催化挲報(bào)2010Chinese Journal of CatalysisVol 31 No 8文章編號(hào):0253-9837(2010)08-0928-國(guó)際版DOI:10.1016/S1872-2067(10)60104-0研究快訊:928-932磷化鎢催化轉(zhuǎn)化纖維素制乙二醇趙冠鴻2,鄭明遠(yuǎn)!,王愛(ài)琴!,張濤中國(guó)科學(xué)院大連化學(xué)物理研究所催化基礎(chǔ)國(guó)家重點(diǎn)實(shí)驗(yàn)室,遼寧大連1160232中國(guó)科學(xué)院研究生院,北京100049摘要:首次將磷化鎢(WP)催化劑應(yīng)用于纖維素的催化轉(zhuǎn)化反應(yīng).結(jié)果表明,與碳化鎢催化劑類似,WP催化劑也可高效地實(shí)現(xiàn)纖維素轉(zhuǎn)化.在H2初始?jí)毫?MPa,反應(yīng)溫度為245℃C時(shí),20%wPAC(活性炭)催化纖維素高選擇性地生成乙二醇,其收率為254mol%.2%鎳的加入使得該催化劑上乙二醇收率增至46.0mol1%,表明Ni與WP之間存在著明顯的協(xié)同作用關(guān)鍵詞:生物質(zhì);纖維素;磷化鎢;乙二醇中圖分類號(hào):O643文獻(xiàn)標(biāo)識(shí)碼:ACatalytic Conversion of Cellulose to Ethylene Glycol overTungsten Phosphide catalystsZHAo Guanhong, ZHENG Mingyuan, WANG Aiqin, ZHANG TaoState Key laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, ChinaGraduate University of Chinese Academy of Sciences, Beijing 100049, ChinaAbstract: Tungsten phosphide(wP) showed good activity in the selective conversion of cellulose to ethy lene glycol (EG). At a H2 initialpressure of 6 MPa and temperature of 245 C, EG yield reached 25. 4 mol% over 20%WP/AC (activated carbon)and 46.0 mol%over2%Ni-20%WP/AC, which demonstrated a remarkable synergy between Ni and WPKey words: biomass; cellulose; tungsten phosphide; ethylene glycol隨著化石能源的日漸枯竭和氣候環(huán)境的不斷惡于貴金屬的催化性質(zhì),將纖維素高選擇性地轉(zhuǎn)化為化,尋找清潔的替代能源成為人類的重要課題.由多元醇812.特別是在活性炭(AC)以及介孔炭負(fù)于生物質(zhì)具有碳平衡和可再生的優(yōu)點(diǎn),在新能源開(kāi)載的鎳-碳化鎢(W2C)催化劑上,纖維素高選擇性地發(fā)諸多途徑中,由生物質(zhì)轉(zhuǎn)化為能源化學(xué)品和大宗轉(zhuǎn)化為乙二醇(EG,其收率最高可達(dá)75wt%0.為平臺(tái)化合物備受人們關(guān)注.木質(zhì)纖維素是地球上最了進(jìn)一步闡明W2C在該反應(yīng)中獨(dú)特的催化作用,我豐富的生物質(zhì)資源,廣泛存在于各種農(nóng)業(yè)廢棄物中,們使用金屬Ni-W的組合代替Ni-W2C催化劑,發(fā)現(xiàn)但它的結(jié)構(gòu)致密復(fù)雜,因此,實(shí)現(xiàn)其高效、特別是高其仍可高選擇性地催化纖維素轉(zhuǎn)化為EG.而以選擇性轉(zhuǎn)化是一項(xiàng)極具挑戰(zhàn)性的課題.在各種可能磷化鎳為催化劑時(shí),纖維素主要轉(zhuǎn)化為山梨醇,而非的轉(zhuǎn)化途徑中”,利用固體催化劑催化轉(zhuǎn)化木質(zhì)纖乙二醇12.由此可見(jiàn),W物種在纖維素的CC鍵選維素具有反應(yīng)條件較溫和、選擇性高、催化劑易于擇性斷裂過(guò)程中起著非常關(guān)鍵的作用,而另一活性回收、環(huán)境友好等優(yōu)點(diǎn),因而成為近年來(lái)的研究熱點(diǎn)組分Ni則主要起加氫作用.為進(jìn)一步驗(yàn)證上述推之-【57斷,本文分別制備了AC和SiO2負(fù)載的磷化鎢本課題組曾利用過(guò)渡金屬碳化物和磷化物類似(WP)催化劑中國(guó)煤化工催化行為收稿日期:2010-06-24CNMHG聯(lián)系人:張濤.Tel:(0411)84379015;Fax:(0411)84685940;E-mai: taizhang @dicp.ac.cr基金來(lái)源:國(guó)家重點(diǎn)基礎(chǔ)研究發(fā)展計(jì)劃(973計(jì)劃,2009CB26102);國(guó)家自然科學(xué)基金(20903089,20773124)本文的英文電子版由 Elsevier出版社在 Science Direct上出版htp:ww. sciencedirect. com/science/journal18722067)www.chxb.cr趙冠鴻等:磷化鎢催化轉(zhuǎn)化纖維素制乙二醇929采用還原磷酸鹽法制備WP催化劑13.14.配制定濃度的偏鎢酸銨(AMT)和(NH4)2HPO4溶液,7 w,C等體積浸漬于AC( Norit,20-40目,比表面積709Ni?P20%WP/ACm2/g)或SO2(青島海洋化工廠,20-40目,比表面積L人人人455m2/g)上,于120℃C干燥12h,在H2中首先以會(huì)2%Ni-20%WP/A55C/min升至350°C,然后以1C/min升至850°C,并保持1h,H2空速(GHSV)為12000h1.還原20%WP/SIO結(jié)束后,待溫度降至室溫,通入1%02-99%N2混合氣鈍化4h.采用N(NO3)2,(NH4)2HPO4和AMT共浸60漬的方法制備Nⅰ-WP樣品,除了最終還原溫度為圖1不同磷化鎢催化劑的XRD譜650C之外,其他過(guò)程同上.制得的催化劑中WFig. 