固体超强酸ZrO_2/SO_4~(2-)催化合成水杨酸甲酯

研究了以ZrO2 /SO2 - 4固体超强酸催化水杨酸与甲醇合成水杨酸甲酯的反应。在沸腾条件下连续滴加甲醇 ,控制甲醇的滴加速度与甲醇的馏出速度相等 ,反应 6h ,水杨酸的转化率达81 6%。     

固体超强酸ZrO2/SO2-4催化合成水杨酸甲酯

研究了以ZrO2/SO2-4固体超强酸催化水杨酸与甲醇合成水杨酸甲酯的反应.在沸腾条件下连续滴加甲醇,控制甲醇的滴加速度与甲醇的馏出速度相等,反应6 h,水杨酸的转化率达81.6%.     

4,4-二甲氧基-2-丁酮的合成研究

以金属钠为原料,甲醇为溶剂,先制成甲醇钠的饱和甲醇溶液,再滴加丙酮和甲酸甲酯进行Claisen酯缩合制得丁酮烯醇钠,最后在强酸作用下与甲醇进行缩醛化反应合成了4,4-二甲氧基-2-丁酮,过程总收率达到73.1%,纯度98.7%。产品通过IR和MS进行了表征。考察了原料的用量、反应温度,反应时间、滴加速度、反应体系pH值等方面对反应收率的影响,并得出了最适宜的工艺条件。     

CuI与2,2,6,6四-甲基氮氧自由基催化H2O2氧化醇类

开发了一种使用清洁氧化剂H2O2,以CuI与2,2,6,6-四甲基氮氧自由基（简称TEMPO）共催化氧化醇类合成醛酮香料化合物的方法。以苯甲醇催化氧化合成苯甲醛为例,探讨各种条件对该类反应的影响和反应机理。得出在苯甲醇1.08g（10mmol）,CuI0.095g（0.5mmol）,TEMPO0.046g（0.3mmol）,CH2Cl210mL,室温搅拌下滴加H2O2（30%）20mmol,反应8h,经硅胶色谱柱分离,得到无色液体（苯甲醛）1.0g（94%）。产物结构经质谱和核磁表征确认。通过此例挖掘H2O2的氧化潜能,考察体系反应条件对转化率、选择性与产率的影响以及体系所适用的范围。     

5-溴-2-羟基-3-(1-丙酰基)苯甲酸甲酯合成工艺的研究

以水杨酸为原料合成5-溴-2-羟基3-(1-丙酰基)苯甲酸甲酯,从催化剂的用量、物料配比等方面研究了水杨酸甲酯化反应,以及从反应溶剂、加料方式和原料配比等方面研究了C-酰化反应,并利用IR、GC-MS确认产品结构。最佳工艺条件为:m(离子交换树脂催化剂):m(水杨酸)为1:100,n(甲醇):n(水杨酸)=7:1,氯仿为溶剂,加料方式为将酯滴加到氯化铝的氯仿溶液中,n(氯化铝):n(5-溴水杨酸甲酯):n(丙酸酐)=2:1:1,反应物总收率为74.52%。     

亚甲基二磺酸的合成工艺研究

以价廉易得的亚甲基二磺酸钠为起始原料,在甲醇溶剂中,以氯化亚砜为催化剂进行酯化反应。所得酯化产物经除杂、水解、浓缩、除水等操作获得高品质的亚甲基二磺酸。本文重点对此工艺的可行性及影响酯化反应的因素:温度、滴加速度和反应时间进行了考察,通过改变反应条件,确定最佳反应温度为0～40℃,滴加时间为4h,最佳反应时间为1h,酯化收率为94%,总收率为93.5%。     

