Alkali Catalysis of Different Vegetable Oils for Comparisons of Their Biodiesel Productivity

The main advantages of biodiesel are its biodegradability, renewablity, improved nontoxic exhaust emissions and unnecessary alteration of common diesel engines. Today, biodiesel is produced by catalysis of inorganic acids, alkali and free or immobilized lipases with vegetable oil and short chain alcohols. Alkali and acidic catalysts are the most using catalysts for production of biodiesel because of their higher reaction yield and rate. In this study, we have comprised biodiesel productivity of different vegetable oils like sunflower, safflower, canola, soybean, olive, hazelnut, corn oils and waste sunflower oils by alkali catalysis. The transesterification of oils were performed by using NaOCH3 as catalyst at 25°C and at 100°C for 1 h. A defined amount of methanol as 6/1 molar ratio to oil was premixed with the metallic sodium. The amount of metallic sodium in methanol was 1.6 w% of oil mass for all of the crude oils/frying oil. Optimum reaction temperature was found as 25°C. TLC (Thin Layer Choromatography) image and GC (Gas Choromatography) results demonstrates that the dominant fatty acid in safflower, soy bean, sunflower, canola, corn and waste sunflower oil esters was linoleic acid (18:2). Besides it was oleic acid (18:1) for the olive and hazelnut oil esters. When biodiesel productivities of eight different oils were compared, similar results were obtained.

DICP Symposium (I) on Catalysis: Future Directions of Catalysis Science and Technology October 16-18, 2003, Dalian, China

Introduction and Invitation DICP Symposium is a special series of interna-tional conference named after the Dalian Instituteof Chemical Physics (DICP). The DICP Symposiumwas founded with the purpose to promote the interna-tional communication and collaboration between theDICP and the international scientific community, to

Role of Microstructure and Spectrum Features on the Catalysis Effect of Ce1-x(Nd0.5Eu0.5)xO2-δSolid Solutions

Nanosized Ce^1-x）（Nd^0.5）Eu^0.5））xO^2-δ） solid solutions（x = 0.00-0.20） were synthesized by means of hydrothermal method.Then the solid solutions were ball milled with Mg2Ni and Ni powders for 20 h to get the Mg2Ni–Ni–5 mol% Ce^1-x）（Nd^0.5）Eu^0.5））xO^2-δ） composites.The structures and spectrum characteristics of the Ce^1-x）（Nd^0.5）Eu^0.5））xO^2-δ） solid solutions catalysts were analyzed systemically.XRD results showed that the doped samples exhibited single phase of CeO2 fluorite structure.The cell parameters and cell volumes were increased with increasing the doped content.Raman spectrum revealed that the peak position of F^2g mode shift to higher wavenumbers and the peak corresponding to oxygen vacancies were observed distinctly for the doped samples.UV-Vis technique indicated that the absorption peaks of Eu^3＋ and Nd^3＋ ions appeared; the bandgap energy was decreased linearly.The electrochemical and kinetic properties of the Mg2Ni–Ni–5 mol% Ce1-x（Nd0.5Eu0.5xO2-δ composites were measured.The maximum discharge capacity was increased from 722.3 mA h/g for x = 0.00 to 819.7 mA h/g for x = 0.16,and the cycle stability S20 increased from 25.0%（x = 0.00） to 42.2%（x = 0.20）.The kinetic measurement proved that the catalytic activity of composite surfaces and the hydrogen diffusion rate were improved for the composites with doped catalysts,especially for the composites with x = 0.16 and x = 0.20.The catalysis mechanism was analyzed from the point of microstructure and spectrum features of the Ce1-x（Nd0.5Eu0.5）xO2-δ solid solutions.