1. XRD patterns of different tungsten phosphide catalystsNi的理論含量分別為20wt%和2wt%使用PW3040/60 X Pert Pro( PANalytical)型見(jiàn),20%WPAC催化劑上出現(xiàn)典型的WP特征峰以Ⅹ射線衍射儀對(duì)催化劑物相進(jìn)行分析.催化劑的及少量的W2C晶相.這是由于在wP高溫還原制CO化學(xué)吸附實(shí)驗(yàn)在法國(guó) Seteram公司的BT2.15型備過(guò)程中,炭載體的碳熱還原作用使催化劑中形成微量熱量計(jì)上進(jìn)行5.測(cè)試前,催化劑在H2中于了W2C物相.而在20%WPSO2催化劑上,只觀察650℃C原位還原1h.催化劑的透射電鏡(TEM)表到一個(gè)很微弱的wP特征峰,這可能是由于WP高征在JEM-2000EX型透射電子顯微鏡上進(jìn)行.纖維度分散于SO2載體上.CO化學(xué)吸附實(shí)驗(yàn)表明,素催化轉(zhuǎn)化反應(yīng)在100m1不銹鋼高壓釜(Par儀器20% WP/SiO2上的CO吸附量為18.3μmol/g,而公司)中進(jìn)行.加入0.5g微晶纖維素、0.15g催化20%WP/AC上僅為83μmol/g這進(jìn)一步表明前者劑和50ml去離子水,攪拌速率為1000rmin,H2初的活性組分分散度更高.TEM結(jié)果(未示出)表明始?jí)毫?MPa(室溫下).在245℃C反應(yīng)30min. WP/SIO2樣品的WP粒徑明顯小于wP/AC反應(yīng)后液體產(chǎn)物用液相色譜儀分析.有機(jī)總碳由2%N20%WPAC催化劑主要晶相仍為WP,同時(shí)還Elementar Liqui TOC型總碳測(cè)定儀測(cè)定.反應(yīng)前后存在少量的W2C和Ni2P物相催化劑上金屬流失量由 IRIS Intrepid Il XSP型電各催化劑纖維素催化轉(zhuǎn)化反應(yīng)結(jié)果見(jiàn)表1.由感耦合等離子體發(fā)射光譜儀測(cè)得.氣相產(chǎn)物由氣相表可見(jiàn),在各WP催化劑上,纖維素反應(yīng)30min后色譜儀分析.反應(yīng)轉(zhuǎn)化率由反應(yīng)前后纖維素質(zhì)量變均完全轉(zhuǎn)化,其中,20%WPAC催化劑上所得的各化求得5.產(chǎn)物收率以反應(yīng)產(chǎn)物與投入釜內(nèi)纖維素種多元醇產(chǎn)物中,EG的收率最高,為254mol%,而的各自C的摩爾比計(jì)算12六元醇收率則僅為2.3mol%.這與我們?cè)缜皥?bào)道的圖1為不同磷化鎢催化劑的XRD譜.由圖可纖維素在W2CAC催化劑上反應(yīng)結(jié)果十分類似9表1不同催化劑上纖維素的轉(zhuǎn)化率及多元醇的產(chǎn)率Table 1 Results of cellulose conversion and polyol yields over the catalystsYield (mol/%)CatalyConversion(%) Conversion(%)Glycerol EG 1, 2-PG Sorbitol Mannitol Erythritol COz CO86.525.480.561.70.220%WP/AC2.120%WP/AC2%Ni-20%WP/AC87.2946.0640.80.030%NI/AC+20%WP/AC0.8中國(guó)煤化工CNMHG20%WP/AC in the 2nd run. 20%WP/AC in the 3rd run ' Cellulose conversion calculated bycelulose velue and after reactioncEllulose conversion calculated by organic carbon in liquid products divided by total carbon of cellulose put into the reactorG--Ethylene glycol; PG--Propylene glycol930催化學(xué)報(bào)Chin.J.Cua1,2010,31:928932由于20%WPAC催化劑制備過(guò)程中載體AC的碳ICP測(cè)定結(jié)果顯示,反應(yīng)過(guò)程中催化劑中的W流失熱還原作用而使催化劑中出現(xiàn)少量W2C,這可能對(duì)了52wt%.因而,我們推測(cè),催化劑活性的下降與EG的生成起到重要的催化作用.為排除這種影響,W的流失有很大的關(guān)系.另外,催化劑表面的部分本文考察了20% WP/SiO2催化劑的反應(yīng)性能.結(jié)果氧化也可能是失活原因之顯示,該催化劑性能與WPAC非常類似,纖維素主在纖維素轉(zhuǎn)化為多元醇的過(guò)程中,催化劑的加要轉(zhuǎn)化為EG,收率為250mo%這表明WP確實(shí)氫能力至關(guān)重要10.因此,本文利用Ni來(lái)修飾可直接催化纖維素轉(zhuǎn)化為EG相比于我們最近所WP催化劑,以形成更多的加氫活性中心.CO化學(xué)報(bào)道的磷化鎳催化劑12,兩者雖然同樣是磷化物,吸附測(cè)量結(jié)果顯示,Ni的添加使得20%WP/AC催但在纖維素轉(zhuǎn)化反應(yīng)中生成的產(chǎn)物卻明顯不同.纖化劑上CO吸附量由8.3μmolg增至11.9μmol/g維素在磷化鎳催化劑上高選擇性地生成山梨醇,收纖維素催化轉(zhuǎn)化反應(yīng)結(jié)果表明,Ni的添加使得催化率達(dá)484mol%,而在WP催化劑上得到的主要是劑上EG產(chǎn)率顯著增至460mol%.當(dāng)將10%Ni/AC小分子產(chǎn)物EG.結(jié)合我們前期對(duì)W2C以及金屬W和20%WPAC機(jī)械混合后用于反應(yīng)時(shí),EG產(chǎn)率雖催化劑上纖維素催化轉(zhuǎn)化的研究結(jié)果8,我們認(rèn)然較兩種催化劑單獨(dú)使用時(shí)有所提高,但遠(yuǎn)低于為,WP催化劑不僅在纖維素降解轉(zhuǎn)化過(guò)程中具有2%N-20%WPAC催化劑.這表明,Ni和W間存在催化加氫作用,同時(shí)催化劑中W物種的存在對(duì)反應(yīng)顯著的協(xié)同作用.一方面,W物種的存在使纖維素物分子內(nèi)CC鍵的斷裂具有重要的催化作用發(fā)生選擇性CC斷裂而降解為小分子的C2不飽和氣相產(chǎn)物分析結(jié)果顯示,WP催化劑上纖維素化合物;另一方面,WP自身以及Ni等催化加氫活能夠轉(zhuǎn)化生成很少量的CO和CO2,但未檢測(cè)到烴性中心催化不飽和分子加氫反應(yīng)生成EG.