纤维乙醇制乙烯的研究

采用改性HZSM-5催化剂对纤维乙醇脱水制乙烯进行研究,主要考察反应温度、底物加载量以及催化剂负荷性能等对乙烯产率的影响。结果发现：反应温度235℃、纤维乙醇质量分数为40%～95%乙醇质量空速不超过1.7 h-1时乙烯收率达98%以上。     

响应面法优化Zn-Mn-Co/HZSM-5催化乙醇脱水制乙烯

采用响应面法研究温度、乙醇浓度、质量空速对锌、锰、钴改性的HZSM-5催化乙醇脱水制备乙烯过程中乙烯收率的影响。结果表明反应温度对乙烯收率影响最大,并且各因素之间存在交互作用。用响应面方法确定乙醇脱水制备乙烯的最佳工艺条件是：温度261.3 ℃,乙醇浓度34.4％,质量空速1.18 h?1,在该条件下乙烯收率达到98.69％。     

催化山梨醇脱水制备异山梨醇的固体酸催化剂

为提高目标产物异山梨醇的产率,考察多种固体酸催化剂催化山梨醇脱水的反应性能。结果表明:催化剂酸性与其催化性能之间有密切联系,酸性较强的H3PO4/Nb2O5催化剂显示出比其他催化剂更优异的催化性能。对磷酸负载量进行优化后,在n(P)/n(Nb)为0.8的H3PO4/Nb2O5催化剂上得到了100%的山梨醇转化率和63%的异山梨醇选择性。     

脂肪酶YCJ01拆分对位取代α-苯乙醇

利用脂肪酶YCJ01催化拆分对位取代α-苯乙醇衍生物。以异丙醚为反应介质,采用乙酸乙烯酯作为酰基供体,对180 mmol/L的1-(4-甲基苯基)乙醇进行选择性酯化,脂肪酶粗酶粉添加量为5 g/L,50℃反应21 h后,底物转化率可达49.96%,对映体过量值e.e.s、e.e.p值分别为97.1%和97.2%,对映体选择性E200;同样,对1-(4-甲氧基苯基)乙醇进行选择性酯化,酰基供体为丁酸乙烯酯,底物浓度150 mmol/L,脂肪酶粗酶粉添加量为2.5g/L,30℃反应12 h后,底物转化率为49.8%,e.e.s、e.e.p值分别为97.7%和98.4%,对映体选择性E200,显示了很好的手性拆分效果。     

枯草芽胞杆菌PnbA酯酶选择性拆分制备l-薄荷醇

利用重组大肠杆菌表达来源于枯草芽胞杆菌CICC 20034中的PnbA酯酶,不对称催化水解dl-薄荷醇丙酸酯制备l-薄荷醇。考察助溶剂种类、助溶剂添加浓度、温度、催化剂用量、底物浓度以及p H等对反应的影响。结果表明:添加25%(体积分数)助溶剂乙醇可显著提升该酯酶对l-薄荷醇的立体选择性,对映选择率(E)由2.4提高到99.43,为不加乙醇条件下的40倍。酶催化最佳条件:25%乙醇作为助溶剂,反应温度37℃,缓冲液为0.1 mol/L Tris-HCl(p H 8.0)并保持p H 8.0反应条件,底物量50 mmol/L,反应体系中酶的添加量750 U/m L,在此条件下,酶促反应30 min后,l-薄荷醇转化率可达34%,产物光学纯度对映体过量值(e.e._p)达95%。     

Au/C催化剂的制备及其对木质素模型化合物的催化氧化研究

以酸处理后的活性炭为载体,采用浸渍法制备了活性炭负载的Au催化剂,研究了该催化剂对木质素模型化合物2-(2-甲氧基苯氧基)-1-苯基乙醇的催化氧化降解反应。结果表明,以甲醇为溶剂,氧气做氧化剂,当反应温度为150℃,反应压力为1.0 MP时,Au/C催化剂能较好的降解木质素模型化合物,转化率达到88%,所得主要产物为愈创木酚,并给出了其可能的催化氧化机理。     

生物乙烯研究进展

介绍了生物乙烯的背景和发展概况,总结了乙醇脱水反应的机理和所用的各类催化剂,分析了生物乙烯产业化中需要解决的关键技术问题,并指出发展生物乙烯有着光明的前景,对石油路线代替战略有着重要的意义.     