K_2CO_3 catalysis on the reactivity of top charged coke and stamp charged coke

The catalysis of K2CO3 on the reactivity of top charged coke and stamp charged coke from Pansteel in China was studied. The coke reaction index of the stamp charged coke was 1%-2% higher than that of the top charged coke. Under the catalysis of K2CO3, the coke reaction index of both cokes approximately increased by 4%, 6%, 10% and 6% at 900, 1000, 1100 and 1200℃, respectively. The reactivity of the K-enriched stamp charged coke was 1%-2% higher than that of the K-enriched top charged coke below 1100℃. However, only negligible differences were found in the temperature zone between 1100 and 1200℃. Scanning electron microscopy images illustrated that pores in the top charged coke were smaller and equally distributed, while relatively more big pores exist non-homogenously in stamp charged coke. Due to the different processes in production, the stamp charged coke was more porous and most of the pores tended to be applanate. Cracks were observed in the microstructure of the stamp charged coke during the carbon solution reaction, implying the inferior quality of the stamp charged coke to the top charged coke at high temperature. Diffusion of K during the carbon solution reaction was studied by the energy dispersive spectrometry. It is found that K gradually spreads into the center of lumpy coke with the rising of temperature and is equally distributed on the edges of pores at 1200℃. Besides, oxidation reactions of functional groups become faster with the catalysis of K.content

碱催化降解法制备抗癌活性化合物20(S)-原人参二醇

通过碱催化降解制备了与植物体内结构一致且具有抗癌活性的人参皂苷元20(S)原人参二醇,并对其进行分离及结构表征.将西洋参茎叶总皂苷和强碱溶于高沸点有机溶剂中,在常压和高温条件下进行降解.通过正交试验确定了制备20(S)原人参二醇的最佳降解条件,并将降解物经萃取、柱层析及重结晶等方法分离得到20(S)原人参二醇.按西洋参茎叶总皂苷计,20(S)原人参二醇产率为5.01%,纯度为98.56%.通过理化性质和光谱分析可确认该化合物为20(S)原人参二醇.所制备的20(S)原人参二醇具有产率和纯度高及成本低等特点.

碱处理HZSM-5催化纤维素热裂解制备芳烃

使用不同浓度的NaOH溶液(0.2~1.0mol/L)对不同硅铝比的HZSM-5沸石进行碱处理制备多级孔HZSM-5,研究了NaOH浓度对碱处理制备多级孔HZSM-5的影响规律以及多级孔HZSM-5在纤维素催化热裂解中的催化性能。采用N2吸附-脱附、XRD、TEM和NH_3-TPD对催化剂进行表征:XRD结果显示HZSM-5碱处理后,多级孔HZSM-5依然有MFI结构特征峰;N_2吸附-脱附和TEM表征结果表明碱处理后的ZSM-5晶体内有明显的介孔孔道,形成多级孔结构;NH3-TPD结果表明随着NaOH浓度的增加,多级孔HZSM-5的强酸量呈现先增加后减少的趋势,在0.4mol/L处达到最高值。在微型裂解仪与气相色谱-质谱联用装置中研究多级孔HZSM-5对纤维素催化热裂解制备芳烃的催化性能,结果显示硅铝比为25、38、50的HZSM-5芳烃产率分别从碱处理前的33.5%、35.6%和32.2%,最高增加至37.1%、38.5%和34.0%(0.4mol/L NaOH碱处理);焦炭产率分别由碱处理前的33.1%、31.5%和33.8%降低至29.1%、25.8%和29.8%。结果表明,通过有效调控碱处理条件能够提高纤维素催化热裂解过程中的芳烃产率,同时降低焦炭产率。

碱金属改性对SAPO-34分子筛催化性能的影响

通过等体积浸渍法,制备得到碱金属(Li、Na、K、Rb、Cs)改性的SAPO-34催化剂。并在常压连续固定床反应器上评价了各催化剂的甲醇制低碳烯烃(MTO)的性能,同时对催化剂进行了XRD、FT-IR、NH3-TPD等表征分析。结果表明,碱金属负载量为2%时,除Cs离子改性的催化剂低碳烯烃的选择性和寿命有所降低外,其他碱金属离子改性的SAPO-34催化剂低碳烯烃的选择性和寿命都有了明显的提高,尤其是Li离子改性的催化剂乙烯+丙烯的选择性达77%左右,寿命相对延长了2.5倍;将该催化剂再生3次后乙烯、丙烯的选择性几乎保持不变。

α-己基肉桂醛的合成研究

以苯甲醛和辛醛为原料,固体NaOH为碱性催化剂,PEG-400为相转移催化剂,进行固-液相转移催化合成了α-己基肉桂醛.用单因素实验法考察了苯甲醛和辛醛的物料比、NaOH及PEG-400用量、反应温度和反应时间对产物产率的影响,得到了较优化的工艺条件:以甲醇和水为溶剂,苯甲醛和辛醛的物质的量比为1.0∶1.0,反应温度为60℃,反应时间为3～4 h,NaOH用量为25.0％和PEG-400用量为2.0％,最后通过减压蒸馏得到了纯度为93.5％的α-己基肉桂醛,产品产率为77.9％.并采用1H NMR、GC-MS及FT IR对产物结构进行了表征.

