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1.
甘油是产量巨大的生物质.将之转化为有用化合物的研究,有重要的工业应用价值.甘油的氢解可生成一系列的C-3醇,如正丙醇、异丙醇、1,2-丙二醇以及1,3-丙二醇等.其中,1,3-丙二醇是合成聚对苯二甲酸丙二醇酯(PPT)的重要有机中间体.因此,选择性氢解甘油合成1,3-丙二醇,是一个重要的研究课题.最近,在研究Pt/WO_3/Zr O_2催化下的甘油氢解反应时发现,通过调控催化剂载体中氧化钨含量,可以调节催化剂的酸碱度,从而在保持较高1,3-丙二醇选择性的同时,显著提高反应的转化率.这一技术提高了合成效率,有潜在的工业应用价值.  相似文献   

2.
刘宏娟  杜伟  刘德华 《化学进展》2007,19(7):1185-1189
生物柴油作为可再生的清洁能源,已在美国、欧盟等多个国家和地区推行使用.在生物柴油的生产过程中,最高可得到约10%的副产物甘油,副产物甘油的去向将成为生物柴油大规模产业化发展所面临的严峻问题.1,3-丙二醇是一种重要的化工原料,作为合成新型聚酯PTT的原料,1,3-丙二醇已引起人们的广泛关注.以生物柴油副产物甘油为原料耦合生产1,3-丙二醇,不仅解决了生物柴油副产物甘油的出路问题,同时降低了1,3-丙二醇的生产成本.本文详细介绍了生物柴油及1,3-丙二醇生产技术及联产工艺的研究进展,并对其应用前景进行了展望.  相似文献   

3.
生物柴油作为可再生的清洁能源,已在美国、欧盟等多个国家和地区推行使用.在生物柴油的生产过程中,最高可得到约10%的副产物甘油,副产物甘油的去向将成为生物柴油大规模产业化发展所面临的严峻问题.1,3-丙二醇是一种重要的化工原料,作为合成新型聚酯PTT的原料,1,3-丙二醇已引起人们的广泛关注.以生物柴油副产物甘油为原料耦合生产1,3-丙二醇,不仅解决了生物柴油副产物甘油的出路问题,同时降低了1,3-丙二醇的生产成本.本文详细介绍了生物柴油及1,3-丙二醇生产技术及联产工艺的研究进展,并对其应用前景进行了展望.  相似文献   

4.
甘油作为生物柴油产业的副产物大量过剩,通过甘油氢解制备具有高附加值的丙二醇既符合原子经济的原则,又具有重要的学术意义和应用价值.尤其是选择氢解制得1,3-丙二醇,因其产物在新型聚酯材料合成中不可替代的作用而备受关注,被认为是最具工业应用潜力的甘油转化工艺之一.目前,可高选择性制得1,3-丙二醇的催化剂体系主要是为铱-铼催化剂和铂-钨催化剂两类.前期工作表明,氧化钨担载的铂单原子/准单原子催化剂(Pt/WOx)具有优异的低压活性(1 MPa氢气)和1,3-丙二醇时空收率.然而在该温和条件下,催化产物仍然以过度氢解的产物正丙醇为主.一般来讲,引入助剂可以通过改变活性组分的电子结构、覆盖不利反应位点、调变载体表面化学性质等来改变催化剂的催化活性、选择性和稳定性.我们以单原子/准单原子催化剂Pt/WOx和担载型催化剂Pt/WOx/Al2O3为催化剂母体,引入过渡金属和贵金属助剂,考察助剂对氢解反应活性和选择性的影响,并对比有无氧化铝载体时助剂对反应活性的影响.对于Pt/WOx体系,La和Fe的引入有助于甘油转化率和1,3-丙二醇选择性的提高,同时也明显地提高了催化剂的稳定性.其中0.1% La是最佳引入量.然而,对于担载型催化剂Pt/WOx/Al2O3,La的引入在提高1,3-丙二醇选择性的同时,甘油的转化率也有一定程度下降.但由于Pt/WOx/Al2O3催化剂的本征活性较高,通过加入助剂提高1,3-丙二醇的选择性在实际应用中更为重要.表征分析表明,无论对于Pt/WOx还是Pt/WOx/Al2O3催化剂,大部分的La都在Pt颗粒上;同时La的引入提高了催化剂的酸量.在贵金属助剂中,Ru,Ir改性的Pt/WOx和Pt/WOx/Al2O3催化剂上,1,3-丙二醇的收率均有所降低,Ru助剂的降低幅度较小.相反,助剂Rh对Pt/WOx和Pt/WOx/Al2O3催化剂上反应性能的影响截然不同:Rh/Pt/WOx催化剂上1,3-丙二醇的收率从13.1%降到8.7%,Rh/Pt/WOx/Al2O3的1,3-丙二醇收率从31.5%略升到32.4%.另外,由于前期研究表明助剂铝的担载顺序对催化活性有重要影响,因此我们对铂、钨、铝的担载顺序进行了考察.研究表明,在活性组分铂上担载铝或钨物种对催化活性有一定程度的抑制;催化剂体系中钨的含量直接影响甘油的转化率和产物的选择性;含量过少时,甘油转化率极低并以1,2-丙二醇为主要产物.虽然大部分助剂对铂-钨催化剂体系没有明显的促进作用,但是助剂的添加通常可以抑制活性组分的烧结、提高催化剂的稳定性;因此,我们筛选出的La,Fe,Re,Ru,Rh等助剂仍具有深入研究的价值和工业应用的潜力.  相似文献   

