Preparation of dimethyl carbonate from methanol and propylene carbonate over Ca-Zr catalyst modified by transition metals
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摘要: 研究了一系列由溶胶凝胶法制备的过渡金属助剂改性的Ca-Zr催化剂对甲醇与碳酸丙烯酯(PC)制备碳酸二甲酯(DMC)的低温反应性能的影响。反应结果表明，催化剂上DMC的选择性的顺序为Co-Ca-Zr>Cu-Ca-Zr> Ca-Zr >Fe-Ca-Zr> Ni-Ca-Zr>Zn-Ca-Zr。其中，用Co改性的催化剂在温度为35 ℃、时间为2 h、甲醇与PC物质的量比为15、催化剂用量为4%的反应条件下，PC转化率可达84.3%，DMC的选择性可达94.5%。采用XRD、FT-IR、XPS、CO2-TPD等手段对催化剂的性质进行了表征。结果表明，增加催化剂的碱性位强度可以提高PC的转化率，而增加催化剂表面的总碱性位含量会降低DMC的选择性。Co改性的Ca-Zr催化剂具有最低的碱性位含量，最高的强碱性位点比例，因此，具有最高的PC转化率和DMC选择性。Abstract: A series of Ca-Zr catalysts modified by different transition metals prepared by sol-gel method were studied for low temperature transesterification of methanol with propylene carbonate (PC) to dimethyl carbonate (DMC). The order of DMC selective of the catalyst was Co-Ca-Zr>Cu-Ca-Zr>Ca-Zr>Fe-Ca-Zr>Ni-Ca-Zr>Zn-Ca-Zr. Among them, the highest PC conversion (84.3%) and DMC selectivity (94.5) was obtained over Co-Ca-Zr catalyst under the reaction conditions of 35 ℃, reaction time of 2 h, methanol to PC molar ratio of 15, and catalyst dosage of 4%. The physicochemical properties of the catalysts were characterized by means of XRD, FT-IR, XPS and CO2-TPD. The results showed that the surface basic content and the percentage of strong basic sites of the catalyst were the main factors affecting the catalytic activity. Increasing the basicity of catalyst might lead to increased PC conversion but decreased selectivity of DMC. The catalyst modified with Co had the lowest surface basic content, the highest percentage of strong basic sites and thus the highest PC conversion and DMC selectivity.
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Key words:
- transition metals modification /
- ca-zr /
- transesterification /
- dimethyl carbonate
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图 3 催化剂的N2吸附-解吸等温曲线(a)和孔经分布(b)
Figure 3 N2 adsorption-desorption isotherms (a) and pore distribution (b) of the catalysts
图 5 Fe-CZ的Fe 2p XPS谱图(a); Ni-CZ的Ni 2p XPS谱图(b); Cu-CZ的Cu 2p XPS谱图(c); Zn-CZ的Zn 2p XPS谱图(d); Co-CZ的Co 2p XPS谱图(e)
Figure 5 Fe 2p XPS spectrum of Fe-CZ (a); Ni 2p XPS spectrum of Ni-CZ (b); Cu 2p XPS spectrum of Cu-CZ (c); Zn 2p XPS spectrum of Zn -CZ (d); Co 2p XPS spectrum of Co -CZ (e)
图 7 催化剂的催化性能
Figure 7 Catalytic performance of the catalysts (60 ℃, 5 h, methanol to PC molar ratio of 15, and catalyst dosage of 4%）
图 8 DMC的选择性与催化剂的碱量(a)以及强碱性位点所占比例(b)的关系
Figure 8 Relationship between DMC selectivity and the amount of basic sites of catalyst (a) and the proportion of strong basic sites (b)
图 9 Co-CZ催化剂上反应条件的优化
Figure 9 Optimization of reaction conditions over Co-CZ catalyst. molar ratio of reactants(a); catalyst content (w% of PC) (b); reaction time(c); reaction temperature (d)
表 1 催化剂的织构参数
Table 1 Texture properties of the catalysts
Catalyst SBET A/(m2·g−1) Pore volume v/(cm3·g−1)a Average pore size d/nmb CZ 7.5 3.0 × 10−2 16.0 Fe-CZ 10.2 5.0 × 10−2 19.8 Co-CZ 3.1 1.3 × 10−2 16.4 Ni-CZ 7.3 1.9 × 10−2 10.7 Cu-CZ 1.1 0.3 × 10−2 11.2 Zn-CZ 3.5 1.5 × 10−2 17.1 a: total pore volume measured at p/p0 = 0.99, b: the pore diameter calculated from the desorption branch of the isotherm using the BJH method 