因此,可類產(chǎn)物.通過(guò)液體產(chǎn)物中的有機(jī)總碳量計(jì)算纖維素以通過(guò)適宜的加氫組分修飾或借助新的制備方法,轉(zhuǎn)化率為80%-90%,造成反應(yīng)后出現(xiàn)10‰-20%碳調(diào)變催化劑上兩種催化能力的相對(duì)強(qiáng)弱,使WP催損失的原因尚不清楚化劑在纖維素催化轉(zhuǎn)化為EG的反應(yīng)中表現(xiàn)出更好通過(guò)循環(huán)反應(yīng)考察了20%WP/AC催化劑的穩(wěn)的催化性能定性.結(jié)果表明,循環(huán)使用3次后,乙二醇收率由WP催化劑在催化纖維素轉(zhuǎn)化制EG的反應(yīng)中254mol%降至174mol%.圖2為反應(yīng)后催化劑的表現(xiàn)出了良好的性能,在Ni的促進(jìn)下,EG產(chǎn)率可以XRD譜.由圖可知,使用3次后,雖然WP衍射峰增至460mol%.與W2C催化劑相類似,WP催化劑強(qiáng)度略有下降,但其晶相仍保持良好,沒(méi)有檢測(cè)到氧中同樣存在兩種催化中心的協(xié)同作用.Ni作為催化化鎢.另一方面,反應(yīng)后催化劑的CO吸附量由8.3加氫助劑可顯著提高EG產(chǎn)率.該結(jié)果有助于加深umol/g降為6.4μmolg.液體反應(yīng)產(chǎn)物中W元素的理解含W催化劑中W在纖維素轉(zhuǎn)化成乙二醇反應(yīng)中的作用,同時(shí)為發(fā)展新型廉價(jià)的生物質(zhì)轉(zhuǎn)化催化劑提供有益的參考.After 3rd run參考文獻(xiàn)After 2nd runI Lynd L R, Cushman J H, Nichols R J, Wyman C E. Science,1991,251:13After l st run2 Philippidis g P, Smith T K, Wyman C E. Biotechnol Biogs1993.41:8463 Asadullah M, Kaoru F, Keiichi T. Ind Eng Chem, ResFresh 20%WP/AC2001,40:58944 Mohan D, Pittman C U, Steele P H. Energy Fuels, 200620:848中國(guó)煤化工Ed,2006,45CNMHG圖2新鮮鮮和循環(huán)反應(yīng)后的20%WP/AC催化劑XRD譜6 Yan N, Zhao C, Luo C, Dyson PJ, Liu H C, Kou YJ AmFig 2 XRD patterns of fresh and recycled 20%WP/AC catalystsChem soc,2006,128:8714www.chxb.cr趙冠鴻等:磷化鎢催化轉(zhuǎn)化纖維素制乙二醇9317 Luo C, Wang S C, Liu H C Angew Chem, Int Ed, 2007, 46: component mainly promotes catalytic hydrogenation.Tofurther prove this proposition, in this work, we prepared8 JiN Zhang I, Zheng M Y, Wang A Q, Wang H, Wang X D, tungsten phosphide(WP) catalysts supported on AC andChen J G Angew Chem, Int Ed, 2008, 47: 8510silica, and investigated their catalytic behavior in the con9 JiN, Zhang T, Zheng M Y, Wang A Q, Wang H, Wang X Dversion of celluloseShu Y Y, Stottlemyer A L, Chen JG G Catal Today, 2009147:7The preparation of the tungsten phosphide catalysts10 Zhang Y H,Wang A Q, Zhang T. Chem Commun, 2010, 46: comprised three steps [13, 14]: impregnating the support, AC(Norit, 20-40 mesh, ABET 709 m /g) or silica (QingdaoI 1 Zheng MY, Wang A Q, Ji N, Pang J F, Wang X D, ZhangHaiyang Chemical Company, 20-40 mesh, ABET =455 m /g),T. ChemSus chem 2010.3: 63with solutions of ammon2 Ding L N, Wang A Q, Zheng M Y, Zhang T. Chem- (NH4)HPO4, drying the sample at 120"C for 12 h, andSus chem,2010,3:818reduction with a procedure in which the sample was heated3 Shu Y, Oyama S T Carbon, 2005, 43: 1517from room temperature to 350 C at a rate of 5.5 C/min, then14 Clark P, Wang X, Oyama S T J Catal, 2002, 207: 256to 850C at a rate of 1 C/min, and kept at 850C for I h. The5 Li L, Wang X, Shen J, Zhou L, Zhang T. Therm Anal hydrogen gas hourly space velocity(GHSv) was 12 000 hChlorin,2005,82:103After reduction, the phosphide was passivated in 1%O99%N, for 4 h For th英譯文tungsten phosphide catalyst, Ni(NO3)2 was co-impregnatedwith AMT and(NH4h2HPO4, which was followed with