羟戊醛的合成及其动力学研究

羟戊醛是多种精细化学品合成的重要中间体。采用正交实验设计法考察羟醛缩合制备羟戊醛的反应规律,并对缩合反应的动力学进行了研究。最佳反应条件：碳酸钠催化剂的用量为0.029mol/molHCHO,n（甲醛）∶n（异丁醛）=1∶1,反应时间5h,反应温度66℃。在此条件下产物收率可达97.6%。实验验证了推导出的合成羟戊醛反应的动力学模型,并得出反应速率方程。     

羟基新戊醛合成工艺及其动力学

羟基新戊醛是合成多种精细化学品的重要中间体。以叔胺溶液为催化剂,利用正交实验法优化了甲醛异丁醛缩合制备羟基新戊醛的工艺条件,并考察了缩合反应动力学。由正交实验结果得到最佳反应条件为:催化剂的用量为3%质量分数,反应温度75℃,甲醛与异丁醛的物质的量之比为1.1:1,反应压力0.3 MPa,反应时间80 min,在此条件下产物收率可达98.33%。动力学的研究结果表明:缩合主副反应的表观活化能分别为40.801 k J/mol和64.088 k J/mol;主反应对异丁醛、甲醛反应级数分别为1和1.2,副反应对羟基新戊醛的反应级数为2。通过残差分析和统计检验,表明动力学模型是适定的。     

三羟甲基丙烷的应用

一、性质及制法三羟甲基丙烷 CH_3CH_2C(CH_2OH)_3(又名三甲醇基丙烷,2,2—二羟甲基丁醇)简称 TMP,是一种重要的精细化工产品中间体,在精细化工生产中占有极其重要的地位。TMP 是无嗅、无色,有甜味的吸湿性晶体或粉末,密度134.17g/cm~3(20℃),沸点292℃,熔点58～60℃。易溶于     

异戊醛Tishchenko反应法合成异戊酸异戊酯

本文介绍了异戊酸异戊酯的4种合成方法。与其它方法相比,Tishchenko反应法以来源更容易的异戊醛为原料,从异戊醛一步合成异戊酸异戊酯,产品收率和选择性都比较高,是一种有效的一步合成方法,用该法合成的产品更适合于做食用香料。     

多聚甲醛和异丁醛合成羟基戊醛的工艺研究

针对采用甲醛水溶液合成新戊二醇传统工艺过程废水排放和副反应多等缺点。提出采用异丁醛（IBD）和多聚甲醛（PFA）在三乙胺（TEA）催化下制备新戊二醇（NPG）的中间产物羟基戊醛（HPA）的新方法。考察了溶剂种类与溶剂含量、原料配比、反应温度和反应时间以及催化剂用量对HPA收率的影响。得到的最佳工艺条件为：反应温度75℃，n（PFA）：n（IBD）：n（TEA）=1．07：1：0．06，反应时间3h。经过GC分析，IBD转化率为98％以上，HPA收率94％以上。     

甲醛和异丁醛缩合加氢合成新戊二醇的研究

对甲醛与异丁醛(IBD)缩合制羟基新戊醛(HPA)及HPA加氢制新戊二醇(NPG)进行了研究。以有机胺为催化剂,通过反应工艺条件的优化,异丁醛与甲醛缩合反应中IBD的转化率大于99%,HPA的选择性大于96%。在HPA加氢制NPG反应中,详细考察了铜基加氢催化剂的制备工艺和反应条件对HPA加氢制NPG反应的影响。结果表明,在较优反应条件下,HPA的转化率大于99%,NPG的选择性大于97%,且加氢催化剂稳定性良好,连续运行2000h未见明显失活。     

异戊醛的合成

以异戊醇为原料,采用铜固定床反应器,在反应温度300℃,异戊醇与水配比为97/3,反应停留时间为1.5秒条件下,催化剂连续使用500小时,反应的转化率和选择性未见明显变化,适合工业化大生产。     

2,2-二羟甲基庚醛的合成工艺研究

以甲醛和庚醛为原料,经羟醛缩合反应合成了2,2-二羟甲基庚醛(DMH)。羟醛缩合反应的最佳工艺条件为:反应温度35℃,n(甲醛)∶n(庚醛)∶n(NaOH)=4∶1∶1.3,缩合剂为10%NaOH溶液,反应时间为5h。加甲酸中和碱,经精制DMH的收率达到67.8%。DMH的结构用红外光谱(IR)表征。     

探讨2,2-二羟甲基丁酸的合成方法

2，2-二羟甲基丁酸是一种具有多官能团的新型功能性单体。可广泛应用于水性聚氨酯、水溶性聚酯、水性环氧树脂、胶粘剂、涂饰剂工业等方面，本文详细综述了2，2-二羟甲基丁酸的合成方法。     

2,2-二羟甲基庚醛的合成工艺研究

以甲醛和新蒸庚醛为原料,经羟醛缩合反应合成了2,2-二羟甲基庚醛(DMH)。羟醛缩合反应的最佳工艺条件为:反应温度为35℃,n(甲醛):n(庚醛):n(NaOH)=4:1:1.3,缩合剂为w(NaOH)=10%溶液,反应时间为5h。加甲酸中和碱,经精制DMH的收率达到67.8%。2,2-二羟甲基庚醛的结构用红外光谱(IR)表征。     

Experimental study and model of reaction kinetics of heterogeneously catalyzed methylal synthesis

Reaction kinetics of the heterogeneously catalyzed formation of methylal from aqueous methanolic formaldehyde solutions are studied in a plug flow reactor at 323, 333 and 343 K using the acidic ion exchange resin Amberlyst 15 (Rohm and Haas) as catalyst. Parameters of an activity-based pseudo-homogeneous reaction kinetic model are fitted to the experimental results. The model is based on the true speciation in the reacting solution and explicitly includes the oligomerization reactions of formaldehyde in aqueous methanolic solutions. The reaction kinetic model describes the experimental data well and is suited for process simulations in which both chemical reactions and phase equilibria have to be described simultaneously.     