NKC-9干氢型树脂催化合成油酸甲酯

采用强酸性阳离子交换树脂作催化剂,对油酸和甲醇反应合成油酸甲酯的工艺进行研究。分别筛选了4种型号的树脂,其中以NKC-9干氢型树脂催化效果最好。考察了酸醇摩尔比、反应温度、催化剂用量、脱水剂用量、反应时间和催化剂重复使用性等因素对转化率的影响。结果表明:反应的适宜条件为酸醇摩尔比1∶2,反应温度70℃,催化剂用量为油酸质量的50%,脱水剂无水CaCl2用量为催化剂用量的10%,反应时间2 h。在此条件下,转化率可达93.85%。催化剂重复使用6次后转换率仍保持在90%以上。研究显示,采用NKC-9干氢型树脂催化合成油酸甲酯具有良好的工业应用潜力。     

光敏核不育水稻幼穗的乙烯生成与育性转换

研究了在不同光温组合下光敏核不育水稻（ＰＧＭＲ）农垦５８５（ＮＫ５８Ｓ）及普通水稻品种农垦５８（ＮＫ５８Ｂ）的幼穗乙烯生物合成变化及其与育性表达的关系。结果表明ＮＫ５８Ｓ幼穗乙烯生成受光周期和温度的共同调节,而光周期对ＮＫ５８Ｂ幼穗乙烯生成无明显影响。ＮＫ５８Ｓ幼穗乙烯生成的变化与育性转换光温作用模式完全吻合。其幼穗乙烯释放速率（ＥＲＲ）与花粉可育度（ｌｎｙ）呈极显著负相关。用ＡＶＧ抑制乙烯生成可使ＮＫ５８Ｓ（ＬＤ）不育性明显逆转,而用ＡＣＣ促进乙烯生成又可急剧降低ＮＫ５８Ｓ（ＳＤ）的可育水平。表明幼穗乙烯生成与ＰＧＭＲ育性表达密切相关,乙烯参与育性转换的调控并可能起着重要作用。     

非水相酶促合成癸酸偏甘油酯的研究

对无溶剂非水相中癸酸与甘油的酶促酯化反应进行了研究,发现Pseudomonas fluoresces脂肪酶（PFL）、Mucor miehei脂肪酶（MML）和Candida antarictica脂肪酶（CAL）均有较好的催化活性。CAL酶促转化癸酸的最适反应条件为：60℃,加酶量为20～100u/g,初始加水量为甘油质量的12%。CAL的1,3位置专一性在最终产物中未表达。CAL酶催化剂的失活主要与机械磨损有关,反应5批次后酶活残留量为96.4%。敞开物系、真空脱水或分子筛脱水均为有效脱水方式。敞开物系中反应物量比不影响平衡转化率而会影响单甘酯平衡产率。用碳酸氢钠水溶液萃取可有效脱除产品中的残余癸酸,终产品酸价为0.68mg KOH/g。提高甘油比例并使用非脱水原料,无外加水结合部分流加癸酸的工艺,可以减少减压脱水或敞开反应的时间,5h后癸酸最高转化率可达96.9%。      

Selective dehydration of bio-ethanol to ethylene catalyzed by lanthanum-phosphorous-modified HZSM-5: influence of the fusel

