β-甲基戊二酸的合成工艺优化

以氰乙酸乙酯为起始原料,经氨解反应、加成缩合反应和水解脱羧反应三步合成了β-甲基戊二酸,总收率为77％.对各步反应条件做了优化,开发了一条原料易得、操作简单、收率高、溶剂可循环使用、环境污染小的β-甲基戊二酸合成工艺路线,适于批量生产.采用间接法通过GC-MS分析了水解脱羧反应得到的β-甲基戊二酸和所含杂质,从而探讨了...     

水中吡喃并[2,3-d]嘧啶衍生物的洁净合成

以芳醛、丙二腈和2-氨基-4,6-二羟基嘧啶为原料, 以水为溶剂, 在80 ℃以苄基三甲基溴化铵为催化剂一步合成了一系列的吡喃并[2,3-d]嘧啶衍生物, 产物的结构通过IR, 1H NMR和元素分析表征. 该方法反应条件温和、操作简单、收率高. 而且水作为反应溶剂具有廉价、安全、无污染、产物易于分离的优点.     

4-二甲氨基巴豆酸的合成工艺研究

以N,N-二甲基氨基乙醇为原料,经TEMPO氧化、膦酰基乙酸三乙酯活化酯化、水解三步成功合成了4-二甲氨基巴豆酸,总收率81.2%。优选了TEMPO-Na Br-Na Br O3-Na NO2催化体系,确定甲酸乙酯为最佳溶剂,该步收率90.5%;研究了反应条件对酯化反应的影响,确定最佳条件为室温下,反应2h,二氯甲烷为溶剂,N,N-二甲基氨基乙醛、磷酰基乙酸三乙酯、氢化钠三者摩尔比为1∶1.5∶1.5,收率97%;水解反应采用盐酸甲醇溶液代替盐酸水溶液调节p H,选用体积比为乙腈∶丙酮=5∶1的混合溶剂搅拌析晶,收率92.5%。     

天然等同物覆盆子酮的合成工艺研究

以天然大茴香醛和发酵丙酮为起始原料,通过Claisen-Schmidt反应、选择性加氢、脱甲基实验得到天然级覆盆子酮。通过单因素实验和正交实验研究了三步反应的较佳工艺条件为:第一步,在氢氧化钠的作用下,氢氧化钠、大茴香醛以及丙酮的投料比为0.28:1:3,40℃反应1.5 h;第二步,催化剂雷尼镍的用量为1%,氢气压力为0.3 MPa,30℃反应14 h;第三步,以48%的氢溴酸做为催化剂,冰醋酸为溶剂,130℃,反应4h,得到天然级覆盆子酮,总收率:75.75%(以大茴香醛计),含量:98.65%,香气纯正。通过熔点、IR和~1H NMR对最终产物进行了结构表征。此工艺的研究为类似结构不饱和酮的选择性加氢提供了实验依据,且产品总收率较高,成本低,适合工业化生产。     

四溴双酚A双缩水甘油醚的合成研究

研究了四溴双酚A双缩水甘油醚的合成方法,探索了不同原料摩尔比、溶剂、反应温度、第一步反应中碱的用量以及第一步反应时间对反应的影响,并对产品进行了环氧当量的测定。     

一种聚氧乙烯醚链三头季铵盐表面活性剂的合成

以五甲基二乙烯三胺（PMDETA）、脂肪醇聚氧乙烯醚（FAPOE）和环氧氯丙烷（ECP）为原料,分两步合成了一种含聚氧乙烯醚链三头季铵盐的表面活性剂。对反应影响因素、产物结构与部分性能进行了分析与表征。结果表明：第一步反应n（ECP）：n（FAPOE）为2．5～3：1,溶剂为正己烷,四丁基溴化铵作相转移催化剂,无水K2CO3作缚酸剂,时间6～8h。第二步反应n（中间体）：n（PMDETA）为3．5—4．0：1,溶剂为正丁醇,时间40-45h;溶剂与时间是主要影响因素。定性表征符合产物结构：定量表征n（Cl^-）：n（阳离子部分）为3．4：1,略高于理论值。产物的表面活性高,1．0×10^-4mol／L水溶液的表面张力可降至6．65mN／m。     

一种萘并吡喃化合物的合成及其工艺研究

本文以4,4'-二甲氧基二苯甲酮、苯乙酮和呋喃甲醛为原料,采用新的路线,6步反应合成了一种新型萘并吡喃类化合物,借助核磁共振、质谱等检测手段对最终产物的结构进行了结构表征,并对其反应条件进行优化,提高了反应收率,最后应用紫外-可见吸收光谱对目标产物在不同溶剂中的光致变色性质进行了初步探索研究。     

间氨基茴香醚的合成

以间氨基苯酚为原料,经乙酰化、甲基化和碱水解合成了间氨基茴香醚,3步反应的收率分别为90.7%,82.8%和88.2%。最佳的甲基化反应条件为:间羟基乙酰苯胺56 mmol,n(间羟基乙酰苯胺)∶n(M e2SO4)∶n(NaOH)=1.0∶1.5∶1.2,回流反应8 h,四氯化碳为溶剂。     

