-(7-甲基-2,2-二-(2,2-二羟甲基-3-羟基丙氧基羰基)-6,8-二氧杂螺[3.5]-壬基)]苯(4). 收率为47.7%. 标题化合物及中间产物使用IR, ¹H NMR和MS或元素分析进行了表征.     

Relative reactivities of cyclic ketene acetals via cationic 1,2-vinyl addition copolymerization1

The relationship between the relative reactivities of ten cyclic ketene acetals and their structures was determined via cationic copolymerizations of eight different monomer pairs. Thus, 2-methylene-1,3-dioxolane (1) was copolymerized with 2-methylene-4-methyl-1,3-dioxolane (2), 2-methylene-4,5-dimethyl-1,3-dioxolane (3), 2-methylene-4,4,5,5-tetramethyl-1,3-dioxolane (4), 2-methylene-4-phenyl-1,3-dioxolane (5), and 2-methylene-4-(t-butyl)-1,3-dioxolane (6). Also 2-methylene-1,3-dioxane (7) was copolymerized with 2-methylene-4-methyl-1,3-dioxane (8), 2-methylene-4,4,6-trimethyl-1,3-dioxane (9), and 2-methylene-4-isopropyl-5,5-dimethyl-1,3-dioxane (10). The relative reactivities of these monomers are: 3 > 5 > 4 > 2 > 1 > 6; and 10 > 9 > 8 > 7. In spite of steric demands, substituents at the 4- or 5-positions in 2-methylene-1,3-dioxolane and substituents at the 4- or 6-positions in 2-methylene-1,3-dioxane serve to increase the copolymerization reactivity. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 2841–2852, 1999     

Cationic polymerizations of substituted 2-methylene-1,3-dioxocyclic acetals, 2-methylene-1,3-dithiolane and copolymerization of 2-methylene-1,3-dithiolane with 4-(t-butyl)-2-methylene-1,3-dioxolane1

Carbon black-supported sulfuric acid or BF₃·Et₂O-initiated polymerizations of 2-methylene-4,4,5,5-tetramethyl-1,3-dioxolane (1), 2-methylene-4-phenyl-1,3-dioxolane (2), and 2-methylene-4-isopropyl-5,5-dimethyl-1,3-dioxane (3) were performed. 1,2-Vinyl addition homopolymers of 1–3 were produced using carbon black-supported H₂SO₄ initiation at temperatures from 0°C to 60°C whereas both ring-opened and 1,2-vinyl structural units were present in the polymers using BF₃·Et₂O as an initiator. Cationic polymerizations of 2-methylene-1,3-dithiolane (4) and copolymerization of 4 with 2-methylene-4-(t-butyl)-1,3-dioxolane (5) were initiated with either carbon black-sulfuric acid or BF₃·Et₂O. Insoluble 1,2-vinyl addition homopolymers of 4 were obtained upon initiation with the supported acid or BF₃·Et₂O. A soluble copolymer of 2-methylene-1,3-dithiolane (4) and 4-(t-butyl)-2-methylene-1,3-dioxolane (5) was obtained upon BF₃·Et₂O initiation. This copolymer is composed of three structural units: a ring-opened dithioester unit, a 1,2-vinyl-polymerized 1,3-dithiolane unit, and a 1,2-vinyl polymerized 4-(t-butyl)-1,3-dioxolane unit. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 2823–2840, 1999     

The chameleon-like nature of zwitterionic micelles. Control of anion and cation binding in sulfobetaine micelles. Effects on acid equilibria and rates

The rate of specific hydrogen ion catalyzed hydrolysis of 2-(p-heptoxyphenyl)-1,3-dioxolane and equilibrium protonation of 1-hydroxy-2-naphthoate ion in zwitterionic micelles of SB3-14, C14H29NMe2+(CH2)3SO3-, are increased markedly by NaClO4 which induces anionic character and uptake of H3O+ in the micelles. Other salts, for example, NaNO3, NaBr, and NaCl, have similar but much smaller effects on this uptake of H3O+.     

First aminoacetone chelate: [Co(tren){NH2CH2C(O)CH3}]3+-a substrate binding and activation model for zinc(II)-dependent 5-aminolaevulinic acid dehydratase

The complex p-[Co(tren){NH(2)CH(2)C(O)CH(3)}](ClO(4))(3).H(2)O was produced stereoselectively from [Co(tren)(O(3)SCF(3))(2)]O(3)SCF(3) () and 2-(aminomethyl)-2-methyl-1,3-dioxolane. The structure of was determined by X-ray crystallography. The complex is the first aminoacetone chelate to be reported and the first structurally characterized example of a non-conjugated ketone moiety coordinated to cobalt(iii). The robust complex was stable to aquation in strong acid and behaved as an acid with pK(a) = 4.99(1) indicative of a strong activation of the aminoacetone ligand towards deprotonation. The complex constitutes a structural model for a proposed substrate binding mode relevant for substrate activation of the zinc(ii)-dependent enzyme 5-aminolaevulinic acid dehydratase.     

