劉 濤, 王奐祎, 賀站鋒, 王 丹, 蔣 毅

(1. 中國科學(xué)院 成都有機(jī)化學(xué)研究所，四川 成都 610041； 2. 中國科學(xué)院大學(xué)，北京 100049)

近年來，生物柴油在全球的迅猛發(fā)展[1]致使副產(chǎn)物甘油的大量過剩，如何有效利用過剩的甘油成為一個(gè)重要的研究課題。比較有效的解決方式是將甘油通過化學(xué)法，如選擇性氧化、脫水、氫解、鹵化、酯化和醚化、蒸汽重整等途徑[2,3]轉(zhuǎn)化成附加值更高的化工產(chǎn)品。在這些轉(zhuǎn)化途徑中，甘油脫水制備丙烯醛[4]具有較大的發(fā)展?jié)摿Α?/p>

目前，用于甘油脫水制備丙烯醛的固體酸催化劑主要有四大類：氧化物[5～8]、雜多酸[9～11]、分子篩[12～14]和磷酸鹽[15～17]。其中含有WO3的催化劑具有較大的應(yīng)用潛力。Arda Ulgen等報(bào)道WO3/ZrO2[5]或WO3/TiO2[8]催化甘油脫水制備丙烯醛，收率均在70%以上；Lauriol-Garbey P等[7]用SiO2修飾WO3/ZrO2為催化劑，反應(yīng)150 h，轉(zhuǎn)化率達(dá)80%，丙烯醛選擇性>70%；Kraleva E等[18]報(bào)道W-SBA-15催化劑在280 ℃以下反應(yīng)，轉(zhuǎn)化率達(dá)90%，丙烯醛選擇性>70%；Suprun W等[17]使用過渡金屬修飾鋁磷酸鹽為催化劑，其對丙烯醛的選擇性順序?yàn)椋篧>Mo>Cu>V～Fe>Cr>Mn>Ce。以上催化劑，雖然在甘油脫水制備丙烯醛的反應(yīng)中，具有較佳的催化活性，但還難以實(shí)現(xiàn)商業(yè)化應(yīng)用，新催化劑的開發(fā)仍是甘油脫水研究的熱點(diǎn)。工業(yè)Al2O3(含5 wt%TiO2)是一種廣泛使用的載體，而WO3/Al2O3-TiO2催化劑應(yīng)用于甘油脫水高選擇性制備丙烯醛的相關(guān)研究還未見文獻(xiàn)報(bào)道。

Scheme1

1 實(shí)驗(yàn)部分

1．1 儀器與試劑

NOVA 2200e型氮吸附儀；Rigaku D/max-2500/PC型X-射線衍射儀(XRD)；SC-200型和SC3000-B型氣相色譜儀[HP-INNOWAX毛細(xì)管柱(30 m×0.32 mm×0.25 μm)；載氣：高純N2；FID檢測器；1,2-丙二醇為內(nèi)標(biāo)]；STA449C型熱重分析儀(TGA)；自行組裝的TCD-GC裝置(內(nèi)徑9 mm,長度35.0 cm)。

鎢酸銨(H40N10O41W12·xH2O),分析純，國藥集團(tuán)化學(xué)試劑有限公司；30%過氧化氫，分析純，廣東光華化學(xué)廠有限公司；工業(yè)Al2O3(含5 wt%TiO2)，江蘇三劑實(shí)業(yè)有限公司，使用前于750 ℃焙燒2 h，研磨至40 目～60 目后備用。

在反應(yīng)瓶中加入鎢酸銨2.94 g(0.97 mmol)和水10 mL，攪拌使其溶解；加入Al2O3載體10 g，攪拌均勻，于室溫浸漬24 h；于110 ℃干燥10 h制得Cat20[w(WO3)=20%]。

改變鎢酸銨用量，用類似方法制得Catw(表1)。

表 1 制備的實(shí)驗(yàn)條件Table 1 Conditions of preparing

*w(WO3)=m(WO3)/[m(WO3)+m(Al2O3-TiO2)]×100%; T：焙燒溫度

1．3 甘油脫水制備丙烯醛反應(yīng)

2 結(jié)果與討論

2.1 表征

2θ/(°)圖的XRD譜圖

Temperature/℃圖2 Cat20的TGA曲線Figure 2 TGA curvesl of Cat20

2.2 載體與催化劑的織構(gòu)性質(zhì)

表 2 載體和催化劑的織構(gòu)性質(zhì)Table 2 Textural properties of the support and catalysts

w/%圖3 w對脫水反應(yīng)的影響*Figure 3 Effect of w on dehydration of glycerol over

Calcination temperature/℃圖4 焙燒溫度對脫水反應(yīng)的影響Figure 4 Effect of calcination temperature on dehydration of glycerol over