FeCl_3催化吲哚烯丙醇Nazarov环化合成新型稠环吲哚

以吲哚-2-甲醛和取代苯乙酮为原料,经3步反应合成了10个吲哚烯丙基醇(5a~5j);以Fe Cl3·6H2O为催化剂,二氯甲烷为溶剂,5于40℃经分子内Nazarov环化反应,合成了10个新型稠环吲哚(6a~6j),其结构经1H NMR,13C NMR和HR-ESI-MS表征。     

磷钼钒杂多酸催化苯制苯酚的研究

将磷钼钒杂多酸应用于以过氧化氢作氧化剂,冰醋酸作溶剂的苯一步氧化制苯酚反应中,分别考察了杂多酸、过氧化氢和冰醋酸的用量,以及反应温度和反应时间等因素对苯制苯酚反应的影响,并通过单因素实验方法确定了较为适宜的工艺条件.     

A Novel Non-phosgene Process for the Synthesis of Methyl N-Phenyl Carbamate from Methanol and Phenylurea： Effect of Solvent and Catalyst

A novel environmentally benign process for the synthesis of methyl N-phenyl carbamate (MPC) from methanol and phenylurea was studied. Effect of solvent and catalyst on the reaction behavior was investigated. The IR spectra of methanol and phenylurea dissolved in different solvents were also recorded. Compared with use of methanol as both a reactant and a solvent, phenylurea conversion and selectivity to MPC increased by using toluene, benzene or anisole as a solvent, while phenylurea conversion decreased slightly by using n-octane as a solvent. The phenylurea conversion declined nearly 50% when dimethyl sulfoxide (DMSO) was used as a reaction media, and MPC selectivity decreased as well. The catalytic reaction tests showed that a basic catalyst enhanced the selectivity to MPC while an acidic catalyst promoted the formation of methyl carbamate and aniline. Moderate degree of basicity showed the best catalytic performance in the cases studied.     

Ring-opening polymerization of 1,5-dioxepan-2-one initiated by a cyclic tin–alkoxide initiator in different solvents

Ring-opening polymerization of 1,5-dioxepan-2-one initiated by 1,1,6,6-tetra-n-butyl-1,6-distanna-2,5,7,10-tetraoxacyclodecane was carried out in chloroform, dichloromethane, or 1,2-dichloroethane. Effects of reaction temperature, solvent, and monomer-to-initiator ratio were investigated. Polymerization kinetics showed a first-order dependence on the monomer for polymerization in chloroform and dichloromethane at 40°C. The kinetic order with respect to the initiator were a first order when dichloromethane was used as the solvent, the order in initiator changed, depending on the initiator concentration when chloroform was used. A maximum in molecular weight was observed at 40°C when chloroform was used as the solvent. The change of solvent did not markedly alter the polymerization rate or the molecular weight of the polymers prepared, as expected from the coordination insertion mechanism. Depolymerization of the polymers formed was observed when the reaction was allowed to continue after complete monomer conversion in chloroform as reaction medium at 40°C. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 3407–3417, 1999     

Optimization of reaction conditions for REM resin-bound quaternization reactions

A study into the effect of reaction variables on the quaternization of REM resin-bound tertiary amines was undertaken. The influence of resin matrix, solvent, reaction time, temperature, and amount of quaternization agent on the outcome of reaction was evaluated by reaction monitoring using (19)F NMR. The highest yields of tertiary amine products were seen when DMSO was used as reaction solvent in conjunction with a reaction time of 18 h at room temperature. The use of heating for extended reaction times tended to depress yields, indicating product cleavage during quaternization. Quaternization on PS-DVB resin was found to be more robust than reaction on PS-PEG matrices where yields were generally considerably lower than the observed conversions. DMSO was the most efficient reaction solvent for both resins despite poor swelling of the quaternization starting material.     

Solvent effects on methyl transfer reactions. 2. The reaction of amines with trimethylsulfonium salts.

The reaction of ammonia and pyridine with trimethylsulfonium ion has been studied in gas phase and solution. Density functional theory at the B3LYP/6-31+G level was used to describe the energy changes along the reaction coordinate in the gas phase, and the self-consistent isodensity polarizable continuum model (SCI-PCM) was used to calculate the effect of cyclohexane and dimethyl sulfoxide as the solvent on the energy changes. The effect of water as the solvent was studied using the Monte Carlo free energy perturbation method. The reaction with both ammonia and pyridine follows a similar rather convoluted path in gas phase, with the formation of several reaction complexes before and after the formation of the transition state. All the species found in gas phase persist in cyclohexane, yielding a reaction path very similar to that in gas phase but with significant differences in the relative energy of the critical points. In DMSO, the energy profile is greatly simplified by the disappearance of several of the species found in gas phase and in cyclohexane. The activation free energy increases with the polarity of the solvent in both reactions. Increasing the polarity of the solvent also increases the exothermicity of the reaction of trimethylsulfonium ion with ammonia and reduces it in the reaction with pyridine. In water, the free energy profile follows the same trend as found for DMSO, and free energy of activation is calculated to be larger by about 2-3 kcal/mol. This is in good agreement with an experimental measurement of the effect of solvent on the rate of reaction.     