5.
生物柴油作为可再生的清洁能源,已在美国、欧盟等多个国家和地区推行使用。在生物柴油的生产过程中,最高可得到约10%的副产物甘油,副产物甘油的去向将成为生物柴油大规模产业化发展所面临的严峻问题。1,3-丙二醇是一种重要的化工原料,作为合成新型聚酯PTT的原料,1,3-丙二醇已引起人们的广泛关注。以生物柴油副产物甘油为原料耦合生产1,3-丙二醇,不仅解决了生物柴油副产物甘油的出路问题,同时降低了1,3-丙二醇的生产成本。本文详细介绍了生物柴油及1,3-丙二醇生产技术及联产工艺的研究进展,并对其应用前景进行了展望。  相似文献   

6.
甘油作为生物柴油产业的副产物大量过剩,通过甘油氢解制备具有高附加值的丙二醇既符合原子经济的原则,又具有重要的学术意义和应用价值.尤其是选择氢解制得1,3-丙二醇,因其产物在新型聚酯材料合成中不可替代的作用而备受关注,被认为是最具工业应用潜力的甘油转化工艺之一.目前,可高选择性制得1,3-丙二醇的催化剂体系主要是为铱-铼催化剂和铂-钨催化剂两类.前期工作表明,氧化钨担载的铂单原子/准单原子催化剂(Pt/WOx)具有优异的低压活性(1 MPa氢气)和1,3-丙二醇时空收率.然而在该温和条件下,催化产物仍然以过度氢解的产物正丙醇为主.一般来讲,引入助剂可以通过改变活性组分的电子结构、覆盖不利反应位点、调变载体表面化学性质等来改变催化剂的催化活性、选择性和稳定性.我们以单原子/准单原子催化剂Pt/WOx和担载型催化剂Pt/WOx/Al2O3为催化剂母体,引入过渡金属和贵金属助剂,考察助剂对氢解反应活性和选择性的影响,并对比有无氧化铝载体时助剂对反应活性的影响.对于Pt/WOx体系,La和Fe的引入有助于甘油转化率和1,3-丙二醇选择性的提高,同时也明显地提高了催化剂的稳定性.其中0.1%La是最佳引入量.然而,对于担载型催化剂Pt/WOx/Al2O3,La的引入在提高1,3-丙二醇选择性的同时,甘油的转化率也有一定程度下降.但由于Pt/WOx/Al2O3催化剂的本征活性较高,通过加入助剂提高1,3-丙二醇的选择性在实际应用中更为重要.表征分析表明,无论对于Pt/WOx还是Pt/WOx/Al2O3催化剂,大部分的La都在Pt颗粒上;同时La的引入提高了催化剂的酸量.在贵金属助剂中,Ru,Ir改性的Pt/WOx和Pt/WOx/Al2O3催化剂上,1,3-丙二醇的收率均有所降低,Ru助剂的降低幅度较小.相反,助剂Rh对Pt/WOx和Pt/WOx/Al2O3催化剂上反应性能的影响截然不同:Rh/Pt/WOx催化剂上1,3-丙二醇的收率从13.1%降到8.7%,Rh/Pt/WOx/Al2O3的1,3-丙二醇收率从31.5%略升到32.4%.另外,由于前期研究表明助剂铝的担载顺序对催化活性有重要影响,因此我们对铂、钨、铝的担载顺序进行了考察.研究表明,在活性组分铂上担载铝或钨物种对催化活性有一定程度的抑制;催化剂体系中钨的含量直接影响甘油的转化率和产物的选择性;含量过少时,甘油转化率极低并以1,2-丙二醇为主要产物.虽然大部分助剂对铂-钨催化剂体系没有明显的促进作用,但是助剂的添加通常可以抑制活性组分的烧结、提高催化剂的稳定性;因此,我们筛选出的La,Fe,Re,Ru,Rh等助剂仍具有深入研究的价值和工业应用的潜力.  相似文献   