Reaction temperature/℃圖5 反應(yīng)溫度對脫水反應(yīng)的影響Figure 5 Effect of reaction temperature on dehydration of glycerol over

(1)w

(2)焙燒溫度

2.4 反應(yīng)溫度對反應(yīng)的影響

2.5 催化劑的NH3-TPD

Temperature/℃圖的NH3-TPDFigure 6 NH3-TPD prfiles of

w/%圖總酸量與w(a)或焙燒溫度(b)的關(guān)系Figure 7 Effect of w(a) or calcination temperature(b) on the total amount of acid of

[1] Rahmat N, Abdullah A Z, Mohamed A R. Recent progress on innovative and potential technologies for glycerol transformation into fuel additives:A critical review[J].Renew Sust Energ Rev,2010,14(3):987-1000.

[2] Yuguo Zheng, Xiaolong Chen, Yinchu Shen. Commodity chemicals derived from glycerol,an important biorefinery feedstock[J].Chem Rev,2008,108(12):5253-5277.

[3] Zhou Chun-Hui, Beltramini J N, Fan Yong-Xian,etal. Chemoselective catalytic conversion of glycerol as a biorenewable source to valuable commodity chemicals[J].Chem Soc Rev,2008,37(3):527-549.

[4] Kim Y T, Jung K D, Park E D. Gas-phase dehydration of glycerol over ZSM-5 catalysts[J].Micropor Mesopor Mat,2010,131(1-3):28-36.

[5] Ulgen A, Hoelderich W. Conversion of glycerol to acrolein in the presence of WO3/ZrO2catalysts[J].Catal Lett,2009,131(1):122-128.

[6] Lauriol-Garbay P, Millet J M M, Loridant S,etal. New efficient and long-life catalyst for gas-phase glycerol dehydration to acrolein[J].J Catal,2011,280(1):68-76.

[7] Lauriol-Garbey P, Loridant S, Bellière-Baca V,etal. Gas phase dehydration of glycerol to acrolein over WO3/ZrO2catalysts:Improvement of selectivity and stability by doping with SiO2[J].Catal Commun,2011,16(1):170-174.

[8] Ulgen A, Hoelderich W F. Conversion of glycerol to acrolein in the presence of WO3/TiO2catalysts[J].App Catal A-Gen,2011,400(1-2):34-38.

[9] Atia H, Armbruster U, Martin A. Dehydration of glycerol in gas phase using heteropoly acid catalysts as active compounds[J].J Catal,2008,258(1):71-82.

[10] Alhanash A, Kozhevnikova Elena F, Kozhevnikov Ivan V. Gas-phase dehydration of glycerol to acrolein catalysed by caesium heteropoly salt[J].App Catal A-Gen,2010,378(1):11-18.

[11] Atia H, Armbruster U, Martin A. Influence of alkaline metal on performance of supported silicotungstic acid catalysts in glycerol dehydration towards acrolein[J].App Catal A-Gen,2011,393(1-2):331-339.

[12] Schuth F, Jia C J, Liu Y,etal. Small-sized HZSM-5 zeolite as highly active catalyst for gas phase dehydration of glycerol to acrolein[J].J Catal,2010,269(1):71-79.

[13] Kim Y T, Jung K D, Park E D. A comparative study for gas-phase dehydration of glycerol over H-zeolites[J].App Catal A-Gen,2011,393(1-2):275-287.

[14] Lourenco J P, Macedo M I, Fernandes A. Sulfonic-functionalized SBA-15 as an active catalyst for the gas-phase dehydration of glycerol[J].Catal Commun,2012,19(0):105-109.

[15] Qingbo Liu, Zhen Zhang, Ying Du,etal. Rare earth pyrophosphates:Effective catalysts for the production of acrolein from vapor-phase dehydration of glycerol[J].Catal Lett,2009,127(3-4):419-428.

[16] Wang Feng, Dubois J L, Ueda W. Catalytic dehydration of glycerol over vanadium phosphate oxides in the presence of molecular oxygen[J].J Catal,2009,268(2):260-267.

[18] Kraleva E, Palcheva R, Dimitrov L,etal. Solid acid catalysts for dehydration of glycerol to acrolein in gas phase[J].J Mat Sci,2011,46(22):7160-7168.

[19] Song-Hai Chai, Hao-Peng Wang, Yu Liang,etal. Sustainable production of acrolein:Investigation of solid acid-base catalysts for gas-phase dehydration of glycerol[J].Green Chem,2007,9(10):1130-1136.

[20] Benitez V M, Querini C A, Figoli N S,etal. Skeletal isomerization of 1-butene on WOx/γ-Al2O3[J].App Catal A- Gen,1999,178(2):205-218.