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表 2 催化剂的结合能值
Table 2 Binding energy values of the catalysts
Catalyst Binding energy/eV Ca 2p Zr 3d O 1s CZ 350.7; 347.0 181.7; 184.0 529.5; 531.6 Fe-CZ 350.2; 346.4 181.0; 183.3 529.2; 531.5 Co-CZ 350.2; 346.5 181.3; 183.6 529.2; 531.3 Ni-CZ 350.9; 346.7 181.3; 183.7 529.5; 531.4 Cu-CZ 350.4; 346.7 181.4; 183.7 529.5; 531.4 Zn-CZ 350.3; 346.6 181.4; 183.7 529.5; 531.4
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表 3 催化剂的总碱位数量和各碱性位点所占比例
Table 3 Base number and the proportion of base sites of the catalysts
Catalyst α peak/% β peak/% γ peak/% Total basicity/
(mmol·g−1)CZ 2.4 56.0 41.6 1.57 Fe-CZ 4.1 43.9 52.0 1.66 Co-CZ 3.5 27.4 69.1 0.66 Ni-CZ 2.3 73.0 24.7 3.24 Cu-CZ 2.9 79.3 17.8 1.25 Zn-CZ 2.9 61.6 35.5 1.08
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表 4 合成DMC的催化剂性能
Table 4 Comparation of the catalytic performance for DMC synthesis
Catalyst Reaction
time t /hReaction
tem. t /℃PC con.
x /%DMC sel.
s /%Ref. CaZr 5 60 85.7 86.5 this work CaFeZr 5 60 84.8 82.7 this work CaCoZr 5 60 84.9 92.2 this work CaNiZr 5 60 84.0 82.1 this work CaCuZr 5 60 84.9 88.9 this work CaZnZr 5 60 84.3 82.0 this work CaO 2 60 ～55.0 - [4] ZrO2 6 140 14.0 50.0 [30] CaCo 2 60 71.6 72.9 [11] CaAl 2 60 53.7 92.8 [13] CaMgAl 2 60 55.3 96.3 [13] MgAl 4 65 10.7 20.9 [31] FeMgAl 4 65 66.2 82.6 [31] CuMgAl 4 65 63.8 81.5 [31]
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[1] TUNDO P, MUSOLINO M, ARICO F. The reactions of dimethyl carbonate and its derivatives[J]. Green Chem,2018,20(1):28−85. doi: 10.1039/C7GC01764B [2] KOHLI K, SHARMA B K, PANCHAL C B. Dimethyl carbonate: review of synthesis routes and catalysts Used[J]. Energies,2022,15(14):5133−5263. doi: 10.3390/en15145133 [3] AN H, ZHANG G, ZHAO X, WANG Y. Preparation of highly stable Ca-Zn-Al oxide catalyst and its catalytic performance for one-pot synthesis of dimethyl carbonate[J]. Catal. Today,2018,316:185−192. doi: 10.1016/j.cattod.2018.03.006 [4] WEI T, WANG M, WEI W, SUN Y, ZHONG B. Synthesis of dimethyl carbonate by transesterification over CaO/carbon composites[J]. Green Chem,2003,5(3):343−346. doi: 10.1039/b210716n [5] TIAN X, ZENG Y, XIAO T, YANG C, WANG Y, ZHANG S. Fabrication and stabilization of nanocrystalline ordered mesoporous MgO–ZrO2 solid solution[J]. Microporous Mesoporous Mater,2011,143(2-3):357−361. doi: 10.1016/j.micromeso.2011.03.015 [6] XU J, CHEN Y, MA D, SHANG J K, SHANG Y X. Li. Simple preparation of MgO/g-C3N4 catalyst and its application for catalytic synthesis of dimethyl carbonate via transesterification[J]. Catal Commun,2017,95:72−76. doi: 10.1016/j.catcom.2017.03.009 [7] KUMAR N, SRIVASTAVA V C. Dimethyl carbonate synthesis via transesterification of propylene carbonate using an efficient reduced graphene oxide-supported ZnO nanocatalyst[J]. Energy Fuels,2020,34(6):7455−7464. doi: 10.1021/acs.energyfuels.0c01091 [8] AHIRE J, BHANAGE B M. Solar light assisted synthesis of CeO2 nanoparticles for transesterification of ethylene carbonate with methanol to dimethyl carbonate[J]. Catal Letters,2022,152(11):3284−3293. doi: 10.1007/s10562-022-03927-2 [9] XUE Y, YU Z, ZHAI S, LI C, WEI X, XU J, WANG F, XUE B. The role of Ce doping on the activity