7.
空气-乙炔火焰原子吸收光谱法测定铬,易受灵敏度低、基体干扰的限制。70年代中期有人提出应用表面活性剂之后,使这一测定得到了改善。本实验选用阴离子表面活性剂十二烷基硫酸钠(SLS)和非离子表面活性剂乙二醇辛基苯基酚(OP-10)、曲拉通X-100(Triton X-100)对铬的空气-乙炔火焰原子吸收光谱法的增感  相似文献   

8.
 考察了不同溶剂中 Pt/WO3/ZrO2 催化剂催化甘油加氢制 1,3-丙二醇的反应性能. 结果表明, 质子溶剂乙醇和水有利于甘油转化为 1,3-丙二醇. 含有乙醇或水的二元混合溶剂表现出明显的溶剂组分协同效应, 使用混合溶剂时 1,3-丙二醇选择性超过使用单一溶剂, 而且混合溶剂的组成对反应性能影响很大.  相似文献   

9.
生物转化生产1,3-丙二醇的研究进展   总被引:9,自引:0,他引:9  
综述了近几年生物转化生产1,3-丙二醇的研究进展,介绍了1,3-丙二醇工业生产的现状、生物转化的菌种及其生产能力、生物转化1,3-丙二醇的代谢途径、甘油的同底物发酵及基因工程对菌种的改造,展望了今后研究的发展方向。  相似文献   