Bio-ethanol dehydration to ethylene is an attractive alternative to oil-based ethylene. The influence of fusel, main byproducts in the fermentation process of bio-ethanol production, on the bio-ethanol dehydration should not be ignored. We studied the catalytic dehydration of bio-ethanol to ethylene over parent and modified HZSM-5 at 250°C, with weight hourly space velocity (WHSV) equal to 2.0/h. The influences of a series of fusel, such as isopropanol, isobutanol and isopentanol, on the ethanol dehydration over the catalysts were investigated. The 0.5%La-2%PHZSM-5 catalyst exhibited higher ethanol conversion (100%), ethylene selectivity (99%), and especially enhanced stability (more than 70 h) than the parent and other modified HZSM-5. We demonstrated that the introduction of lanthanum and phosphorous to HZSM-5 could weaken the negative influence of fusel on the formation of ethylene. The physicochemical properties of the catalysts were characterized by ammonia temperature-programmed desorption (NH(3)-TPD), nitrogen adsorption and thermogravimetry (TG)/differential thermogravimetry (DTG)/differential thermal analysis (DTA) (TG/DTG/DTA) techniques. The results indicated that the introduction of lanthanum and phosphorous to HZSM-5 could inhibit the formation of coking during the ethanol dehydration to ethylene in the presence of fusel. The development of an efficient catalyst is one of the key technologies for the industrialization of bio-ethylene.     

Catalytic upgrading of bio-oil by HZSM-5 in sub- and super-critical ethanol

The pyrolysis bio-oil from rice husk was upgraded in sub- and super-critical ethanol using HZSM-5 as catalyst. The results showed that super-critical upgrading process performed more effectively than sub-critical upgrading process. Acidic HZSM-5 facilitates esterification in super-critical ethanol to convert acids contained in crude bio-oil into various kinds of esters. Stronger acidic HZSM-5 (low Si/Al ratio) can facilitate cracking of heavy components of crude bio-oil more effectively in super-critical upgrading process. The residue of distillated upgraded bio-oil from super-critical upgrading process decreased evidently, compared with that of distillated crude bio-oil. This work proved that crude bio-oil can be effectively upgraded in super-critical upgrading process with the aid of acidic catalyst.     

Effect of catalyst additives on the production of biofuels from palm oil cracking in a transport riser reactor

Catalytic cracking of crude palm oil (CPO) and used palm oil (UPO) were studied in a transport riser reactor for the production of biofuels at a reaction temperature of 450 °C, with residence time of 20 s and catalyst-to-oil ratio (CTO) of 5 g g^?1. The effect of HZSM-5 (differrent Si/Al ratios), beta zeolite, SBA-15 and AlSBA-15 were studied as physically mixed additives with cracking catalyst Rare earth-Y (REY). REY catalyst alone gave 75.8 wt% conversion with 34.5 wt% of gasoline fraction yield using CPO, whereas with UPO, the conversion was 70.9 wt% with gasoline fraction yield of 33.0 wt%. HZSM-5, beta zeolite, SBA-15 and AlSBA-15 as additives with REY increased the conversion and the yield of organic liquid product. The transport riser reactor can be used for the continuous production of biofuels from cracking of CPO and UPO over REY catalyst.     

Removal of free fatty acid in waste frying oil by esterification with methanol on zeolite catalysts

The removal of free fatty acid (FFA) in waste frying oil by esterification with methanol was conducted using various zeolite catalysts. The ZSM-5 (MFI), mordenite (MOR), faujasite (FAU), beta (BEA) zeolites, and silicalite were employed with different Si/Al molar ratio in the reaction. The effects of acidic properties and pore structure of the zeolite catalysts were discussed relating to the conversion of the FFA. The MFI zeolite induced an improvement of the removal efficiency of FFA by cracking to the FFA in its pore structure due to its narrow pore mouth. The catalytic activity for FFA removal was lowered with decreasing of acid strength of the zeolites. The strong acid sites of zeolites induced the high conversion of FFA comparatively. The acid strength and pore structure of acidic zeolites affected the catalytic activity in FFA removal.     