theEnglish Textprocedure described above, except that thNowadays, fossil energy depletion and climate temperature was 650C. The nominal loadings of tungstenterioration are driving the development of alternative clean and nickel were 20 wt% and 2 wt%, respectivelyenergy sources. Among various potential solutiX-ray diffraction (XRD) patterns were obtained on aconverting of biomass to energy chemicals and building PW3040/60 XPert PRO(PANalytical) diffractometer. COblock materials is regarded as one of the most attractive chemisorption measurement was conducted on a calvet-typeapproaches because of the carbon neutrality and renewablemicrocalorimeter (Seteram BT2 15)described elsewhereproperties of biomass. Lignocellulose, the most abundant [15]. Before the measurement, the catalyst was treated in Hbiomass on earth, is widely available inflow at 650C for I h. Transmission electron microscopywastes. However, the crystalline and compact structure of ( TEM) analysis was performed on a JEM-2000EX (JEOL)cellulose makes it difficult to degrade. It remains a microscope. The catalytic conversion of cellulose(Merck,llenge to efficiently and selectively convert microcrystalline) was performed in a stainless steel autoclavecellulose into valuable chemicals. Among possible routes (Parr Instrument Company, 100 mI)at a H2 pressure of 61-7], the catalytic conversion of lignocellulose with solid MPa(measured at room temperature)and 245 C for 30 mincatalysts has unique advantages such as good selectivity for For each reaction, cellulose(0. 5 g), catalyst(0.15 g),andtarget products, reusability of catalysts, mild reaction deionized water (50 mI)were charged into the reactor andconditions, and environmental friendliness [5-7]stirred at a rate of 1 000 r/min. The liquid products werePreviously, we have reported that cellulose can be coranalyzed by high performance liquid chromatography. Theverted into polyols with high selectivity over transition metal liquid products were also analyzed by the total orcarbide and phosphide catalysts[8-12]. In particular, over carbon (TOC) method on a Elementar Liqui TOCtungsten carbide(W2 C)supported on activated carbon (AC) instrument. The metal loss from the catalyst after reactionand mesoporous carbon and nickel-promoted tungsten car- was determined by inductively coupled plasma(ICP)usingbide catalysts, the highest ethylene glycol (EG) yield ob- an IRIS Intrepid II XSP instrument(Thermo Electrontained was 75 wt%[10]. To unravel the unique role of tung- Corporation). The gas products were analyzed by gassten carbide in the transformation of cellulose to EG. we chromatography. Cellulose conversions were determined byemployed Ni-W bimetallic catalysts instead of Ni-W2C, and the weight change of cellulose before and after the reactionfound that the Ni-w bimetallic catalysts also exhibited high [5, 8]. The yields of polyols were calculated by