10.
近年来,以生物质为基础的生物柴油得到了迅速发展,导致了粗甘油过剩.通过甘油选择性氢解制1,3-丙二醇,进而被用于合成高价值的聚对苯二甲酸丙二醇酯被认为是最具工业应用潜力的反应之一,对于提高生物柴油的利用效率有着极其重要的意义.但由于反应空间位阻和热力学上的限制给甘油氢解制1,3-丙二醇带来了很大的挑战,因此需要设计高活性的金属-酸双功能催化剂以降低甘油第二个C-O键断裂的活化能和减少其他副反应的发生.目前Pt-W和Ir-Re双功能催化剂可高选择性制得1,3-丙二醇,但仍需较严苛的反应条件实现对氢气的活化和解离.本课题组曾将准单原子/单原子Pt高度分散于具有大量氧空位和酸位点的WO_x载体上,十分有利于甘油选择性氢解制1,3-丙二醇反应;在Au-Pt/WO_x催化剂中添加Au可促进B酸产生,进而提高了甘油转化率和1,3-丙二醇的选择性.为了进一步研究Au对Pt/WO_x催化剂结构和催化性能的影响,本文利用CTAB辅助吸附法制备了Au/WO_3,再浸渍Pt制得Pt/Au/WO_3双金属催化剂.在甘油选择性氢解制1,3-丙二醇反应中,所制催化剂表现出比Au-Pt/WO_x更好的催化活性,1,3-丙二醇时空收率为0.078 g_(1,3-PDO)/(g_(cat)·h),是后者的1.95倍.值得一提的是,Au-Pt/WO_x催化剂在低压时活性较高,而Pt/Au/WO_3催化剂活性则在压力的升高而提高;另外反应温度的升高导致副产物正丙醇的选择性上升,1,3-丙二醇的选择性降低.因此,适宜的反应条件为155 ℃和5 MPa.与Pt/WO_3和Pt/WO_x相比,Pt/Au/WO_3表现出了更优异的催化性能,其1,3-丙二醇的时空收率是Pt/WO_3的2.36倍和Pt/WO_x的4倍.为了探究Au的掺入对Pt/WO_x催化剂性能的影响,通过XRD,TEM,H_2-TPR和XPS等技术对催化剂进行了深入表征.结果表明,与Pt/WO_3相比,Pt/Au/WO_3-600催化剂的XRD衍射峰向小角度偏移,其原因是Au3+离子半径(0.85?比W6+的(0.60?大,Au~(3+)以取代晶格W~(6+)形式进入WO_3晶格中;对H_2-TPR前300 ℃耗氢量的计算可知:Pt/WO_3可被还原至Pt/WO_2.96,而Pt/Au/WO_3可被还原至Pt/Au/WO_2.91.因此与Pt/WO_3相比,Pt/Au/WO_3表面氧空位更加丰富.TEM和XPS表征可知,添加0.1wt%Au后,促进了更低价态的Pt均匀分散在WO_3载体上,其平均粒径为2.36 nm.综上所述,Au的掺杂改变了Pt/Au/WO_3双金属催化剂的结构,不仅降低了Pt和W的还原温度,削弱了Pt和W之间的相互作用,也促进了更低价态的Pt均匀分散于WO_3载体上,使得Pt/Au/WO_3双金属催化剂在甘油氢解制1,3-丙二醇反应中具有更为优异的活性和产物选择性.该催化剂有望被广泛运用于其他生物质平台化合物加氢脱氧的反应中.  相似文献   

11.
The microbial production of 1,3-propanediol (1,3-PD) from raw glycerol, a byproduct of biodiesel production, is economically and environmentally advantageous. Although direct use of raw glycerol without any pretreatment is desirable, previous studies have reported that this could cause inhibition of microbial growth. In this study, we investigated the effects of raw glycerol type, different microorganisms, and pretreatment of raw glycerol on the production of 1,3-PD. Raw glycerol from waste vegetable-oil-based biodiesel production generally caused more inhibition of 1,3-PD production and microbial growth compared to raw glycerol from soybean-oil-based biodiesel production. In addition, two raw glycerol types produced from two biodiesel manufacturers using waste vegetable oil exhibited different 1,3-PD production behavior, partially due to different amounts of methanol included in the raw glycerol from the two biodiesel manufacturers. Klebsiella strains were generally resistant to all types of raw glycerol while the growth of Clostridium strains was variably inhibited depending on the type of raw glycerol. The 1,3-PD production of the Clostridium strains using acid-pretreated raw glycerol was significantly enhanced compared to that with raw glycerol, demonstrating the feasibility of using raw glycerol for 1,3-PD production by various microorganisms.  相似文献   

12.
1,3-Propanediol (1,3-PD) biosynthesis plays a key role in NADH consumption to regulate the intracellular reducing equivalent balance of Klebsiella pneumoniae. This study aimed to increase reducing equivalent for enhancing 1,3-PD production through cofermentation of glycerol and xylose. Adding xylose as cosubstrate resulted in more reducing equivalent generation and higher cell growth. In batch fermentation under microaerobic condition, the 1,3-PD concentration, conversion from glycerol, and biomass (OD(600)) relative to cofermentation were increased significantly by 9.1%, 20%, and 15.8%, respectively. The reducing equivalent (NADH) was increased by 1-3 mg/g (cell dry weight) compared with that from glycerol alone. Furthermore, 2,3-butannediol was also doubly produced as major byproduct. In fed-batch fermentation with xylose as cosubstrate, the final 1,3-PD concentration, conversion from glycerol, and productivity were improved evidently from 60.78 to 67.21 g/l, 0.52 to 0.63 mol/mol, and 1.64 to 1.82 g/l/h, respectively.  相似文献   

