共查询到20条相似文献,搜索用时 78 毫秒
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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。 相似文献
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郑来昌 《精细与专用化学品》2000,(21)
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。 相似文献
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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。 相似文献
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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. 相似文献
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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。 相似文献
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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。 相似文献
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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... 相似文献
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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. 相似文献
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对甲氧基肉桂酸异辛酯合成新工艺 总被引:1,自引:0,他引:1
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%。 相似文献
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《Ceramics International》2022,48(10):13850-13854
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 HOP42? 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. 相似文献