2,5-呋喃二甲酸二甲酯的绿色高效制备

为提高2,5-呋喃二甲酸二甲酯的产品收率,开发了一种生物质基聚酯单体2,5-呋喃二甲酸二甲酯(DMFDCA)高效绿色制备方法。在四丁基溴化铵(TBAB)的协同作用下,以MgO作为催化剂,在温和条件下催化2,5-呋喃二甲酸(FDCA)与碳酸二甲酯(DMC)反应合成DMFDCA并研究反应时间、反应温度、催化剂用量等因素对产率的影响,同时对催化剂进行了表征。结果表明:在反应温度为150℃,反应时间为6 h的条件下,DMFDCA的产率达到66.7%。此外,在循环反应5次后催化剂MgO仍保持较高的活性,DMFDCA的产率为61.3%,表明MgO在该反应体系下循环稳定性良好。最后,解析了催化剂催化效率下降的原因是催化剂表面晶格氧的缺失以及晶面暴露程度的减少。

助剂对Au/TS-1催化丙烯气相直接环氧化活性的影响

采用沉积-沉淀法制备了Au／TS-1催化剂，考察了碱金属和碱土金属助剂对Au／TS-1催化剂在H2与02同时存在条件下丙烯气相直接环氧化反应的影响。实验结果表明，添加助剂的Au／TS-1催化剂的活性均有所提高，且环氧丙烷（PO）的选择性保持在90％左右。当载体中n（Si）：n（Ti）=100时，Au／TS-1催化剂（Au质量分数为0．13％）上的PO生成速率为25g／（h·kg），而添加K的Au—K／TS—1催化剂（Au质量分数为0．08％，K质量分数为0．14％）上的PO生成速率为44g／（h·kg），活性提高了近80％。表征结果显示，加入碱金属使Au颗粒变小（粒径为1～2nm），分散更加均匀，从而提高了催化剂的丙烯环氧化活性；而加入碱土金属后，催化剂上的Au负载量增加，也使催化剂活性有所提高。

三氯化钛还原-重铬酸钾滴定法测定球团矿中TFe

采用碱混合熔剂熔融试样代替硫磷混酸冒烟溶解试样，熔融物以热水浸取盐酸酸化后，首先用tin将大部分Fe^3＋还原成Fe^2＋；然后用TiCl3还原剩余的Fe^3＋，以钨酸钠做指示剂指示还原终点，即当Fe^3＋定量还原为Fe^2＋后，过量一滴TiCl3溶液，可使作为指示剂的六价钨（无色）还原成蓝色的钨化合物，故溶液呈蓝色，俗称“钨蓝”。过量的TiCl3可在硫酸铜的催化下，借水中的溶解氧和空气中的游离氧氧化使钨蓝色泽褪去，从而消除过量的TiCl3还原剂的影响。在硫磷混酸介质中，以二苯胺磺酸钠为指示剂，用重铬酸钾标准溶液滴定TFe量，分析结果令人满意。该法测定TFe的绝对误差小于0．15％，避免了用重铬酸钾氧化褪去钨蓝色泽时易引入的误差。

金属氯化物催化葡萄糖制备5-羟甲基糠醛

用金属氯化物做催化剂,碱金属卤化物做助剂,催化葡萄糖脱水制备5-羟甲基糠醛(5-HMF).在原料与催化剂的质量比为10∶1,原料与助催化剂的质量比为1∶1的情况下,考察金属氯化物、助剂、溶剂、温度、时间对5-HMF收率的影响.结果显示:Al Cl3做催化剂、Na I做助剂、溶剂为N,N-二甲基乙酰胺(DMAC)、反应温度为130℃、反应时间为15 min时5-HMF收率可达30.6%.

