固体碱催化脂肪酸甲酯甘油解制备单甘酯

以自制La2O3/Mg O固体碱为催化剂,采用脂肪酸甲酯甘油解合成单甘酯;采用薄层色谱、柱色谱、FTIR、1HNMR对产品进行了分离和鉴定;考察了反应温度、甘油与脂肪酸甲酯投料比、反应时间以及催化剂用量对单甘酯产率的影响。结果表明,合成产物单甘酯的红外光谱图与其标准品红外谱图相符;1HNMR数据表明,产品单甘酯为亚油酸单甘酯和棕榈酸单甘酯的混合物;合成单甘酯的最适宜条件为:反应温度240℃,催化剂添加量0.75%(以脂肪酸甲酯质量计),投料比n(甘油)∶n(脂肪酸甲酯)=2∶1,反应时间2.5 h;在该条件下单甘酯产率达70.53%。     

焙烧温度对Mg-Zn复合氧化物催化剂结构与催化性能的影响

采用共沉淀法制备Mg-Zn复合氧化物催化剂,着重考察了焙烧温度对催化剂结构和催化性能的影响,并将其用于催化大豆油甘油解合成单甘酯(MAG)。利用XRD、BET、SEM和HRTEM等分析手段对Mg-Zn复合氧化物催化剂进行表征。不同焙烧温度下,Mg-Zn复合氧化物催化剂碱强度H_在15. 0～17. 2范围时,催化剂MZ800碱量最大,碱强度是影响催化剂活性的主要因素。由HRTEM分析发现,800℃时催化剂出现六边形结构,这是由于Zn-Mg-O晶格的生成。且Mg-Zn复合氧化物催化剂中Zn O(101)处晶面间距(0. 024 2 nm)略小于标准卡片六方晶相Zn O(101)晶面间距(0. 248 nm)。结果表明,适宜的焙烧温度为800℃,此时大豆油转化率为96. 5%,MAG收率为53. 4%。     

Mg-Al类水滑石催化大豆油酯交换制备生物柴油

采用共沉淀法制备了不同n(Mg)/n(Al)比的Mg-Al类水滑石,在不同温度下焙烧得到复合氧化物,作为大豆油与甲醇反应制备生物柴油的催化剂。结果表明,未焙烧Mg-Al类水滑石的催化活性较差,而n(Mg)/n(Al)=3的类水滑石在450℃焙烧时具有极高的催化活性。在反应温度65℃,醇/油15,催化剂用量为大豆油质量的2%,反应3 h,生物柴油产率可达97.4%。催化剂回收再用性能良好,重复使用3次,生物柴油收率仍在90%左右。     

负载型对甲苯磺酸催化合成乙二醇硬脂酸单酯

探讨了以负载型对甲苯磺酸为催化剂合成乙二醇硬脂酸单酯的工艺。研究了醇酸摩尔比、催化剂用量、带水剂用量、反应时间等因素对硬脂酸转化率的影响。结果表明,合成乙二醇硬脂酸酯优化条件是:n(乙二醇)∶n(硬脂酸)=3.5∶1,催化剂用量为硬脂酸的物质的量的2.8%,带水剂甲苯的用量为硬酯酸质量的30%,反应时间150min,在此条件下,酸的转化率可达97.82%。     

阳离子交换树脂催化合成草酸葑醇酯

阳离子交换树脂作为绿色环保型催化剂广泛应用于有机化合物的合成,通过催化反应,以葑醇和草酸为原料,合成草酸葑醇酯。考察催化剂类型、催化剂用量、反应温度、反应时间以及原料物质的量比对葑醇酯化反应的影响,通过单因素实验确定了酯化反应的最佳条件:催化剂为阳离子交换树脂NKC-9,催化剂用量为葑醇质量的50%,反应温度55℃,反应时间96 h,n(草酸)∶n(葑醇)=4∶1。在该条件下,葑醇平均转化率为92.06%,草酸葑醇酯平均选择性为93.51%,平均收率为86.07%。催化剂重复使用7次后,葑醇转化率为87.15%,草酸葑醇酯选择性为89.44%,收率为77.95%。NKC-9催化剂可以取代酰氯法合成草酸葑醇酯,具有环保和经济等优点。     

阳离子交换树脂催化合成阿魏酸乙酯

以乙醇和阿魏酸为原料,强酸性阳离子交换树脂为催化剂,直接酯化合成了阿魏酸乙酯,考察了树脂类型、催化剂用量、物质的量比、反应时间、催化剂重复使用性等因素对反应的影响。确定了最佳反应条件为:m(树脂)/m(阿魏酸)=0.12,n(乙醇)∶n(阿魏酸)=6∶1,加热回流反应7 h。在最佳反应条件下,阿魏酸转化率为83.4%,产品收率为78.1%。732型树脂催化剂重复使用4次,阿魏酸转化率不低于81%,收率不低于75%。     

