纤维素乙醇产业化

由于能发挥缓解能源紧张、减少环境污染、促进农村发展等重要作用,利用年产量巨大的植物纤维资源,生产可再生性液体替代燃料乙醇的技术受到了巨大的关注,成为工业生物技术的研究热点.酶法生产纤维素乙醇面临多种困难:纤维素原料比重轻,收集运输不便;原料结构复杂,需要深度预处理;纤维素酶系的酶解效率有待提高;半纤维素中的木糖难以发酵转化为乙醇等.经过多年研究,新技术已经取得重大进展,开始接近实用化.紧迫的社会需求正在迫使国内外政府和企业界大量投资,开展纤维素乙醇的中试研究和试生产,力求在短时期内克服上述难点,尽快实现产业化.充分利用植物纤维资源中的多种组分,联合生产乙醇和部分高值产品的生物精练技术,是实现纤维素乙醇产业化的重要突破口和必然途径.玉米芯生物精练生产乙醇和木糖相关产品的技术正在进行产业化.本文综述了纤维素乙醇产业化的研究进展并做了展望.     

纤维素乙醇产业化

由于能发挥缓解能源紧张、减少环境污染、促进农村发展等重要作用,利用年产量巨大的植物纤维资源,生产可再生性液体替代燃料乙醇的技术受到了巨大的关注,成为工业生物技术的研究热点。酶法生产纤维素乙醇面临多种困难:纤维素原料比重轻,收集运输不便;原料结构复杂,需要深度预处理;纤维素酶系的酶解效率有待提高;半纤维素中的木糖难以发酵转化为乙醇等。经过多年研究,新技术已经取得重大进展,开始接近实用化。紧迫的社会需求正在迫使国内外政府和企业界大量投资,开展纤维素乙醇的中试研究和试生产,力求在短时期内克服上述难点,尽快实现产业化。充分利用植物纤维资源中的多种组分,联合生产乙醇和部分高值产品的生物精练技术,是实现纤维素乙醇产业化的重要突破口和必然途径。玉米芯生物精练生产乙醇和木糖相关产品的技术正在进行产业化。本文综述了纤维素乙醇产业化的研究进展并做了展望。     

秸秆发酵燃料乙醇关键问题及其进展

利用木质纤维素原料生产燃料乙醇是国际公认的难题.本文从秸秆原料组分不均一性出发,分析了秸秆难以高值化原因;进一步分析了秸秆酶解发酵燃料乙醇的关键问题,介绍了有关秸秆原料预处理、纤维素酶生产、秸秆酶解发酵乙醇和产业化示范工程等的进展.秸秆酶解发酵燃料乙醇产业化示范工程具有自主知识产权,为实现我国秸秆转化燃料乙醇的规模化、产业化、低成本生产奠定了基础.     

秸秆发酵燃料乙醇关键问题及其进展

利用木质纤维素原料生产燃料乙醇是国际公认的难题。本文从秸秆原料组分不均一性出发,分析了秸秆难以高值化原因;进一步分析了秸秆酶解发酵燃料乙醇的关键问题,介绍了有关秸秆原料预处理、纤维素酶生产、秸秆酶解发酵乙醇和产业化示范工程等的进展。秸秆酶解发酵燃料乙醇产业化示范工程具有自主知识产权,为实现我国秸秆转化燃料乙醇的规模化、产业化、低成本生产奠定了基础。     

秸秆发酵燃料乙醇关键问题及其进展

利用木质纤维素原料生产燃料乙醇是国际公认的难题.本文从秸秆原料组分不均一性出发,分析了秸秆难以高值化原因;进一步分析了秸秆酶解发酵燃料乙醇的关键问题,介绍了有关秸秆原料预处理、纤维素酶生产、秸秆酶解发酵乙醇和产业化示范工程等的进展.秸秆酶解发酵燃料乙醇产业化示范工程具有自主知识产权,为实现我国秸秆转化燃料乙醇的规模化、产业化、低成本生产奠定了基础.     

中国纤维素乙醇技术的研究进展

中国面临着严重的能源短缺和环境污染问题,中国政府正在局部几个省份内政策性鼓励燃料乙醇生产和使用.尽管当前主要是用玉米和谷物作为生产乙醇的原料,然而中国具有大量潜在的低成本的纤维素生物质原料,可以极大地扩大乙醇的产量,降低原料成本.近20年来,由于技术的革命性进步,已使得纤维素乙醇的生产成本从4美元/加仑以上,降低至约1.2-1.5美元/加仑.其中,每吨生物质约44美元.因此,目前乙醇掺汽油具有十分强的市场竞争力.已有几个公司正在建造首批商业纤维素乙醇工厂,虽然这些刚起步的小型设施在合理利用和管理上风险较小,但规模经济需要较大型工厂.尽管配送生物质原料的成本会随需求的增加而增加,但在乙醇生产基础上的生物精炼技术的发展,尤其是化工产品和动力的协同生产,将会使全过程的经济可行性大大提高.进一步深入的基础研究,将解决低成本下实现纤维素的完全利用,以确保在无政策性补贴的前提下,真正使纤维素乙醇成为具有市场竞争力的低成本纯液体燃料.     

以制浆造纸产业为平台的生物炼制新模式

本文通过分析木质生物质炼制与制浆造纸工业之间的关系,提出以制浆造纸产业为平台的生物炼制模式。在蒸煮制浆前,增加对原料预抽提处理,提取半纤维素等成分用于生产乙醇燃料和（或）其他化工化学品,抽提残渣则采用传统化学法、高得率法或有机溶剂法制浆,实现植物纤维原料多组分分离综合利用。该模式给制浆造纸产业提供一条可持续发展的新思路。     

纤维素制取乙醇技术

以纤维素为原料生产燃料乙醇由于其原料来源广泛及环保效益良好而被认为是最有前景的生产燃料乙醇的方法之一.以纤维素为原料生产乙醇主要包括水解和发酵两个转化过程.本文介绍了纤维素生产燃料乙醇的原理及工艺过程,同时讨论了各工艺过程需要解决的关键技术问题,分析了过程的经济性,最后介绍了国内外的应用现状,展望了纤维素生产燃料乙醇的产业化前景.     

纤维素制取乙醇技术

以纤维素为原料生产燃料乙醇由于其原料来源广泛及环保效益良好而被认为是最有前景的生产燃料乙醇的方法之一.以纤维素为原料生产乙醇主要包括水解和发酵两个转化过程.本文介绍了纤维素生产燃料乙醇的原理及工艺过程,同时讨论了各工艺过程需要解决的关键技术问题,分析了过程的经济性,最后介绍了国内外的应用现状,展望了纤维素生产燃料乙醇的产业化前景.     

基于纤维小体展示技术的酿酒酵母纤维素乙醇研究进展

利用联合生物加工工艺生产第二代燃料乙醇(纤维素乙醇)是国内外的研究热点.前期的研究结果表明,酿酒酵母分泌或展示非复合型纤维素酶体系的应用效果并不理想,而复合型纤维素酶体系(即纤维小体)因对纤维素的降解能力比非复合型纤维素酶体系更强,所以其在酿酒酵母细胞表面的组装研究受到越来越多的关注.目前,单支架和双支架纤维小体在酵母细胞表面的完全自组装以及多细胞协同参与的非完全自组装均已实现.纤维小体展示型酿酒酵母已能直接利用结晶型纤维素发酵生产乙醇,但由于降解模块的结构缺陷,纤维素乙醇的产量仍然偏低.本文对纤维小体的酵母展示技术及其在纤维素乙醇发酵中的应用研究进行了论述,并对该领域的发展方向进行了展望.     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.