1-氨基-1-肼基-2,2-二硝基乙烯碱金属盐的制备及对改性双基推进剂主组分热分解的催化作用

1-氨基-1-肼基-2,2-二硝基乙烯(AHDNE)与氢氧化钾或碳酸铯反应得到相应的碱金属盐AHDNE-K和AHDNE-Cs。通过元素分析和红外光谱对其进行结构表征;采用单晶X射线衍射分析法测定了AHDNE-K的单晶结构,DSC技术研究了两种金属盐对3种改性双基推进剂主组分HMX、RDX和NC/NG热分解的影响。结果表明,AHDNE-K对NC/NG有明显的催化效果,使分解温度降低了约24℃,能量增加了1 316 J.g-1。

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.

Catalytic effect of alkali carbonates on CO_2 gasification of Pingshuo coal

Na2CO3, Li2CO3, and K2CO3 were used as additives to Pingshuo （PS） coal that was subsequently gasified under a CO2 stream. The catalytic gasification of coal samples by CO2 in the presence single or mixed alkali carbonates was investigated by thermogravimetric analysis. The experimental results indicate that the catalytic effect of Li2CO3 is significantly larger than that of Na2CO3 or K2CO3. The catalytic effect of the mixed, bi-metal carbonate containing Li2C03 and Na2C03, or Li2CO3, and K2C03, is related to the compo- sition of the catalyst and the proportion of the two components. The bi-metal carbonates having a mole ratio of 9：1 （lri：x） has the largest catalytic effect for PS coal gasification. A synergistic effect between Li and K, or Na, carbonate appears at temperatures greater than 1300 K. An un-reacted shrinking core model is suitable for kinetic analysis of catalytic gasification of coal samples in the presence of alkali carbonates. It is inappropriate, however, to evaluate the catalytic effect only by the activation energy obtained from the kinetic calculations.

Effect of alkali metal ions on the formation mechanism of HCN during pyridine pyrolysis

The catalytic effects of alkali metal ions(Na^(+)and K^(+))on NO_(x)precursor formation during coal pyrolysis were investigated using the N-containing compound pyridine as a model compound.Density functional theory calculations at the B3LYP/6-31G(d,p)level of theory were conducted to elucidate the mechanism of pyridine pyrolysis and the pathways for HCN formation.The calculation results indicate that Na^(+)and K^(+)have distinct influences on different pyrolysis reactions;these alkali metal ions facilitate the initial hydrogen transfer from C_(1)to N and C_(2),whereas they hinder the other hydrogen migration reactions.Both Na^(+)and K^(+)significantly reduce the activation energies for C–C bond breakage and triple-bond formation,whereas they increase the activation energies for the isomerization reactions.The different effects essentially result from the distinct charge distributions induced by the two ions.Due to the distinct influences on the different reactions,the rate-determining steps are modulated,affecting the competitiveness of the different possible pathways of HCN formation.The formation of HCN from pyridine is promoted in the presence of Na^(+)and K^(+)because all the overall activation energies are decreased for different pathways.The calculation results agree well with previous experimental studies.Thus,the findings offer a new and promising approach to reveal the formation mechanism of NO_(x)and facilitate the control of NO_(x)for coal utilization.

Preparation of SO_4^(2-)/TiO_2-La_2O_3 solid superacid and its catalytic activities in acetalation and ketalation

SO4^2- / TiO2-La2O3, a novel solid superacid, was prepared and its catalytic activities at different synthetic conditions are discussed with esterification of n-butanoic acid and n-butyl alcohol as probing reaction. The optimum conditions have also been found, mole ratio of n（La^3＋）：n（Ti^4＋） is 1：34, the soaked consistency of H2SO4 is 0.8 tool/L, the soaked time of HESO4 is 24 h, the calcining temperature is 480 ℃, the calcining time is 3 h. Then it was applied in the catalytic synthesis often important ketals and acetals as catalyst and revealed high catalytic activity. Under these conditions on which the molar ratio of aldehyde/ketone to glycol is l： 1.5, the mass ratio of the catalyst used in the reactants is 0.5%, and the reaction time is 1.0 h, the yields of ketals and acetals can reach 41.4%-95.8%.