油脂甘油醇解法合成硬脂酸单甘酯合成条件研究

硬脂酸单甘酯(glycerol monostearate,GM)是一种重要的多元醇型非离子表面活性剂。油脂甘油醇解法是制备单硬脂酸甘油酯最重要的工业方法,在油脂醇解反应中,脂肪酰基在油脂分子和加入的游离甘油分子之间重新排列,生成单甘酯和二甘酯。研究油脂甘油醇解法的合成条件对产物单甘脂含量的影响,对企业通过技术改进以提高生产效益、降低能耗和节约生产成本,具有积极的指导作用。本文通过对投料比、催化剂种类、催化剂量、反应温度、反应时长5个因素进行实验和分析,发现:(1)酯交换法合成单酯,反应转化率随甘油∶氢化油的摩尔比先增大后减小。当甘油∶氢化油的摩尔比为2∶1时,粗酯中单甘酯含量最高;(2)催化剂采用Na OH的催化活性相对较高,其次,Ka OH的催化活性也比较高;(3)酯交换法合成单酯,反应转化率随Na OH加入量的增加先增大后减小,催化剂占氢化油质量的0.4%时粗酯中单甘酯含量最大;(4)酯交换法合成单酯,反应转化率随反应温度的升高先增大后减小,235℃时单甘酯含量最大;(5)酯交换法合成单酯,单甘酯反应转化率随反应时长的延长先增大后减小,2.5 h时单甘酯含量最大;(6)通过正交考察酯交换法合成单酯最佳反应条件为催化剂采用Na OH,添加量为氢化油质量的0.4%、反应温度235℃、反应时长2 h,其反应单酯含量可以达到40.2%。     

V-Cu氧化物催化碳酸二甲酯与苯酚酯交换反应

研究了一系列钒-金属复合氧化物对碳酸二甲酯(DMC)和苯酚酯交换合成碳酸二苯酯(DPC)的催化性能,实验结果表明,钒-铜复合氧化物是较好的酯交换合成DPC的催化剂。考察了V/Cu摩尔比,催化剂用量,DMC用量和反应时间对酯交换反应的影响,得到较佳的反应条件： n(V):n(Cu) = 4:1,苯酚用量0.16 mol,V-Cu复合氧化物催化剂的用量为苯酚用量的3.1%（质量比）, n(DMC) : n(苯酚) = 1.5 :1,反应时间9～15 h。在此条件下反应9 h,苯酚的转化率为41.9%,甲基苯基碳酸酯(MPC)及DPC的总收率为40.3%。催化剂重复使用4次后苯酚转化率从41.9%降到29.1%,多次重复使用后的催化剂在空气氛中焙烧即可再生,再生催化剂的催化性能几乎和新鲜催化剂相当,苯酚转化率达到39.8%。     

活性白土催化合成三甘醇二异辛酸酯

以三甘醇和异辛酸为原料,在活性白土的作用下,催化酯化合成三甘醇二异辛酸酯。考察酸醇物质的量比、反应时间、催化剂用量、带水剂用量等条件对酯化反应的影响,确定最佳合成工艺条件。合成三甘醇二异辛酸酯的最佳条件为酸醇物质的量比为4∶1,反应时间为5h,催化剂用量为8%,带水剂用量为33%,三甘醇转化率可达93.45%。催化剂不经任何处理重复使用3次后,三甘醇转化率有所下降,但催化剂经过再生后,三甘醇转化率可达93.2%,产品经气相色谱分析三甘醇二异辛酸酯含量为77.01%,三甘醇一异辛酸酯含量是14.48%。     

甘油缩丙酮的合成研究

以甘油与丙酮为原料,以氨基磺酸为催化剂,合成甘油缩丙酮。考察了原料物质的量比、反应时间和催化剂用量等因素对产品收率的影响。最佳工艺条件为:甘油用量为7 mL(约0.1 mol),n(丙酮)∶n(甘油)=4.0,氨基磺酸用量为甘油质量的4%,石油醚与甘油体积相同,回流反应4.5 h。该条件下,产品收率可高于86%。     

Ca and Zn mixed oxide as a heterogeneous base catalyst for transesterification of palm kernel oil