of La2O2CO3 nanosheets catalysts in synthesis of dimethyl carbonate from propylene carbonate and methanol[J]. Catal Commun,2022,171:106526−106530. doi: 10.1016/j.catcom.2022.106526 [10] ZHAO H, SONG H, WANG F, MIAO Z, CHOU L. Low-temperature fabrication of K2O supported mesoporous tetragonal ZrO2 solid base for synthesis of dimethyl carbonate[J]. Mol. Catal,2020,495:111141−111150. doi: 10.1016/j.mcat.2020.111141 [11] HUO L, WANG T, PU Y, LI C, LI L, ZHAI M, QIAO C, BAI Y. Effect of cobalt doping on the stability of CaO‐based catalysts for dimethyl carbonate synthesis via the transesterification of propylene carbonate with methanol[J]. ChemistrySelect,2021,6(38):10226−10237. doi: 10.1002/slct.202102987 [12] WANG H, WANG M, ZHANG W, ZHAO N, WEI W, SUN Y. Synthesis of dimethyl carbonate from propylene carbonate and methanol using CaO–ZrO2 solid solutions as highly stable catalysts[J]. Catal. Today,2006,115(1-4):107−110. doi: 10.1016/j.cattod.2006.02.031 [13] LIAO Y, LI F, DAI X, ZHAO N, SIAO F. Solid base catalysts derived from Ca-M-Al (M = Mg, La, Ce, Y) layered double hydroxides for dimethyl carbonate synthesis by transesterification of methanol with propylene carbonate[J]. Chinese J. Catal,2017,38(11):1860−1869. doi: 10.1016/S1872-2067(17)62898-5 [14] WEI T, WANG M, WEI W, SUN Y, ZHONG B. Effect of base strength and basicity on catalytic behavior of solid bases for synthesis of dimethyl carbonate from propylene carbonate and methanol[J]. Fuel Process. Technol,2003,83(1-3):175−182. doi: 10.1016/S0378-3820(03)00065-1 [15] LUO J, WANG Y, WANG F, LI F, LI L, ZHAO N, XIAO F. Aerobic oxidation of fluorene to fluorenone over copper-doped Co3O4 with a high specific surface area[J]. ACS Sustain. Chem. Eng,2020,8(6):2568−2576. doi: 10.1021/acssuschemeng.9b07480 [16] ZHANG Y F, ZHANG J X, LU Q M, ZHANG Q Y. Synthesis and characterization of Ca3Co4O9 nanoparticles by citrate sol-gel method[J]. Mater. Lett,2006,60(20):2443−2446. doi: 10.1016/j.matlet.2006.01.013 [17] JI X, YANG J, ZHAO N, WANG F, XIAO F. Synthesis of ethylene carbonate by alcoholysis of urea over Zn-Zr mixed oxides[J]. Inorg Chem Commun,2021,134:109061−109067. doi: 10.1016/j.inoche.2021.109061 [18] THOMMES M, KANEKO K, NEIMARK A V, OLIVIER J P, RODRIGUEZ-REINOSO F, ROUQUEROL J, SING K S W. Physisorption of gases, with special reference to the evaluation of surface area and pore size distribution (IUPAC Technical Report)[J]. Pure Appl. Chem.,2015,87(9-10):1051−1069. doi: 10.1515/pac-2014-1117 [19] DUPIN J C, GONBEAU D, VINATIER P, LEVASSEUR A. Systematic XPS studies of metal oxides, hydroxides and peroxides[J]. Phys. Chem. Chem. Phys,2000,2(6):1319−1324. doi: 10.1039/a908800h [20] SOTO HIDALGO K T, ORITIZ-QUILES E O, BETANCOURT L E, LARIOS E, JOSE YACAMAN M, CABRERA C R. Photoelectrochemical solar cells prepared from nanoscale zerovalent iron used for aqueous Cd2 + removal[J]. ACS Sustain. Chem. Eng,2016,4(3):738−745. doi: 10.1021/acssuschemeng.5b00601 [21] LUO J, XUAN K, WANG Y, LI F, WANG F, PU Y, LI L, ZHAO N, XIAO F. Aerobic oxidation of fluorene to fluorenone over Co–Cu bimetal oxides[J]. New J. Chem,2019,43(22):8428−8438. doi: 10.1039/C9NJ00499H [22] WEERAKKODY C, BISWAS S, SONG W, HE J, WASALATHANTHRI