Selective conversion of bio-oil to light olefins: controlling catalytic cracking for maximum olefins

Light olefins are the basic building blocks for the petrochemical industry. In this work, selective production of light olefins from catalytic cracking of bio-oil was performed by using the La/HZSM-5 catalyst. With a nearly complete conversion of bio-oil, the maximum yield reached 0.28±0.02 kg olefins/(kg bio-oil), which was close to that from methanol. Addition of La into zeolite efficiently changed the total acid amount of HZSM-5, especially the acid distribution among the strong, medium and weak acid sites. A moderate increase of the number of the medium acid sites effectively enhanced the olefins selectivity and improved the catalyst stability. The comparison between the catalytic cracking and pyrolysis of bio-oil was studied. The mechanism of the conversion of bio-oil to light olefins was also discussed.     

Effect of Si/Al ratio on tetralin adsorption on Y zeolite: a DFT study

Probing the adsorption of tetralin on zeolite is of prime scientific and industrial importance with the aim to upgrade the industrial process of tetralin cracking. In this work, the effect of Si/Al ratio ranging from 12 to 39 on tetralin adsorption property on Y zeolite is studied by DFT calculations. Tetralin adsorption on Y zeolite corresponds to a π-stacking adsorption mechanism between double bonds of aromatic ring and Brønsted acid sites. Therefore, the number of Brønsted acid sites influences the adsorption properties. Lower Si/Al ratio with more Brønsted acid sites interacting with the aromatic ring of tetralin leads to a higher adsorption energy. Furthermore, the charge and frontier molecular orbital analysis are also performed to understand the influence of Si/Al ratio on adsorption performance. Y zeolite with lower Si/Al ratio shows larger charge difference values and lower HOMO–LUMO gap, which directly manifests the stronger adsorption ability of tetralin and indicates bigger possibility of reacting.     

Concentration of docosahexaenoic and eicosapentaenoic acids by enzymatic alcoholysis with different acyl-acceptors

The aim of this work was to produce docosahexaenoic (DHA) and eicosapentaenoic acid (EPA) enriched acylglycerols by alcoholysis of tuna and sardine oils, respectively, using isobutanol and 1-butanol as acyl-acceptors. The alcoholysis reactions were catalyzed by lipases Lipozyme® TL IM from Thermomyces lanuginosus and lipase QLG® from Alcaligenes sp., because these lipases have shown selectivity towards DHA and EPA, respectively. Studies were made to determine the influence of reaction time, alcohol/oil molar ratio, lipase amount and temperature. In the optimized conditions for the alcoholysis of tuna and sardine oils catalyzed by Lipozyme TL IM and lipase QLG, respectively, the DHA and EPA contents were trebled (from 22 to 69% for DHA, and from 19 to 61% for EPA). The stability of both lipases was also determined. Although Lipozyme TL IM is much more stable in isobutanol than in ethanol, with the former the conversion attained after four reaction cycles was about 40% of the initial conversion. In similar conditions, the conversion obtained with lipase QLG was about 88% of the initial conversion. In addition, the separation of DHA enriched acylglycerols and isobutyl esters from an alcoholysis reaction was studied by liquid–liquid fractionation using the ethanol–water–hexane biphasic system. The DHA enriched acylglycerols obtained were 97.6% pure (64.4% DHA).     

Production of biofuel from waste cooking palm oil using nanocrystalline zeolite as catalyst: process optimization studies

The catalytic cracking of waste cooking palm oil to biofuel was studied over different types of nano-crystalline zeolite catalysts in a fixed bed reactor. The effect of reaction temperature (400-500 °C), catalyst-to-oil ratio (6-14) and catalyst pore size of different nanocrystalline zeolites (0.54-0.80 nm) were studied over the conversion of waste cooking palm oil, yields of Organic Liquid Product (OLP) and gasoline fraction in the OLP following central composite design (CCD). The response surface methodology was used to determine the optimum value of the operating variables for maximum conversion as well as maximum yield of OLP and gasoline fraction, respectively. The optimum reaction temperature of 458 °C with oil/catalyst ratio=6 over the nanocrystalline zeolite Y with pore size of 0.67 nm gave 86.4 wt% oil conversion, 46.5 wt% OLP yield and 33.5 wt% gasoline fraction yield, respectively. The experimental results were in agreement with the simulated values within an experimental error of less than 5%.