the carbonactivity and selectivity[11]. In contrast to w-based catalysts, mole ratio of product and cellulose [12]with nickel phosphide catalysts, the main product was sor中國(guó)煤化工 alyst20%WPbitol rather than EG [12]. These results suggest that the AC showed typiCNMHGnall amount oftungsten component plays an important role in selectively tungsten carbide was arIeu. wien was ascribed to thecracking the C-c bond of the reactant, while the nickel carbothermal reduction of tungsten by the carbon support to932催化學(xué)報(bào)Chin.J.Cua1,2010,31:928932form the carbide during the high temperature preparation of The XRD patterns of the spent catalysts( Fig. 2)showed thattungsten phosphide. In contrast, for the silica-supported the WP phase remained well dispersed after three recyclingcatalyst 20%WP/SiO2, only a very weak peak of the WP runs and no tungsten oxide peaks were seen On the otherphase was observed. The absence of most of the diffraction hand, a comparison of the Co uptake amounts before andpeaks of WP from the 20%WP/SiO2 catalyst suggested a after reaction indicated that the co uptake had slightly de-high dispersion of WP on the silica support. The CO ad- creased (6.4 umol/g) after the reaction. The ICP analysis ofsorption measurement showed a CO uptake of 18.3 umol/g the liquid products showed that 5.2 wt% tungsten from theby 20%WP/SiO2, which was more than twice that by catalyst was leached into the solution after reaction. This20%WP/AC (8.3 umol/g), which further demonstrated that may account for the decrease in catalytic activity. In addition,tungsten phosphide had a higher dispersion on the partial oxidization of the active sites on the catalyst may be20%WP/SiO2 catalyst. The TEM images (not shown) another reason for the deactivationshowed that the particle size of tungsten phosphide onActivity for catalytic hydrogenation is necessary for a20%WP/SiO2 was smaller than on 20%WP/AC. On the catalyst for cellulose conversion to polyols [10, 11]. Thus, we2%Ni-20%WP/AC catalyst, the main phase was still WP, attempted to modify the tungsten phosphide catalyst withwith small amounts of w,c and ni,pnickel to provide more hydrogenating sites on the catalystsThe catalytic conversions of cellulose over the various The Co chemisorption measurement showed that the COcatalysts are listed in Table 1. Over all the tungsten uptake amount over 2%Ni-20%WP/AC was 11.9 umol/phosphide catalysts, cellulose was completely degraded in 30 which was higher than the 8.3 umol/g over the 20%WP/ACinEG was the main polyol product. For 20%WP/AC, the During cellulose conversion, the EG yield was remarkablyEG yield was 25. 