Preparation,Characterization of Dawson-type Heteropoly Acid Cerium（Ⅲ） Salt and Its Catalytic Performance on the Synthesis of n-Butyl Acetate

A novel cerium(Ⅲ) salt of Dawson type tungstophosphoric acid(Ce2P2W18O62·16H2O) was prepared by doping cerous nitrate in H6P2W18O62·13H2O powder and characterized by thermogravimetry and differential thermal analyses(TG/DTA),Fourier transform infrared spectroscopy(FT-IR),X-ray powder diffraction(XRD),pyridine infrared spectroscopy(Py-IR) and scanning electron microscopy(SEM).Its catalytic activity was evaluated by the probe reaction of synthesis of n-butyl acetate with acetic acid and n-butanol.The effects of various parameters such as molar ratio of n-butanol to acetic acid,reaction temperature,reaction time,and catalyst amount have been studied by single factor experiment.The results show that Ce2P2W18O62·16H2O behaved as an excellent heterogeneous catalyst in the synthesis of n-butyl acetate.The optimum synthetic conditions were determined as follows︰molar ratio of n-butanol to acetic acid at 2.0︰1.0,mass of the catalyst being 1.44% of the total reaction mixture,reaction temperature of 120 ℃ and reaction time of 150 min.Under above conditions,the conversion of acetic acid was above 97.8%.The selectivity of n-butyl acetate based on acetic acid was,in all cases,nearly 100%.The catalysts could be recycled and still exhibited high catalytic activity with 90.4% conversion after five cycles of reaction.It was found by means of TG-DTA and Py-IR that the catalyst deactivation was due to the adsorption of a complex of by-product on the active sites on catalysts surface or the catalyst loss in its separation from the products.Compared with using sulfuric acid as catalyst,the present procedure with Ce2P2W18O62·16H2O is a green productive technology due to simple process,higher yield,catalyst recycling and no corrosion for the production facilities.

Reactive dividing-wall column for the co-production of ethyl acetate and n-butyl acetate

Reactive dividing-wall column(RDWC) technology plays a critical role in the energy saving and high efficiency of chemical process.In this article, the process of co-producing ethyl acetate(EA) and n-butyl acetate(BA) with RDWC was studied.BA was not only the product, but also acted as entrainer to remove the water generated by the two esterification reactions.Experiments and simulations of the co-production process were carried out.It was found that the experimental results were in good agreement with the simulation results.Two kinds of RDWC structures(RDWC-FC and RDWC-RS) were proposed, and the co-production process operating parameters of the two types of RDWC were optimized by Aspen Plus respectively.The optimal operating parameters of the RDWC-FC were determined as follows: 0.6 of the reflux ratio of aqueous phase(RR), 0.66 of the vapor split(R_V) and 0.51 of the liquid split(R_L).And the optimal operating parameters of the RDWC-RS were shown as follows: RR was 0.295 and R_V was 0.61.Furthermore, the energy saving analysis of the co-production process was based on the annual output of 10000 tons of EA, compared with the traditional reaction distillation(RD) to prepare EA and BA, the reboiler duty of the RDWC-FC column could save 20.4%, TAC saving 23.6%; RDWC-RS reboiler energy consumption could save 17.0%, TAC 22.2%.

Vapor-Liquid Equilibria for Dimethyl Carbonate-n-Butyl Acetate Binary System at 101.325kPa

1 INTRODUCTIONDimethyl Carbonate(CH_3OCOOCH_3,DMC) is chemical with methyl group (CH3-) and car-bonyl group(-CO-) in its molecule.Dimethyl carbonate can be used to replace the acutelypoisonous dimethyl sulfate and phosgene as methylating and carbonylating agent in the syn-thesization of many useful organic substance,such as aromatic polycarbonates(high

Preparation, Characterization and Catalytic Performance of La-SO_4^(2-)/SBA-15 in Esterification of Acetic Acid with n-Butanol

La-SO42-/SBA-15 was synthesized with various amounts of lanthanum via incipient-wetness impregnation. Characterization was done by X-ray diffraction（XRD）, transmission electron micrographs（TEM）, nitrogen adsorption, FTIR spectroscopic analysis, thermogravimetric analysis, and the total amount of acidity of catalyst was estimated by TPD of NH3. The results indicate that lanthanum has been incorporated into SBA-15 molecular sieve. The prepared materials（La-SO42-/SBA-15） keep the highly ordered mesoporous two-dimensional hexagonal structure and do not change the mesoporous channel structure of the support SBA-15. The catalyst showed best catalytic activity in the synthesis of n-butyl acetate. The optimum conditions of the esterification by orthogonal experiments were studied： the molar ratio of n-butanol to acetic acid 1：1.2, the amount of catalyst 7.5%, reaction time 80 min. The yield of n-butyl acetate could reach 93.2% under the optimum conditions. The catalyst was recyclable, cost effective and environmental friendly.