尿囊素合成新工艺

研究了原料乙二醛在酸性、常压条件下,以氧化氮为催化剂,经催化氧化后得到的生成物无需另加酸性催化剂直接与尿素缩合制得尿囊素的新工艺。考察了氧化和缩合反应中反应温度、原料配比、反应时间等因素的影响,确定了适宜的合成条件:乙二醛质量分数为25%,酸醛物质的量比为0.25,氮醛物质的量比为0.17,乙醛酸与尿素的物质的量比为1∶4,氧化反应温度为45℃,时间为2 h,缩合反应温度为75℃,时间为3 h,在此条件下,尿囊素的收率为61.99%。     

循环一锅法合成高纯度大粒径螺二醇

以甲醛、异丁醛和季戊四醇为主要原料,在催化剂作用下利用循环一锅法合成螺二醇。通过正交优化实验,考察了物料配比、温度、反应时间、溶剂量以及催化剂对两步法合成螺二醇收率的影响,确定了合成螺二醇最佳工艺条件,在该适宜条件下,开发了循环一锅法的制备工艺,即n(甲醛):n(异丁醛):n(季戊四醇)=2.85:2.85:1,反应温度75℃,反应时间9 h,产品总收率和纯度可达95.4%和99.9%。采用~1HNMR和HPLC确定了螺二醇产品结构和纯度。     

循环-锅法合成高纯度大粒径螺二醇

以甲醛、异丁醛和季戊四醇为主要原料,在催化剂作用下利用循环一锅法合成螺二醇。通过正交优化实验,考察了物料配比、温度、反应时间、溶剂量以及催化剂对两步法合成螺二醇收率的影响,确定了合成螺二醇最佳工艺条件,在该适宜条件下,开发了循环-锅法的制备工艺,即n（甲醛）：n（异丁醛）：n（季戊四醇）=2．85：2．85：1,反应温度75℃,反应时间9h,产品总收率和纯度可达95．4％和99．9％。采用。HNMR和HPLC确定了螺二醇产品结构和纯度。     

Effect of chloralkanes on the phenyltrichlorosilane synthesis by gas phase condensation

To enhance the process of phenyltrichlorosilane synthesis using gas phase condensation, a series of chloralkanes were introduced. The influence of temperature and chloralkane amount on the synthesis wa...     

氯代烷烃对气相缩合法合成苯基三氯硅烷的影响(英文)

To enhance the process of phenyltrichlorosilane synthesis using gas phase condensation, a series of chloralkanes were introduced. The influence of temperature and chloralkane amount on the synthesis was studied based on the product distribution from a tubular reactor. The promoting effect of chloralkane addition was mainly caused by the chloralkane radicals generated by the dissociation of C–Cl bond. The promoting effect of the chloromethane with more chlorine atoms was better than those with less chlorine atoms. Intermediates detected from the reactions with isoprene and bromobenzene demonstrated that both trichlorosilyl radical and dichlorosilylene existed in the reaction system in the presence of chloralkanes. A detailed reaction scheme was proposed.     

二氢茉莉酮酸甲酯合成新工艺

介绍了以正戊醛和环戊酮为原料，由羟醛缩合脱水得到２－戊叉环戊酮，给异构化生成中间体２－戊基－２－环戊烯－１－酮，后者再与丙二酸二甲酯发生加成反应，最后脱羧分４步合成二氢茉莉酮酸甲酯的新工艺。     

对甲氧基肉桂酸异辛酯合成新工艺

用茴香醛、丙二酸二乙酯和异辛醇为主要原料,以L-脯氨酸/磷酸钾为催化剂,无水乙醇为溶剂,经Knoenenagel反应合成对甲氧基肉桂酸乙酯中间体,收率达83.7%。在对甲苯磺酸催化作用下,对甲氧基肉桂酸乙酯与异辛醇进行酯交换反应得到对甲氧基肉桂酸异辛酯,收率达92.3%。     

1,1,1,3,5,5,5-七甲基三硅氧烷的合成研究进展

对1,1,1,3,5,5,5-七甲基三硅氧烷（MDHM）的合成方法进行了评述;在此基础上,对甲基氯硅烷的水解、缩合反应机理进行了分析,并指出了今后合成MDHM的研究方向。     

Solid-state synthesis and process optimization of bone whitlockite

Bone whitlockite (WH) is an important calcium phosphate (CaP) owing to its excellent biological properties. It is the second most abundant bone inorganic phase. A lot of work has been done on other CaPs like hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP) that are easy to synthesize. The synthesis of bone whitlockite is challenging due to its instability in comparison to other CaPs and its synthesis and presence in the body have not been fully acknowledged yet. Synthesis of WH using liquid precipitation method and effect of different parameters on its phase stabilization has been reported earlier. In this study, we are reporting a facile synthesis method for WH using a solid-state reaction. The reaction was carried out by mixing, grinding, and heat-treating the precursors at high temperatures without any medium under the ambient environment. The product obtained was characterized by using x-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FTIR), Raman spectroscopy, Scanning electron microscopy (SEM), and thermogravimetric (TGA) analysis. XRD analysis confirmed that the synthesized material has a whitlockite crystalline phase while FTIR and Raman spectroscopic analysis confirmed the presence of HOP₄^2? a peak that is a characteristic of bone whitlockite. The particles synthesized have a size below 50 nm and are stable below 700 ^°C. The reported method provides a facile synthetic route for mass production of WH.