Syntheses, derivatives, solubility, and interfacial properties of 2-methyl-2-polyfluoroalkenyloxymethyl-1,3-propanediols: potential building blocks for syntheses of amphiphatic macromolecules

2-Hydroxymethyl-2-methyl-1,3-propanediol (A) was reacted with (Me(3)Si)(2)NH and toluenesulfonyl chloride (TsCl) to give mainly CH(3)C(CH(2)OSiMe(3))(3) (1), and CH(3)C(CH(2)OTs)(3) (2), respectively. With allyl bromide, the products were CH(3)C(CH(2)OCH(2)CH[double bond]CH(2))(2)(CH(2)OH) (3) and CH(3)C(CH(2)OCH(2)CH[double bond]CH(2))(CH(2)OH)(2) x H(2)O (4). The reactions of 4 with perfluoroalkyl iodides (R(f)I) were catalyzed by Cu(I)Cl to form 2-methyl-2-polyfluoroalkenyloxymethyl-1,3-propanediols: (R(f)CH=CHCH(2)OCH(2))C(Me)(CH(2)OH)(2) [R(f) = C(4)F(9) (5), C(8)F(17) (6), and (CF(2)CF(2))(4)OCF(CF(3))(2) (7)]. Reduction of 5 and 6 with hydrogen gave two new 2-methyl-2-polyfluoroalkyloxymethyl-1,3-propanediols, 8 and 9. The sodium salt of 9 was reacted with allyl bromide or acetyl chloride to form (C(8)F(17)CH(2)CH(2)CH(2)OCH(2))C(Me)(CH(2)OX)(CH(2)OH)(2) [where X = CH(2)CH=CH(2) (10) or C(O)CH(3) (12)] and (C(8)F(17)CH(2)CH(2)CH(2)OCH(2))C(Me)(CH(2)OX)(2) [where X = CH(2)CH[double bond]CH(2) (11) or C(O)CH(3) (13)]. Reaction of tolenesulfonyl chloride with 7 gave the monotosylate, 14, as the sole product. With 4-trifluoromethylbenzyl bromide, the sodium salt of 4 gave (4-CF(3)C(6)H(4)CH(2)OCH(2))C(Me)(CH(2)CH[double bond]CH(2))(CH(2)OH) x H(2)O (15). The compounds were characterized by NMR ((1)H, (13)C, (19)F, (29)Si), GC-MS, and high-resolution MS or elemental analyses. UV evidence was obtained for partitioning of 9, 12, 14, and 15 between perfluorodecalin and n-octanol. The test compounds acted as surfactants by facilitating the solubility of phenol and Si(CH[double bond]CH(2))(4) in perfluorodecalin. The single-crystal X-ray structure of 8 was also obtained. It crystallized in the monoclinic space group P2(1)/c, and unit cell dimensions were a = 24.966(2) A (alpha = 90), b = 6.1371(6) A (beta = 100.730(2)), and c = 10.5669(10) A (gamma = 90).     

CuOx/TiO2光催化水蒸气还原CO2

以商品TiO2-P25为原料,通过浸渍法负载一定量过渡金属Cu,得到一系列不同含量的CuOx/TiO2光催化剂。利用X射线衍射（XRD）,X－射线光电子能谱（XPS）,BET,高分辨率透射镜（HRTEM）,X射线荧光光谱（XRF）和光致发光光谱（PL）等方法对催化剂进行了详细表征,在自建的光催化反应器中评价了气态水光催化还原CO2反应的活性和CH4收率。结果表明负载CuOx后的TiO2纳米材料光催化性能显著提高,其中1%CuOx/TiO2样品紫外光照72 h后,CH4生成量达到了24.86 µmol•gTi-1。同时,CuOx负载量、反应温度、反应时间等因素对CH4收率均有显著影响。     

Si取代Keggin型多酸催化光解水产氢机理

本文采用DFT和TD-DFT方法研究了Keggin型多酸[SiW12O40]4-光催化劈裂水产氢气机理。计算结果显示反应主要包括四个步骤：(i) 光激发,(ii) 电荷转移和生成单电子还原(OER)中间体,(iii) 生成双电子还原(TER)中间体,(iv)氢气从多酸表面解离和催化剂重生。当第一个电子从甲醇转移到多酸后,后续反应存在均为热力学上有利的放热途径,并推动第二个电子从甲醇自由基,H[SiW12O40]4-或[SiW12O40]5-转移到OER中间体H[SiW12O40]4-或[SiW12O40]5-生成TER中间体[SiW12O40]6-,H[SiW12O40]5-或H2[SiW12O40]4-,并伴随着H2产生。耦合的电子和质子转移路径在能量上最有利。甲醇和水分子的参与有利于H2产生。多酸在整个催化循环中,扮演了光敏剂、催化剂、电子的受体和给体。     