二维气相色谱法测定车用汽油中的甲缩醛、碳酸二甲酯、乙酸仲丁酯、乙酸异丁酯和N-甲基苯胺

针对常规车用汽油中非常规添加物的难分离问题,采用二维气相色谱分析技术,将在非极性毛细管色谱柱中与汽油组分难分离的物质——甲缩醛、碳酸二甲酯、乙酸仲丁酯、乙酸异丁酯和N-甲基苯胺切换至极性毛细管色谱柱进行分离,并采用双氢离子火焰检测器（FID）检测,内标法定量。结果表明,采用二维气相色谱分析技术,甲缩醛、碳酸二甲酯、乙酸仲丁酯、乙酸异丁酯和N-甲基苯胺5个组分均能得到较好的分离,回收率在97.9%~102.2%,6次重复测定的相对标准偏差小于2.0%,定量数据准确可靠;在实验范围内,各组分线性响应良好,检测限为质量分数0.01%。该方法简单可靠,重复性和再现性均能满足常规分析要求。

固体酸S2O8^2-/Nb2O5/La^3+的制备、表征及催化合成乙酸正丁酯

以Nb2O5为载体,浸渍法研制固体酸(S2O8^2-/Nb2O5/La+)催化剂,经SEM、XRD和EDS表征,考察了固体酸的焙烧温度、陈化时间及S2O8^2-浓度等因素对该催化剂催化活性的影响。结果表明:在(NH4)2S2O8浓度为1 mol/L、浸渍时间18 h、w(La^3+)=3%(基于Nb2O5的质量)、焙烧温度为500℃时,制备出最高催化效果的催化剂。接着考察了其催化合成乙酸正丁酯的催化活性,通过正交实验确定了反应的最佳条件:n(正丁醇)/n(冰醋酸)=2.0/1.0、催化剂用量w(S2O8^2-/Nb2O5/La^3+)=2.9%、反应温度为125℃,反应时间为3.0 h,酯化率为95.7%。催化剂循环利用3次后仍有90.1%的酯化率。

稀土复合固体超强酸SO_4^(2-)/ZrO_2-Nd_2O_3催化合成乙酸正丁酯

以纳米稀土复合固体超强酸SO42-/ZrO2-Nd2O3为催化剂,乙酸和正丁醇为原料合成乙酸正丁酯。通过正交试验考察了反应条件对酯化率的影响。结果表明,最佳的反应条件是:乙酸用量为0·2mol时,乙酸与正丁醇摩尔比为1:1·4,催化剂用量为1·0g,回流分水反应时间为120min。在此条件下,酯化率可达98·8%。实验还发现,稀土复合固体超强酸SO42-/ZrO2-Nd2O3可多次重复使用并可活化再生,是一种稳定性高、选择性好的新型环境友好催化剂。

Keggin型P-V-Mo-W四元杂多酸催化合成乙酸正丁酯

采用正交试验设计研究了Keggin型P-V-Mo-W四元系列杂多酸H4PVMoxW11-xO40·nH2O(x=1,2,3,4)催化冰乙酸和正丁醇合成乙酸正丁酯的反应,得出最佳反应条件如下:正丁醇与冰乙酸的物质量比为1.2∶1,催化剂的用量为冰乙酸质量的0.5%,反应时间为40 min,酯化率达到88.52%。该系列杂多酸的酯化率随钨原子数的增加而提高。

Br?nsted-Lewis酸性离子液体催化合成乙酸正丁酯

合成了[HO3SC3-NEt3]Cl,与ZnCl2、FeCl3、AlCl3、CuCl2配位制备Bronsted-Lewis酸性离子液体[HO3SC3-NEt3]XCln+1,通过傅里叶变换红外光谱和核磁氢谱对[HO3SC3-NEt3]Cl结构进行表征。利用Bronsted-Lewis酸性离子液体催化合成乙酸正丁酯,通过对各种离子液体的腐蚀性和催化性能的综合分析。结果表明,当以[HO3SC3-NEt3]ZnCl3为催化剂,醇酸摩尔比为1∶1.2,催化剂用量为5%(以正丁醇计量),反应温度为95℃,反应时间为4h,环己烷为带水剂时,乙酸正丁酯的收率可达到96.94%。

