Key Laboratory for Green Chemical Key Laboratory for Green Chemical Technology of the Ministry of Education Technology of the Ministry of Education

Key Laboratory for Green Chemical Key Laboratory for Green Chemical Technology of the Ministry of Education Technology of the Ministry of Education

文献报告文献报告2012.12.302012.12.30

胡宗元

Background

各种合成方法的比较

1 、环氧乙烷 (EO) 水合法： EG 的选择性和产率低，以石油为原料生产的 , 目前石油价格上涨 , 面临产量不足的问题 , 经济性会降低。

2 、由合成气合成乙二醇：天然气、石油残渣和煤是合成气的原料，资源丰富 , 价格便宜。由合成气经草酸酷合成乙二醇反应条件温和 , 不需高压 , 如果能进一步改进催化剂 , 提高选择性 , 进行工业放大 , 是近年来被公认为技术性和经济性较好的一种工艺路线。

草酸酯催化加氢的研究制乙二醇的原理

This indirect synthesis process includes two steps: the coupling of CO with nitrite esters to oxalates, and the hydrogenation of oxalates to EG

1: CO 偶联反应： 2CO+2RONO→2NO+(COOR)2

再生反应： 2ROH+1/2O2+2NO→2RONO+H2O

总反应为 ： 2CO+2ROH+1/2O2→(COOR)2+H2O

R=CH3 or C2H5

2 ： (COOR)2+2H2 →ROOCCH2OH+ROH

ROOCCH2OH+2H2 →HOCH2CH2OH+ROH

总反应为： (COOR)2+4H2 →HOCH2CH2OH+2ROH

R=CH3 or C2H5

EG 还可与 H2 继续发生反应，分解成乙醇和水： HOCH2CH2OH+H2 →CH3CH2OH+H2O

草酸酯一个酯基发生加氢反应生成乙醇酸酯，之后另一个酯基继续加氢生成 EG

草酸酯加氢催化剂的研究进展草酸酯催化加氢生产 EG 的工艺可分为以 Ru 等贵

金属催化剂为主的液相均相加氢法和以 Cu 催化剂为主的非均相气相加氢法。

1 ：液相均相加氢催化剂的研究：Matteoli et al. have investigated the homogeneous hydrogenation of oxalates, and obtained an EG yield of 82% under H2 pressure of 20 MPa at 453K using Ru(CO)2(Ac)2(PBu)3 as the catalyst. Recently, Teunissen and coworkers applied Ru-based homogeneous catalysts in the hydrogenation of dimethyl oxalate (DMO); an EG yield of 95% was obtained under milder conditions (7 MPa, 373 K).

Cu-based catalysts supported on different carriers (SiO2,Al2O3,

ZnO, and La2O3)were studied, among which the Cu/SiO2 catalyst

afforded the highest yield of EG in the hydrogenation of DMO and DEO due to the weak acidic and basic properties of SiO2.

Recently, mesoporous materials such as hexagonal mesoporous silica (HMS) and SBA have been used as supports for the reaction.

2: 非均相气相加氢催化剂的研究

homogeneous catalysts are expensive and suffer from separation issue

Cu-based heterogeneous catalysts

ammonia evaporation (AE), ion exchange, sol–gel, deposition precipitation, and impregnation have been used to fabricate silica-supported copper catalysts.

草酸酯催化加氢制乙二醇

1:Catalyst preparation

焙烧后的 Cu/SiO2 催化剂

还原后的 Cu/SiO2 催化剂

AE 法制的催化剂透射电镜（ TEM ）图

the AE method could effectivelythe AE method could effectivelydisperse copper species on the supportsdisperse copper species on the supports

2 ： mesoporous materials as support

It is well known that mesoporous materials which possess high surface area, large pore volume, regular structure, uniform pore size distribution, and relative high thermal stability.

mesoporous materials such as HMS ， SBA-15 ， FSM-16 ， M41S

TEM image of 50% Cu/SBA-15TEM image of 5-Cu-com-SiO2

TEM images for 5-Cu-HMS

Compared with the silica-supported one, the copper-containing HMS sample exhibits much better DMO conversion and EG selectivity under the same reaction conditions, which

may be attributed to the higher copper surface area and stronger copper–silica interaction.