13.
The production of 1,3-propanediol (1,3-PD) was investigated with Klebsiella pneumoniae DSM 4799 using raw glycerol without purification obtained from a biodiesel production process. Fed-batch cultures with suspended cells revealed that 1,3-PD production was more effective when utilizing raw glycerol than pure glycerol (productivity after 47 h of fermentation, 0.84 g?L?1?h?1 versus 1.51 g?L?1?h?1 with pure and raw glycerol, respectively). In addition, more than 80 g/L of 1,3-PD was produced using raw glycerol; this is the highest 1,3-PD concentration reported thus far for K. pneumoniae using raw glycerol. Repeated fed-batch fermentation with cell immobilization in a fixed-bed reactor was performed to enhance 1,3-PD production. Production of 1,3-PD increased with the cycle number (1.06 g?L?1?h?1 versus 1.61 g?L?1?h?1 at the first and fourth cycle, respectively) due to successful cell immobilization. During 46 cycles of fed-batch fermentation taking place over 1,460 h, a stable and reproducible 1,3-PD production performance was observed with both pure and raw glycerol. Based on our results, repeated fed batch with immobilized cells is an efficient fermentor configuration, and raw glycerol can be utilized to produce 1,3-PD without inhibitory effects caused by accumulated impurities.  相似文献   

14.
This study investigated the biological conversion of crude glycerol generated from a commercial biodiesel production plant as a by-product to 1,3-propanediol (1,3-PD). Statistical analysis was employed to derive a statistical model for the individual and interactive effects of glycerol, (NH4)2SO4, trace elements, pH, and cultivation time on the four objectives: 1,3-PD concentration, yield, selectivity, and productivity. Optimum conditions for each objective with its maximum value were predicted by statistical optimization, and experiments under the optimum conditions verified the predictions. In addition, by systematic analysis of the values of four objectives, optimum conditions for 1,3-PD concentration (49.8 g/L initial glycerol, 4.0 g/L of (NH4)2SO4, 2.0 mL/L of trace element, pH 7.5, and 11.2 h of cultivation time) were determined to be the global optimum culture conditions for 1,3-PD production. Under these conditions, we could achieve high 1,3-PD yield (47.4%), 1,3-PD selectivity (88.8%), and 1,3-PD productivity (2.1/g/L/h) as well as high 1,3-PD concentration (23.6 g/L).  相似文献   

15.
During the fermentative production of 1, 3-propanediol (1,3-PD), the multiple product inhibitions cannot be negligible to accurately describe the kinetics of fermentation process. A kinetic model for fermentative production of 1,3-PD by Klebsiella pneumoniae HR526 with glycerol as carbon source under aerobic condition was proposed. The inhibitions of multiple products including 1,3-PD, 2, 3-butanediol (2,3-BD), acetate, and succinate were considered in the model. It was found that 1,3-PD, 2,3-BD, and acetate showed strong inhibitions to cell growth depending on their concentrations. The kinetic model was relatively accurate to predict the experimental data of batch, fed-batch, and continuous fermentations. The model thus can serve as a tool for further controlling and optimizing the fermentation process.  相似文献   

16.
Glycerol metabolism is a typical biological oxidoreductive reaction. 1,3-Propanediol (1,3-PD) is the final product of the reductive branch, while acetate, succinate, lactate, 2,3-butanediol (2,3-BD), and ethanol were produced in the oxidative branch. 2,3-BD, which has similar properties of high boiling point and water solubility with 1,3-PD, not only contests the carbon flow and NADH with 1,3-PD but also serves as an obstacle for obtaining high purity 1,3-PD in downstream processes. In this study, a 2,3-BD pathway-deficient mutant of Klebsiella oxytoca ZG36 was constructed by knocking out the budA gene of the wild-type strain M5al. The results of fed-batch fermentation by ZG36 indicated that the glycerol flux and the distribution of metabolites were altered in the K. oxytoca when the 2,3-BD pathway was blocked. No 2,3-BD was produced, and the activity of α-acetolactate decarboxylase (α-ALDC) can not be detected in the fermentation processes. The indexes of the 1,3-PD titer, the conversion from glycerol to 1,3-PD, and the productivity per cell dry weight (CDW) increased by 42%, 62%, and 46%, respectively, compared with the M5al, and the yield of the byproducts also increased obviously. The assay of the enzyme activities in the oxidative branch and the reductive branch of the glycerol metabolism, as well as the intracellular redox state, exposited the results logically.  相似文献   