N, DISSANAYAKE S, KRIZ D, DUTTA B, SUIB S L. Controllable synthesis of mesoporous cobalt oxide for peroxide free catalytic epoxidation of alkenes under aerobic conditions[J]. Appl. Catal. B,2018,221:681−690. doi: 10.1016/j.apcatb.2017.09.053 [23] XIE R, FAN G, YANG L, LI F. Hierarchical flower-like Co–Cu mixed metal oxide microspheres as highly efficient catalysts for selective oxidation of ethylbenzene[J]. Chem. Eng. J,2016,288:169−178. doi: 10.1016/j.cej.2015.12.004 [24] ZHOU M, XIONG W, LI H, ZHANG D, LV Y. Emulsion-template synthesis of mesoporous nickel oxide nanoflowers composed of crossed nanosheets for effective nitrogen reduction[J]. Dalton Trans,2021,50(17):5835−5844. doi: 10.1039/D1DT00213A [25] PAL N, IM S, CHO E B, KIN H, PARK J. Superparamagnetic NiO-doped mesoporous silica flower-like microspheres with high nickel content[J]. J Ind Eng Chem,2020,81:99−107. doi: 10.1016/j.jiec.2019.08.058 [26] DO NASCIMENTO J R, DOLIVEIRA M R, VEIGA A G, XHAGAS C A, SCHMAL M. Synthesis of reduced graphene oxide as a support for nano copper and palladium/copper catalysts for selective NO reduction by CO[J]. ACS Omega,2020,5(40):25568−25581. doi: 10.1021/acsomega.0c02417 [27] VINAY S P, CHANDRASEKHAR N. Structural and biological investigation of green synthesized silver and zinc oxide nanoparticles[J]. J Inorg Organomet Polym Mater,2020,31(2):552−558. [28] WANG Q, ZHANG Y, ZHENG J, WANG Y, HU T, MENG C. Metal oxide decorated layered silicate magadiite for enhanced properties: insight from ZnO and CuO decoration[J]. Dalton Trans,2017,46(13):4303−4316. doi: 10.1039/C7DT00228A [29] LI H, XIN C, JIAO X, ZHAO N, XIAO F, LI L, WEI W, WUN Y. Direct carbonylation of glycerol with CO2 to glycerol carbonate over Zn/Al/La/X (X=F, Cl, Br) catalysts: The influence of the interlayer anion[J]. J Mol Catal A Chem,2015,402:71−78. doi: 10.1016/j.molcata.2015.03.012 [30] JUAREZ R, CORMA A, GARCIA H. Gold nanoparticles promote the catalytic activity of ceria for the transalkylation of propylene carbonate to dimethyl carbonate[J]. Green Chem,2009,11(7):949−952. doi: 10.1039/b902850a [31] 王琴, 赵海宏, 匡志奇. 过渡金属改性Mg-Al 基固体碱催化剂上碳酸丙烯酯与甲醇合成碳酸二甲酯的研究[J]. 燃料化学学报,2020,48(4):448−455. doi: 10.3969/j.issn.0253-2409.2020.04.008WANG Qing, ZHAO Hai-hong, KUANG Zi-qi. Preparation of Mg-Al based solid base for the transesterification of propylene carbonate and methanol[J]. J. Fuel Chem. Technol,2020,48(4):448−455. doi: 10.3969/j.issn.0253-2409.2020.04.008 [32] BRISTOW P A. Tillett J. G. Transesterification of Cyclic Esters[J]. Tetrahedron Lett,1967,8(10):901−903. doi: 10.1016/S0040-4039(00)90602-6 [33] 魏彤, 王谋华, 魏伟. 氧化钙室温催化碳酸丙烯酯和甲醇的酯交换合成碳酸二甲酯[J]. 催化学报,2003,024(01):52−56. doi: 10.3321/j.issn:0253-9837.2003.01.013WEI Tong, WANG Mou-hua, WEI Wei. Room-temperature catalytic synthesis of dimethyl carbonate from calcium oxide by transesterification of propylene carbonate and methanol[J]. J Catal,2003,024(01):52−56. doi: 10.3321/j.issn:0253-9837.2003.01.013 [34] 冯雪. 碳酸乙烯酯酯交换合成碳酸二甲酯的反应体系研究[D]. 天津: 天津大学, 2016.FENG Xue. Study on the reaction system for the synthesis of dimethyl carbonate by ethylene carbonate ester exchange [D]. Tianjin: Tianjin University, 2016. -
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