离子液体N-甲基咪唑对甲苯磺酸盐催化剂的制备及应用

采用一步法制备Brφnsted酸性离子液体N-甲基咪唑对甲苯磺酸盐催化剂([Hmim]TsO),并对其进行了红外光谱、拉曼光谱等表征。将其应用于醋酸和正丁醇的酯化反应,详细考察了离子液体用量、反应时间、醇酸物料比、反应温度等因素对酯化反应的影响,并确定了较佳反应条件为:温度95～98℃,n(丁醇)∶n(醋酸)=1.2∶1,离子液体用量为反应物总质量的20.0%,反应时间6h,酯化率可达到85.0%。同时,[Hmim]TsO离子液体循环使用6次后,酯化率仍可达到78.2%。

N-(α-甲基-丁酯基)马来酰亚胺微乳液聚合的动力学研究

以十二烷基硫酸钠为乳化剂,过硫酸钾为引发剂,使N (α 甲基 丁酯基)马来酰亚胺的微乳液聚合,并对其动力学进行了研究。考察了引发剂浓度、乳化剂浓度、单体浓度对聚合的影响,得到三者的曲线斜率分别为0.5,1.17,1.22。

Bronsted-Lewis双酸性离子液体催化合成乙酸正丁酯

以3-氨基-1-丙磺酸、氯化锌、盐酸为原料制备了一系列Bronsted-Lewis双酸性离子液体。离子液体中磺酸基提供Bronsted酸性,阴离子提供Lewis酸性。采用FTIR、1HNMR、13CNMR、元素分析对合成的离子液体进行了结构表征;对离子液体的Bronsted酸性、Lewis酸性、腐蚀性进行了测定。使用该离子液体催化合成了乙酸正丁酯并利用响应曲面法考察了最佳反应条件。结果表明,在反应温度103℃,催化剂[NH3C3H6SO3H]Cl/0.75ZnCl2(0.75代表3-氨基-1-丙磺酸盐酸盐与氯化锌物质的量比为1.00∶0.75)用量为正丁醇质量的10.03%,n(乙酸)∶n(正丁醇)=1.00∶1.22,反应时间4.92 h,带水剂环己烷用量为正丁醇质量的20%条件下,乙酸正丁酯收率可达97.28%。[NH3C3H6SO3H]Cl/0.75Zn Cl2重复使用5次后,催化剂活性没有明显降低。

Experimental Study on Liquid-Liquid Equilibria of Alcohol- Ester-Water-CaCl_2 System

The binary liquid-liquid equilibrium(LLE) data for salt-containing systems of 1-butanol+water+CaCl2, n-butyl acetate+water+CaCl2 and ethyl acetate+acetic acid+water+CaCl2 were determined and the salt effect was analyzed. The results showed that an obvious salt effect could be identified for the systems of 1-butanol+water+CaCl2 and ethyl acetate+acetic acid+water.

乙酸正丁酯的实验室合成条件优化研究

以冰醋酸和正丁醇为原料,浓H_(2)SO_(4)作催化剂,无水Mg SO4为干燥剂合成乙酸正丁酯,研究了投料比、反应时间、反应温度、浓H_(2)SO_(4)用量等对产率和纯度的影响。得出最佳反应条件为:冰醋酸与正丁醇的物质的量之比为1∶1.05,冰醋酸的用量为14.00g,浓H_(2)SO_(4)用量为1.00m L,回流反应时间为40min。在该条件下合成乙酸正丁酯,纯度超过98%,产率可达80%以上。

Cerium modified Y/SBA-15 composite molecular sieve catalyzed synthesis of n-butyl acetate

A novel Ce-Y/SBA-15 catalyst was prepared by modifying HY/SBA-15 microporous-mesoporous composite molecular sieve with cerium using the impregnation method. The characterization results from scanning electron microscopy/energy dispersive X-ray dispersive spectroscopy（SEM/EDS）, transmission electron microscopy（TEM）, and X-ray fluorescence（XRF） studies indicated that the Ce-modified catalyst maintained the microporous-mesoporous structure of Y/SBA-15. The Ce ions were found to be uniformly dispersed in the pores of the molecular sieve without aggregation. The results from pyrolysis coupled-Fourier transform infrared spectroscopy（Pyridine-FTIR） and temperature programmed desorption of ammonia（NH3-TPD） showed that the loading of cerium caused the hydroxyl group in the catalyst to display stronger Bronsted acidity. The efficiency of the modified Ce-Y/SBA-15 catalyst was evaluated by using it to catalyze the synthesis of n-butyl acetate. The optimal synthesis conditions were determined by orthogonal experiments. The highest esterification yield of 94.4% was obtained when the reaction time was 2.0 h, with acid/alcohol molar ratio of 1：1.2, and catalyst loading of 10 wt.%. The results in this study demonstrated that the loading of cerium and the structure of Y/SBA-15 microporous-mesoporous composite molecular sieve helped in improving the catalytic activity of this acidic catalyst.