不同前驱体制备的Mn-H4SiW12O40/SiO2 催化剂对二甲醚催化氧化制取甲缩醛反应性能的影响

采用浸渍法分别用硫酸锰、醋酸锰、氯化锰和硝酸锰为原料制备了Mn-H4SiW12O40/SiO2 杂多酸催化剂。在常压连续流动固定床反应器中,考察了二甲醚选择氧化制取甲缩醛的反应活性。实验结果表明,催化剂的催化活性顺序为Mn-Cl2H4SiW12O40/SiO2>Mn(NO3)2H4SiW12O40/SiO2>MnSO4H4SiW12O40/SiO2>Mn(AC)2H4SiW12O40/SiO2。并进一步考察了反应温度对不同锰盐前驱体催化剂性能的影响。结果表明,随温度的升高,硫酸锰修饰的H4SiW12O40/SiO2 催化剂催化氧化比较剧烈,在613K时二甲醚转化率高达42.4%,但此时甲缩醛选择性仅为0.9%。采用氯化锰修饰的H4SiW12O40/SiO2催化剂,二甲醚催化氧化反应较缓和,并且甲缩醛的选择性明显高于分别采用硫酸锰、醋酸锰和硝酸锰改性的催化剂,在593K反应1h时,二甲醚转化率为8.6%,甲缩醛选择性达到37.5%。H2-TPR结果显示,硫酸锰改性的催化剂高温氧化性能明显强于另外三种催化剂,氯化锰的修饰使得催化剂的低温氧化性能变强。XRD结果表明,MnCl2 H4SiW12O40/SiO2催化剂的衍射特征峰明显强于其他三种催化剂,并且发现了MnO2衍射特征峰。     

KF-Al2O3催化下2-氨基-6-甲基-4-芳基-1,3-二氰基苯衍生物的合成

以芳醛、丙二腈和丙酮为底物, 乙醇为溶剂, 在70 ℃以KF/Al2O3催化合成了一系列的2-氨基-6-甲基-4-芳基-1,3-二氰基苯衍生物, 产物的结构通过IR, 1H NMR和元素分析确证.     

Preparation and radical ring-opening polymerization of 2-substituted-4-methylene-1,3-dioxolanes

2-Methyl-2-phenyl-4-methylene-1,3-dioxolane ( IIa ), 2-ethyl-2-phenyl-4-methylene-1,3-dioxolane ( IIb ), 2-phenyl-2-(n-propyl)-4-methylene-1,3-dioxolane ( IIc ), 2-phenyl-2-(i-propyl)-4-methylene-1,3-dioxolane ( IId ), 2-(n-heptyl)-2-phenyl-4-methylene-1,3-dioxolane ( IIe ), 2-methyl-2-(2-naphthyl)-4-methylene-1,3-dioxolane ( IIf ), and 2,2-diphenyl-4-methylene-1,3-dioxolane ( IIg ) were prepared and polymerized in the presence of a radical initiator. IIa–IIf were found to undergo vinyl polymerization with ring-opening reaction accompanying the elimination of ketone groups in bulk. IIg was found to undergo the quantitative ring-opening reaction accompanying the elimination of benzophenone in solution to obtain polyketone without any side reaction.     

Oxidation of 1,3-Dioxacycloalkanes with Complexes of Potassium Chlorochromate and Chlorodiperoxochromate with 15-Crown-5, Catalyzed with 2,2,5,5-Tetramethyl- 4-phenyl-3-oxo-3λ5-imidazolin-1-yloxyl

2,2,5,5-Tetramethyl-4-phenyl-3-oxo-3⁵-imidazolin-1-yloxyl catalyzes oxidation of 2-isopropyl-1,3-dioxolane, 2-phenyl-1,3-dioxolane, 2-phenyl-4-chloromethyl-1,3-dioxolane, and 2-phenyl-1,3-dioxane with 15-crown-5 complexes of potassium chlorodiperoxochromate (KCrO₅Cl·2C₁₀H₂₀O₅) and potassium chlorochromate (KCrO₃Cl·2C₁₀H₂₀O₅). 2-Isopropyl-1,3-dioxolane is oxidized to the corresponding monoester in quantitative yield, and the 2-phenyl derivatives yield benzaldehyde. The spiro ketal, 2,2-pentamethylene-4-methyl-1,3-dioxane, is decomposed to cyclohexanone.     

孔道结构H3PW12O40/TiO2的制备及其可见光光催化降解水溶性染料的性能

 采用溶胶-凝胶方法制备了孔道结构复合材料H3PW12O40/TiO2,采用ICP-AES,UV/DRS,31P MAS NMR,TEM和N2吸附等技术对其组成和结构进行了表征. 结果表明,催化剂中活性组分H3PW12O40的基本骨架结构未发生改变,H3PW12O40的担载量为22.29%,催化剂平均粒径为40 nm,具有双孔结构,其平均微孔和介孔孔径分别为0.61和3.06 nm. 考察了催化剂可见光光催化降解6种水溶性染料的性能. 结果表明,6种染料均可不同程度地被降解和矿化. 通过对染料中性红的光催化降解实验,比较了H3PW12O40/TiO2,Degussa P-25和锐钛矿结构TiO2的可见光光催化活性,其中,H3PW12O40/TiO2活性最高,且催化剂最易分离,可循环使用.