Transesterification of palm kernel oil with methanol over mixed oxides of Ca and Zn has been investigated batchwise at 60 °C and 1 atm. CaO·ZnO catalysts were prepared via a conventional co-precipitation of the corresponding mixed metal nitrate solution in the presence of a soluble carbonate salt at near neutral conditions. The catalysts were characterized by using techniques of X-ray diffraction (XRD), scanning electron microscope (SEM), and thermogravimetric analysis (TGA). The results indicated that the mixed oxides possess relatively small particle sizes and high surface areas, compared to pure CaO and ZnO. Moreover, the combination of Ca and Zn reduced the calcination temperature required for decomposition of metal carbonate precipitates to active oxides. Influences of Ca/Zn atomic ratio in the mixed oxide catalyst, catalyst amount, methanol/oil molar ratio, reaction time, and water amount on the methyl ester (ME) content were studied. Under the suitable transesterification conditions at 60 °C (catalyst amount = 10 wt.%, methanol/oil molar ratio = 30, reaction time = 1 h), the ME content of >94% can be achieved over CaO·ZnO catalyst with the Ca/Zn ratio of 0.25. The mixed oxide can be also applied to transesterification of palm olein, soybean, and sunflower oils. Furthermore, the effects of different regeneration methods on the reusability of CaO·ZnO catalyst were investigated.     

Transesterification of edible and non-edible oils over basic solid Mg/Zr catalysts

A series of Mg–Zr catalysts with varying Mg to Zr ratios was prepared by co-precipitation method. These catalysts were characterized by BET surface area, X-ray diffraction, X-ray photo electron spectroscopy and temperature programmed desorption of CO₂. The catalytic activity of these catalysts was evaluated for the room temperature transesterification of both edible and non-edible oils to their corresponding fatty acid methyl esters. The catalyst with Mg/Zr (2:1 wt./wt.%) exhibited exceptional activity towards transesterification reaction within short reaction time. The effects of different reaction parameters such as catalyst to oil mass ratio, reaction temperature, reaction time and methanol to oil molar ratio were studied to optimize the reaction conditions. The reasons for the observed activity of these catalysts are discussed in terms of their basicity and other physico-chemical properties.     

Methane Dehydroaromatization on Mo/HMCM-22 Catalysts: Effect of SiO2/Al2O3 Ratio of HMCM-22 Zeolite Supports

Zn/I₂ was found to be a practical and effective catalyst for the transesterification of soybean oil with methanol. A study for optimizing the reaction conditions such as the molar ratio of methanol to oil, the reaction time and the catalyst amount, was performed. The highest conversion of 96% was obtained under the optimum conditions. Further, the effect of free fatty acids and water in the soybean oil on the catalytic activity of the catalysts was also investigated.     

Heterogeneous Catalyst of Mixed K Compounds/Ca‐Al‐Graphite Oxide for the Transesterification of Soybean Oil to Biodiesel

A novel heterogeneous solid base catalyst was prepared by loading of Ca‐Al‐graphite oxide with mixed potassium salts and applied in the transesterification of soybean oil with methanol to produce biodiesel. The catalysts were characterized by Hammett indicators, X‐ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive X‐ray spectrometry, and transmission electron microscopy. The effects of the methanol‐to‐oil molar ratio, catalyst amount, reaction temperature, stirring rate, and reaction time were investigated to optimize the transesterification reaction conditions. Moreover, the prepared catalyst retains its activity after being used for four cycles. In particular, the solid base catalyst can be effectively and easily separated from the reaction system, which may provide significant benefits for the development of an environmentally benign and continuous process for preparing biodiesel.     

Ba–ZnO catalysts for soybean oil transesterification

The transesterification of soybean oil to biodiesel using Ba–ZnO as a solid catalyst was investigated. The Ba–ZnO sample with loading of 2.5 mmol/g Ba on ZnO and being calcined at 873 K for 5 h, was found to be the optimum catalyst, which could exhibit the highest basicity and the best catalytic activity for the reaction. When the transesterification reaction was carried out at reflux of methanol (338 K), with a 12:1 molar ratio of methanol to oil and a catalyst amount of 6 wt.%, the conversion of soybean oil was 95.8%. Furthermore, XRD, XPS, DTA–TG and the Hammett indicator method were employed for the catalyst characterizations, and the relation between the catalytic efficiency and the basicity of the catalysts was also discussed.     