17.
1,3-Propanediol (1,3-PD) has numerous applications from polymers to cosmetics, foods, lubricants, and medicines. Recently, there are strong industrial interests in a new kind of polyester, polytrimethylene terephthalate, with 1,3-PD as a monomer. This new polyester shows significant promise for use in carpeting and textiles. In this article we introduce a mild aerobic fermentation process using a strain screened from Klebsiella pneumoniae ATCC 25955, which is insensitive to oxygen, to produce 1,3-PD. We also describe a two-step fermentation process starting with glucose that was converted into glycerol with a glycerol-producing yeast, followed by K. pneumoniae that converts glycerol into 1,3-PD without intermediate isolation and purification of glycerol.  相似文献   

18.
1,3-Propanediol (1,3-PD) is an intermediate in chemical and polymer synthesis. We have previously expressed the genes of a biochemical pathway responsible for 1,3-PD production, thedha regulon ofKlebsiella pneumoniae, inEscherichia coli. An analysis of the maximum theoretical yield of 1,3-PD from glycerol indicates that the yield can be improved by the cofermentation of sugars, provided that kinetic constraints are overcome. The yield of 1,3-PD from glycerol was improved from 0.46 mol/mol with glycerol alone to 0.63 mol/mol with glucose cofermentation and 0.55 mol/mol with xylose cofermentation. The engineeredE. coli also provides a model system for the study of metabolic pathway engineering.  相似文献   

19.
Novel and selective microbial amperometric biosensors that use Gluconobacter oxydans cells to monitor the bacterial bioconversion of glycerol (Gly) to 1,3-propanediol (1,3-PD) are described. Two different mediators, ferricyanide and flexible polyvinylimidazole osmium functionalized polymer (Os-polymer), were employed to prepare two different microbial biosensors, both of which gave high detection performance. The good operational stabilities of both types of biosensor were underlined by the ability to detect 1,3-PD throughout 140 h of continuous operation. Both microbial biosensor systems showed excellent selectivity for 1,3-PD in the presence of a high excess of glycerol [selectivity ratios (1,3-PD/Gly) of 118 or 245 for the ferricyanide and Os-polymer systems, respectively]. Further, the robustness of each microbial biosensor was highlighted by the high reliability of 1,3-PD detection achieved (average RSD of standards <2%, and well below 4% for samples). The biosensor implementing the Os-polymer mediator exhibited high selectivity towards 1,3-PD detection and allowed moderate sample throughput (up to 12 h−1) when integrated into a flow system. This system was used to monitor the concentration of 1,3-PD during a real bioprocess. Results from biosensor assays of 1,3-PD in bioprocess samples taken throughout the fermentation were in a very good agreement with results obtained from reference HPLC assays (R 2 = 0.999).  相似文献   

20.
The metabolism of residual glycerol from biodiesel synthesis by Klebsiella pneumoniae BLh-1 was investigated in this study. Batch and fed-batch cultivations were performed in bioreactors under anaerobic and oxygen limitation conditions. Results of batch cultivations showed that the main product was 1,3-propanediol (1,3-PD) in both conditions, although the higher yields and productivities (0.46 mol mol?1 glycerol and 1.22 g?L?1?h?1, respectively) were obtained under anaerobic condition. Large amounts of ethanol were also produced under batch anaerobic condition, peaking at 12.30 g?L?1. Batch cultivations under oxygen limitation were characterized by faster growth kinetics, with higher biomass production but lower conversions of glycerol into 1,3-PD, with yields and productivities of 0.33 mol mol?1 glycerol and 0.99 g?L?1?h?1, respectively. The fed-batch cultivations were carried out in order to investigate the effects of feeding of raw glycerol on cells. Fed-batch under anaerobiosis showed that 1,3-PD and ethanol concentrations increased with the feeding rate, with maximal productions of 26.12 and 19.2 g?L?1, respectively. The oxygen limitation conditions diverted the bacterium metabolism to an elevated lactic acid formation, reaching 59 g?L?1 in higher feeding rates of glycerol, but lowering the production of ethanol.  相似文献   

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