4 mol%, with a hexitol yield of as low as 2.3 increased to 46.0 mol% over the nickel-modified tungstenmol%. This result is very close to that over a W2C/AC cataphosphide, which showed notable synergy in thest[8,9]. As mentioned above, a small amount of tungsten 2%Ni-20%WP/AC catalyst On the other hand, over a me-carbide was formed on 20%WP/AC, which may play an chanical mixture of 10%Ni/AC and 20%WP/AC, an EGimportant role in EG formation during cellulose conversion. yield of 34.1 mol% was obtained. Although this value wasTo exclude the influence of tungsten carbide, we used a higher than that over the individual catalysts, it was stillsilica-supported tungsten phosphide catalyst. Again, a good much lower than that from the 2%Ni-20%WP/AC catalystyield of EG was obtained on 20%WP/SiO2, in good agree- This result further demonstrated that a synergistic effectment with 20%WP/AC. The high selectivity for EG in cel- occurred when both Ni and w were present in one catalyst,ulose conversion should be attributed to the catalytic per- probably as neighbors to each other. On one hand, the tungformance of tungsten phosphide. As compared with nickel sten component in the catalysts degraded cellulose into smallphosphide, which we reported recently [12], the product molecules of C2 unsaturated species. On the other hand,selectivities were quite different even though both were tungsten catalyzed the hydrogenation of unsaturated moleetal phosphides. Cellulose was selectively transformed into cules into EG. Thus, with a proper amount of hydrogenatingsorbitol with a high yield of 48.4 mol% over nickel sites or using a novel preparation method to adjust the relaphosphide, while smaller molecule products, such as EG tive amounts of the two kinds of functions on the catalyst,were mainly formed over the tungsten phosphide catalyst By tungsten phosphide catalysts should give a better performcorrelating with our previous work on tungsten carbide and ance for cellulose conversion to EGmetallic tungsten catalysts [8-1l], we conclude that tungstenIn summary, tungsten phosphide catalysts showed goodphosphide functions as the active site for hydrogenation and activity for cellulose conversion to EG. Similar to tungstencarbide catalysts, a synergistic effect of duel catalytic sitesThe gas phase analysis showed that a small amount of co The addition of Ni into tungsten phosphide promoted cataand CO2 were produced but there were no methane or other lytic hydrogenation, and led to a remarkable increase of thealkanes formed during the reaction. The cellulose conversion EG yield to 46.0 mol%, The result is helpful for a betterwas 80%90% of total organic carbon. The reason for the understanding of cellulose conversion into EG over tung-10%-20% carbon loss after reaction is not clear yetsten-based catalysts, and provides less expensive catalystsThe reusability of the tungsten phosphide catalyst was for biomass conversionexamined with recycling tests. After three recycling runs, theH中國(guó)煤化工EG yield over 20%WP/AC decreased from 25.4 mol% to Full-text paper ar17.4mol%,indicatingthatslightdeactivationhadoccurredhttp://www.scCNMH722067