硝酸镧改性钙镁锌催化剂制备生物柴油

通过掺杂不同比例的硝酸镧实现对钙镁锌三金属氧化物固体碱催化剂的改性,对改性催化剂用于制备生物柴油的工艺条件的了优化,并通过SEM的方法对改性催化剂的表面结构进行表征。结果表明硝酸镧的加入可以降低钙镁锌三金属氧化物固体碱催化剂最适催化温度并减少催化剂用量。添加3%(质量分数)的硝酸镧的改性钙镁锌体系催化剂,在反应温度为50℃时,醇油摩尔比为15∶1,反应时间为1h时,生物柴油产率可达到86.8%。这种改性催化剂更适于工业化应用。     

Marble slurry derived hydroxyapatite as heterogeneous catalyst for biodiesel production from soybean oil

In this study, utilization of waste marble slurry (MS) as an eco‐friendly and low‐cost heterogeneous catalyst is introduced for biodiesel production from soybean oil. Catalytic transesterification reaction was done to convert biodiesel from soybean oil using Marble slurry (MS) derived calcined marble slurry (CMS), and hydroxyapatite (HAP) as a heterogeneous catalyst. Marble slurry derived catalysts were characterized by XRD, FTIR, SEM, and TGA with elemental analysis. Hammett indicator method and ion exchange method were also used to verify catalytic activities of the catalysts. The HAP provided the better biodiesel yield of 94 ± 1 % with the highest basicity (13.30 mmol/g) and basic strength than CMS under optimized reaction conditions: reaction temperature 65 °C; reaction time 3 h; methanol/oil molar ratio 9:1; and catalyst concentration 6 wt%. Reusability tests provide confirmation about the stability of the catalyst and slight fluctuations in catalytic activity and biodiesel yield when used up to five runs.

     

Transesterification of karanja (Pongamia pinnata) oil by solid basic catalysts

The transesterification of karanja oil with methanol was carried out using solid basic catalysts. Alkali metal‐impregnated calcium oxide catalysts, due to their strong basicity, catalyze the transesterification of triacylglycerols. The alkali metal (Li, Na, K)‐doped calcium oxide catalysts were prepared and used for the transesterification of karanja oil containing 0.48–5.75% of free fatty acids (FFA). The reaction conditions, such as catalyst concentration, reaction temperature and molar ratio of methanol/oil, were optimized with the solid basic Li/CaO catalyst. This catalyst, at a concentration of 2 wt‐%, resulted in 94.9 wt‐% of methyl esters in 8 h at a reaction temperature of 65 °C and a 12 : 1 molar ratio of methanol to oil, during methanolysis of karanja oil having 1.45% FFA. The yield of methyl esters decreased from 94.9 to 90.3 wt‐% when the FFA content of karanja oil was increased from 0.48 to 5.75%. The performance of this catalyst was not significantly affected in the presence of a high FFA content up to 5.75%. The catalytic activities of Na/CaO and K/CaO were also studied at the optimized reaction conditions. In these two cases, the reaction initially proceeds slowly, however, leading to similar yields as in the case of Li/CaO after 8 h of reaction time. The purified karanja methyl esters have an acid value of 0.36 mg KOH/g and an ester content of 98.6 wt‐%, which satisfy the American as well as the European specifications for biodiesel in terms of acid value and ester content.     

Biodiesel production from soybean oil and methanol using hydrotalcites as catalyst

Esters of fatty acids, derived from vegetable oils or animal fats, and known as biodiesel, are a promising alternative diesel fuel regarding the limited resources of fossil fuels and the environmental concerns. In this work, methanolysis of soybean oil was investigated using Mg-Al hydrotalcites as heterogeneous catalyst, evaluating the effect of Mg/Al ratio on the basicity and catalytic activity for biodiesel production. The catalysts were prepared with Al/(Mg + Al) molar ratios of 0.20, 0.25 and 0.33, and characterized by X-ray diffraction (XRD), textural analysis (BET method) and temperature-programmed desorption of CO₂ (CO₂-TPD). When the reaction was carried out at 230 °C with a methanol:soybean oil molar ratio of 13:1, a reaction time of 1 h and a catalyst loading of 5 wt.%, the oil conversion was 90% for the sample with Al/(Mg + Al) ratio of 0.33. This sample was the only one to show basic sites of medium strength. We also investigated the reuse of this catalyst, the effect of calcination temperature and made a comparison between refined and acidic oil.     

分子筛微波辐射负载CaO催化合成生物柴油

研究微波辐射法制备固体碱催化剂CaO/NaY在合成生物柴油中的应用。结果表明,该催化剂在醇油摩尔比9∶1,催化剂质量分数3%,反应温度65℃,反应时间3 h等条件下,以精制大豆油为原料制备的生物柴油得率可达95%;而以酸值(以KOH计)为4 mg/g和含水质量分数为1.5%的油脂为原料,生物柴油得率可分别达到92.4%和84.8%。催化剂结构表征表明:微波辐射改善了CaO在载体NaY上的分散,其总碱量(H-27)达到3.798mmol/g,是一种固体超强碱。