Dawson结构磷钨酸的制备、表征及催化绿色合成乙酸正丁酯工艺研究

制备了H6P2W18O62.13H2O催化剂,并通过FT-IR、UV-Vis、TG-DSC对催化剂进行表征.以乙酸正丁酯合成反应为探针考察催化剂的催化性能.研究了磷钨酸用量、醇酸比、反应时间和反应温度对反应的影响,并提出可能的催化机理.结果表明,最优的反应条件是:催化剂用量为0.72%(按反应体系总质量计算),醇酸比为2.0︰1.0,反应时间为2.0 h,反应温度为125℃,在此条件下酯化率可达96.83%.

ZnMn_2O_4纳米催化剂制备及催化合成乙酸正丁酯

利用共沉淀法制备了四方晶系锌锰复合氧化物ZnMn2O4纳米催化剂,X射线粉末衍射（XRD）和透射电子显微镜（TEM）结果表明,所合成的催化剂为粒径均匀的纳米粒子,平均粒径在20-50 nm,具有较好的分散性,对乙酸正丁酯的合成有较高的催化活性。确定了适宜的酯化反应条件,以焙烧温度为300℃制备的ZnMn2O4为催化剂,在催化剂用量为0.3%（以反应物总质量计）、n（酸）∶n（醇）=1.8∶1、反应时间为4 h、酯化反应温度120℃的条件下,酯化率可达92.53%。

La-SO4^2-改性SBA-15分子筛的制备、表征及催化合成乙酸正丁酯

用固体研磨法对 SBA-15分子筛进行 La-SO_4^(2-)改性,制备了 La-SO_4^(2-)改性 SBA-15分子筛(La-SO_4^(2-)/SBA-15)催化剂,采用 X 射线衍射、红外光谱和低温 N_2吸附-脱附、热重-差热分析、NH_3-程序升温脱附等方法对 La-SO_4^(2-)/SBA-15催化剂进行了表征。表征结果显示,La 已进入 SBA-15分子筛中,制得的 La-SO_4^(2-)/SBA-15催化剂保持高度有序的二维六方介孔结构。用 Hammett 指示剂法测得 La-SO_4^(2-)/SBA-15催化剂的表面酸强度(H_0)为2.77<H_0≤3.30,酸量为0.597 2 mmol/g。采用 La-SO_4^(2-)/SBA-15催化剂催化合成乙酸正丁酯,优化的合成反应条件为:n(冰乙酸):n(正丁醇)=1:1.4,催化剂用量为冰乙酸质量的7.5%,反应时间为120 min,在此条件下酯化率为90.6%。

含铈固体超强酸SO_4^(2-)/ZrO_2-CeO_2催化合成乙酸丁酯的研究

以固体超强酸 SO42 - / Zr O2 - Ce O2 作催化剂 ,冰醋酸和正丁醇为原料合成了乙酸丁酯。采用正交实验法对影响反应的因素进行了考察。结果表明 :最佳反应条件为 n(醇 )∶ n(酸 ) =2∶ 1,催化剂用量为反应混合物总量的 1.5 %(质量分数 ) ,反应时间为 3h,酯化率可达 92 .6 %。

萃取富集-电感耦合等离子体原子发射光谱法测定矿石中镓

采用HNO3、HF和H2SO4溶解矿石样品,在6 mol/L HCl的介质中以乙酸丁酯萃取氯化镓,再加入适量的水从乙酸丁酯中反萃取氯化镓,从而富集痕量镓并使镓与其它干扰元素分离,在波长294.364{114}nm处以电感耦合等离子体原子发射光谱法测定了样液中的镓。对萃取机理、萃取分离技术、干扰元素的消除进行了探讨,并对仪器参数进行了优化。溶液中镓原子发射光谱强度与ρ（Ga）在0~3μg/mL范围内呈良好的线性关系,校准曲线相关系数为0.999 9,方法检出限为0.052μg/mL。用本方法测定了标准物质中镓的含量,测定值与认定值吻合,相对标准偏差（n=6）为0.85%~1.9%。