Effect of solvent on catalytic performance of anhydrous catalyst in acetylene dimerization to monovinylacetylene

The production of monovinylacetylene (MVA) through Cu(I)-catalyzed acetylene dimerization reaction was performed in different reaction media. Based on the analyses of crystals precipitated from the catalyst solution and UV-Vis spectra of the catalysts, the reaction mechanism and solvent dependence were studied. The highest yield of MVA can be obtained when dimethylformamide is used as solvent because of its strong coordination ability to Cu(I). The activation of C≡C bond is presumed to be improved when the catalytic metal ion is coordinated by a solvent with less steric hindrance and electron-rich coordination atom. The results of the present study provide a possible way to accelerate the metal-catalyzed homogeneous reaction of alkyne substrates through careful selection of a solvent.     

Proton transfer in nanoconfined polar solvents. 1. Free energies and solute position

The reaction free energy curves for a model phenol-amine proton-transfer system in a confined CH3Cl solvent have been calculated by Monte Carlo simulations. The free energy curves, as a function of a collective solvent coordinate, have been obtained for several fixed reaction complex radial positions (based on the center-of-mass). A smooth, hydrophobic spherical cavity was used to confine the solvent, and radii of 10 and 15 A have been considered. Quantum effects associated with the transferring proton have been included by adding the proton zero-point energy to the classical free energy. The results indicate the reaction complex position can be an important component of the reaction coordinate for proton-transfer reactions in nanoconfined solvents.     

煤与废塑料共液化中氢转移的示踪试验研究

采用放射性同位素3H标记的四氢萘溶剂进行了先锋褐煤与低密度聚乙烯（LDPE）的共液化示踪试验,并考察了钼灰（FAMo）和Fe2O3+S催化剂的影响。应用液体闪烁计数器测量了各液化产物中的放射性活度,以研究煤与废塑料共液化中的氢转移。结果表明：在先锋褐煤与LDPE塑料共液化反应的初始阶段,存在着四氢萘溶剂的供氢作用,而且这种供氢作用不受催化剂的影响,只是热力作用的结果。使用加氢蒽油（HAO）和四氢萘（THN）溶剂混和物作为共液化溶剂时,先锋褐煤与LDPE共液化反应初期的溶剂供氢还存在着竞争转移,其主要取决于溶剂的脱氢能力。     

Dramatic solvent and hydration effects on the transition state of soybean peroxidase

Enzymes are shown to function in nonaqueous media; however, relatively little information is available on the influence of the organic solvent as well as its associated water content on the properties of the enzymatic transition states. A better understanding of these effects will be useful in developing kinetic models that can then be used to predict optimal solvent and substrate choices for enzymatic reactions in organic media. The influence of the reaction media on soybean peroxidase-catalyzed oxidation of para-substituted phenols was studied using Hammett analysis for several organic solvent systems. The catalytic activity and substrate specificity of the enzyme are influenced by the nature of the solvent and its associated hydration. These findings may allow one to draw conclusions about the reaction mechanism and the roles of solvent and solvent hydration on enzyme function.     

Study on the alkylation reaction of guanine and N-acetylguanine and the synthesis of 1''''-C alkylated carba-DHPG analogues

The alkylation reaction of guanine and N-acetylguanine with model compounds such as isopropyl bromide or 4-heptyl tosylate were studied. The reaction conditions such as temperature, solvent, base, and catalyst were examined for their effects on the reaction rate, and the yield and regioselectivity of the coupling reaction. The highest yield was obtained by using DMSO as the solvent. The reaction proceeded in a homogenous manner to give higher yield of 9-N and 7-N substituted product in a mole ratio of 1:1. The ratio could be raised to 2:1 if dibenzo-18-crown-6 was used as a catalyst. Using the above procedure, three carba-DHPG analogues bearing different 1'-C alkyl side chains were synthesized.     

溶剂对固相反应法制备H7PW12O42掺杂聚苯胺的影响

利用固相反应法,分别以微量的水和乙腈作为溶剂,制备了磷钨酸(H7PW12O42)掺杂聚苯胺,并以红外光谱(FTIR),电子扫描显微镜(SEM),X射线衍射(XRD),循环伏安(cyclic voltamogram)等测试方法对聚苯胺进行了表征。结果表明,固相反应法合成的聚苯胺分子链排列有序,晶化率较好,并且表现出有较好的电化学稳定性。而以微量的乙腈作为溶剂通过固相反应法得到的磷钨酸掺杂聚苯胺在颗粒形貌、结晶性、导电率等方面均优于相同条件微量的水作为溶剂时的掺杂聚苯胺。