固体超强酸ＳＯ４^2—／TiO2—Al2O3的制备及在合成水杨酸乙酯反应中的初步应用

本文主要研究了固体超强酸ＳO^2-4/TiO2-Al2O3的制备，及其在水杨酸与乙醇直接酯化法合成水杨酯反应中的应用，并考察了催化剂用量，反应时间，反应温度，醇酸比对酯化率的影响，得出如下结论，水杨酸用量为１０g(0.0724mol)的条件下固体超强酸ＳO^2-4/TiO2-Al2O3的用１g，醇酸摩尔比为１０：１，反应时间５h，反应温度７８－８０℃是最佳反应条件，酯产率为８４．６％。     

W/O型微乳液法制备纳米SiO2

选择适当的乳化剂和水解温度以及控制水与乳化剂的摩尔比,采用W/O型微乳液法在聚醚多元醇中通过正硅酸乙酯的水解、缩合反应合成了纳米SiO2.红外光谱法(FTIR)证明纳米SiO2粒子的生成,透射电子显微镜(TEM)显示合成的SiO2微粒呈球状且分散,粒径分布在50～70 nm.研究了反应时间、正硅酸乙酯用量、滴加速度及pH值对纳米SiO2制备的影响.通过实验得知,反应时间2 h左右,24 mL聚醚多元醇中正硅酸乙酯的用量0.9～3.6 mL,在10 min内滴加完毕能达到最佳反应效果.     

固体超强酸ZrO2-SO42-催化合成水杨酸异戊酯的研究

采用固体超强酸ZrO2-SO4^2-催化合成水杨酸异戊酯最佳反应条件为：n(异戊醇)：n(水杨酸)=10：1，反应温度130℃，反应时间4h，催化剂用量为水杨酸质量的1％，酯收率大于90％。     

2-巯基苯并噻唑氧化合成苯并噻唑

以2-巯基苯并噻唑为原料,用双氧水进行氧化合成苯并噻唑,从反应原料的含量、反应温度、氢氧化钠含量、酸化时间4个方面优化了合成工艺。结果表明,优化反应条件为:50 mmol双氧水滴加到溶解有25 mmol 2-巯基苯并噻唑的100 mL浓度为0.25 mol/L氢氧化钠溶液中进行氧化,双氧水的滴加时间为30～40 min;反应温度为60～65℃;酸化时间为50～60 min,苯并噻唑收率为85%。     

Preparation and properties of poly(Nε,Nε-dicarboxymethyl-l-lysine)

A new ampholytic homopolypeptide, $\text{poly}\text{(N}{}^{\mathrm{\epsilon }}\text{,N}{}^{\mathrm{\epsilon }}\text{-}\text{dicarboxy-methyl-}\text{l}\text{-lysine}\text{)}$, which has one tertiary amino and two carboxyl groups in the side chain has been derived from a hydrochloride salt of poly(L-lysine). The polymer in aqueous solution seems to be in the coil form with locally extended structure (LES) at neutral pH. In both the acidic and alkaline regions, the molar ellipticity of the polymer changes as a result of change in net charge on the side chain. The conformational changes may be from the coil with LES to other coiled forms. 5–7 M NaClO₄ and 80% aqueous methanol induce the α-helix in the polymer at neutral pH. Divalent cations, Cu²⁺ and Ca²⁺, do not induce any remarkably ordered structures such as α-helix or β-structure in the polymer in aqueous solution at any pH. Ultraviolet absorption studies show an absorption peak of the polymer-Cu²⁺ complex near 240 nm. Dependence of the peak intensity on pH at various q values ($\text{q =}\text{[}\text{Cu}{}^{\mathrm{2+}}\text{]}\text{[}\text{residue}\text{]}$) indicates the two steps of the complex formation. At q less than 0.64, the formation is described only with the first step. An average coordination number for Cu²⁺ at the first step was calculated to be about 2 by the method of Mandel and Leyte. The association constant of Cu²⁺ with the residue at the step was determined from the absorption data to be far smaller than that for the Cu²⁺-EDTA complex. The second step of the formation occurs in the case of large q but the absorption data for the second step cannot be obtained exactly due to precipitation.     