3:the effect of promoter such as boric oxide

Stable and efficient B–Cu–SiO2 catalysts for the

hydrogenation of dimethyl oxalate (DMO) to ethylene glycol were prepared through urea-assisted gelation followed by impregnation with boric acid.

1. a 1. b

a suitable amount of boric oxide doping tended to improve copper dispersion and retard the growth of copper particles

TEM images of catalysts reduced by 5% H2-95% Ar

at 623 K: (a) Cu-SiO2; (b) 1B-Cu-SiO2

Catalytic stability was greatly enhanced in the B–Cu–SiO2 catalyst, because of the formation and preservation of appropriate distributions of Cu+ and Cu0 species on the catalyst surfaces. The effect of boric oxide was attributed to its relatively high affinity for electrons, which tended to lower the reducibility of the Cu+ species.

???

草酸酯催化加氢制乙醇酸酯

草酸酯制催化加氢第一步是生成乙醇酸酯，草酸二甲酯（ DMO ）生成乙醇酸甲酯（ MG ） , 草酸二乙酯生成乙醇酸乙酯（ MPEG ）。乙醇酸酯是一种非常重要的有机化工中间体 , 广泛用于化工、医药、农药、饲、香料和染料等诸多领域。

草酸二甲酯 (DMO) 选择性加氢得到 MG ，经济性及其绿色化都要远远优于其它制备方法。

Synthesis of MG by hydrogenation of Dimethyl Oxalate over Cu-Ag/SiO2 Catalyst

reaction temperature at 473.2K, 40-60 mesh catalyst diameter, H2/DMO ratio 40, and 1.0 h-1of LHSV

the conversion of DMO is 90.6% ， and the selectivity of MG can reached 89%

Ag/SiO2 catalyst for the regioselective synthesis of

methyl glycolate and ethylene glycol

A:Conversion of DMO and MG selectivity vs. time on streamB: Conversion of DMO and EG selectivity vs. time on stream

Reaction conditions: catalyst (2 g), 493 K for A and 553 K for B, 2.5 MPa, LHSV =0.2h-1,and H2/DMO=100 (mol

mol-1).

Ag/MCM-41 catalyst for the chemoselective synthesis of methyl glycolate and ethylene glycol

The highest selectivity to MG and EG could be up to 95% and 99% at 493K and 553K respectively.

草酸酯催化加氢制乙醇

由前面可知，草酸酯催化加氢生成乙二醇，在 H2

环境及催化剂作用下， EG 还可以与 H2 反应分解成乙醇和水。 乙醇是重要的大宗化工产品 广泛用于医药、食品、燃料、化工等行业，也是石油的潜在替代燃料。 目前一些乙醇制备工艺为乙酸加氢制乙醇工艺、淀粉发酵制乙醇工艺、纤维素乙醇工艺等，也可以通过合成气催化制乙醇。

Synthesis of Ethanol via Syngas on Cu/SiO2 catalysts

A:DMO conversion and product selectivities as functions of reaction temperature (453− 573 K).B:DMO conversion and EtOH selectivity vs time on stream at 553 K.

关注的一些问题

1 ： DMO 或 DEO 催化加氢中活性中心是 Cu0 ， Cu+, 还是Cu0 和 Cu+ 的协同作用，关于反应机理的探讨

2 ：催化剂的选择性合成反应，如改变温度、压力等工艺条件控制反应的选择性

3 ：介孔分子筛如 HMS,SBA-15 ， MCM-41 的应用

References

Effect of boric oxide doping on the stability and activity of a Cu-SiO2 catalyst for hydrogenation of DMO to EG

Synthesis of Ethanol via Syngas on CuSiO2 with balanced Cu-Cu+ sites

High activity and selectivity of AgSiO2 catalyst for hydrogenation of DMO

Ethylene glycol properties, synthesis, and applications

Highly active and selective copper-containing HMS catalyst in the hydrogenation of DMO to EG

One Pot Synthesis of Ultra-High Copper Contented CuSBA-15 material

Synthesis of Methyl Glycolate by Hydrogenation of Dimethyl Oxalate over Cu-AgSiO2 Catalyst

AgMCM-41 as a highly efficient mesostructured catalyst for the chemoselective synthesis of methyl glycolate and ethylene glycol