Effects of Zr/Ti molar ratio in SO_4^(2-)/ZrO_(2-)TiO_2 calcined at different temperatures on its surface properties and glucose reactivity in near-critical methanol

Effects of Zr/Ti molar ratio in SO42-/ZrO2-TiO2 solid acid catalyst calcined at different temperatures on its surface properties and catalytic activity were thoroughly investigated in this paper. The physicochemical characteristics of prepared samples were determined by N2 adsorptiondesorption, XRD, NH3-TPD and XPS techniques, respectively. It was found that the crystallization temperature of the samples increased after the combination of ZrO2 and TiO2; and phase transformations from the anatase to the rutile of TiO2 species and the tetragonal to the monoclinic of ZrO2 species were effectively suppressed at higher temperature. The sample with a Zr/Ti molar ratio of 3/1 calcined at 450℃ showed the highest surface area and the most acid sites among all the tested samples. The acid site densities of samples were relatively closed to each other if they were calcined at the same temperature, however, decreased with the calcination temperature. The result indicates that the sulfur content in samples is a crucial factor to control the acid site density. Calcining the sample at 650℃ and higher temperatures resulted in a significant desorption of sulfate ion on the samples. The synthesized samples were evaluated as a potential catalyst for glucose conversion under the near-critical methanol conditions （200℃/4 MPa）. The results suggested that the relatively weaker acid sites of the catalyst were more favorable for the accumulation of methyl glucosides, while the moderate acid sites were responsible for the formation of methyl levulinate. The catalytic activity for methyl levulinate production almost increases linearly with the catalyst acid site density. The catalyst deactivation is due to the loss of sulfate ion and the two catalysts with Zr/Ti molar ratios of 3/1 and 1/3 could effectively alleviate the deactivation caused by sulfate solution in the reaction medium and can be reused after calcination with the reuse rate of over 90% in terms of the methyl levulinate selectivity.

LRG1 promotes corneal angiogenesis and lymphangiogenesis in a corneal alkali burn mouse model

AIM:To investigate the potential effect and mechanism of leucine-richα-2-glycoprotein-1(LRG1)on corneal angiogenesis and lymphangiogenesis.METHODS:Corneal neovascularization and lymphatics were induced by establishing alkali burn mouse model.Immunofluorescence staining was performed to detect the location of LRG1 in cornea tissues and to verify the source of LRG1-positive cells.Corneal whole-mount staining for CD31(a panendothelial cell marker)and lymphatic endothelial hyluronan receptor-1(LYVE-1;lymphatic marker)was performed to detect the growth of blood and lymphatic vessels after local application of exogenous LRG1 protein or LRG1 si RNA.In addition,expressions of the proangiogenic vascular endothelial growth factor(VEGF)related proteins were detected using Western blot analysis.RESULTS:LRG1 was dramatically increased in alkali burned corneal stroma in both the limbal and central areas.LRG1-positive cells in the corneal stroma were mainly derived from Vimentin-positive cells.Local application ofexogenous LRG1 protein not only aggravated angiogenesis but also lymphangiogenesis significantly(P<0.01).LRG1 group upregulated the levels of VEGF and the vascular endothelial growth factor receptor(VEGFR)family when compared with the phosphate-buffered saline(PBS)control group.We also found that LRG1-specific si RNA could suppress corneal angiogenesis and lymphangiogenesis when compared with the scramble si RNA-treated group(P<0.01).CONCLUSION:LRG1 can facilitate corneal angiogenesis and lymphangiogenesis through heightening the stromal expression of VEGF-A,B,C,D and VEGFR-1,2,3;LRG1-specific si RNA can suppress corneal angiogenesis and lymphangiogenesis in corneal alkali burn mice.

布朗斯特酸性离子液体[DC2O2IM][p-CH3PhSO3]催化Biginelli三组分反应的研究

本文报道了布朗斯特酸性离子液体1,3-二羧甲基咪唑对甲苯磺酸盐作为一种绿色、环境友好的催化剂,成功地催化Biginelli三组分反应合成了一系列3,4-二氢嘧啶-2(1H)-酮或硫酮化合物。该方法具有条件温和、产率高、反应时间短的优点。此外,催化剂离子液体可循环使用五次且催化活性没有明显降低。