Wet Milling of Fe/Al/Al2O3 and Fe2O3/Al/Al2O3 Powder Mixtures

Wet milling of Al₂O₃-aluminide alloy (3A) precursor powders in acetone has been investigated by milling Fe/Al/Al₂O₃ and Fe₂O₃/Al/Al₂O₃ powder mixtures. The influence of the milling process on the physical and chemical properties of the milled powders has been studied. Particle refinement and homogenization were found not to play a dominant role, whereas plastic deformation of the metal particles leads to the formation of dislocations and a highly disarranged polycrystalline structure. Although no chemical reactions among the powder components in Fe₂O₃/Al/Al₂O₃ powder mixtures were observed, the formation of a nanocrystalline, ordered intermetallic FeAl phase in Fe/Al/Al₂O₃ powder mixtures caused by mechanical alloying was detected. Chemical reactions of Fe and Al particle surfaces with the atmosphere and the milling media lead to the formation of highly porous hydroxides on the particle surfaces. Hence the specific surface area of the powders increases, while the powder density decreases during milling. The fraction of Fe oxidized during milling was determined to be 0.13. The fraction of Al oxidized during milling strongly depends on the metal content of the powder mixture. It ranges between 0.4 and 0.8.     

Sintering of Si3N4-Y2O3-Al2O3

Sintering kinetics of the system Si₃N4-Y2O₃-Al₂O3 were determined from measurements of the linear shrinkage of pressed disks sintered isothermally at 1500° to 1700°C. Amorphous and crystalline Si₃N₄ were studied with additions of 4 to 17 wt% Y₂O₃ and 4 wt% A1₂O₃. Sintering occurs by a liquid-phase mechanism in which the kinetics exhibit the three stages predicted by Kingery's model. However, the rates during the second stage of the process are higher for all compositions than predicted by the model. X-ray data show the presence of several transient phases which, with sufficient heating, disappear leaving mixtures of β ' -Si₃N₄ and glass or β '-Si₃N₄, α '-Si₃N₄, and glass. The compositions and amounts of the residual glassy phases are estimated.     

Participation of lewis base on vinyl chloride polymerization with Al(C2H5)3CCl4 catalyst system

The polymerization of vinyl chloride has been investigated using an $\text{Al}\text{(}\text{C}{}_2\text{H}{}_5\text{)}{}_3\text{CCl}{}_4$ catalyst system in the presence of various Lewis bases. Effective Lewis bases are γ-butyrolactone, diglyme and diethylenetriamine which are multidentate. The rate of polymerization is dependent not only on the basicity of the Lewis base used but also on a coordination number of one. The latter is the predominant factor. For the effect of polymeric amines, a tentative hypothesis is discussed.     

Synthesis and Characterization of Ti0.33Ta0.33Nb0.33C and Ti0.33Ta0.33Nb0.33CxN1-x Whiskers

Ta_0.33Ti_0.33Nb_0.33C and Ta_0.33Ti_0.33Nb_0.33C _x N_{1− x} whiskers were synthesized via a carbothermal vapor-liquid-solid growth mechanism in the temperature range 900°-1450°C in Ar or N₂. The optimum temperature was 1250°C. Whiskers were obtained in a yield of 70-90 vol%. The whiskers were 0.5–1 µm in diameter and 10–30 µm in length. The starting materials that produced the highest whisker yield were: TiO₂, Ta₂O₅, Nb₂O₅, C, Ni, and NaCl. C was added to reduce the oxides, and Ni to catalyze whisker growth. NaCl was used as a source of Cl for vapor-phase transportation of Ta and Nb oxochlorides and Ti chlorides to the catalyst. The catalyst metal was recycled several times during the synthesis and was transported as NiCl₂( g ) according to thermodynamic calculations. The rate of formation and the chemical composition of the whiskers depended on the synthesis temperature, the choice of catalyst, and the atmosphere. At low temperatures, the whiskers were enriched in Nb and Ta, whereas the Ti content increased with increased synthesis temperature.