WO2011036189A2

WO2011036189A2 - The catalyst and method of catalytic hydrogenation of hydroxycarboxylic acid esters to glycols

Info

Publication number: WO2011036189A2
Application number: PCT/EP2010/064001
Authority: WO
Inventors: Margarita Petrovna Demeshkina; Alexandr Alexandrovich Khasin; Tatyana Petrovna Minjukova; Valentin Nikolaevich Parmon; Irina Leonidovna Simakova; Mikhail Nikolaevich Simonov; Tamara Mikhailovna Jurieva
Original assignee: Springhill S.A.
Priority date: 2009-09-22
Filing date: 2010-09-22
Publication date: 2011-03-31
Also published as: EA021350B1; EA201200528A1; WO2011036189A3; EP2480329A2; EE200900073A

Abstract

The invention relates to processes for the low-cost production of glycols from esters of hydroxycarboxylic acids. The esters of hydroxycarboxylic acids and hydrogen in gas phase are contacted with the catalyst which contains hydroxysilicate of copper or reduced hydroxysilicate of copper. The reduced hydrosilicate of copper contains metallic copper nanoparticles decorated by amorphous oxyhydroxide of silicon. Such decorated copper nanoparticles have advantageous activity and selectivity in catalytic hydrogenation of hydroxycarboxylic acid esters to glycols.

Description

The catalyst and method of catalytic hydrogenation of hydroxycarboxylic acid esters to glycols

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to processes for the production of diols with high yield and selectivity by hydrogenation of hydroxycarboxylic acid esters in gas phase over copper containing catalysts. In particular, the present invention relates to a process for the production of ethylene and propylene glycols.

Description of Related Art

The ethylene and propylene glycols are used in a wide variety of applications such as monomers in polyester resins; in antifreeze and de-icing fluids; in the manufacture of food, drugs and cosmetic products; and in liquid detergents. At present, commercial production of glycols is petroleum-based and involves hydrolysis of alkylene oxides at high pressure and high temperature.

Since this process starts with ethylene and propylene, the price of the resulting 1,2-diols depends on the price of oil and other hydrocarbon. The new method is required for production glycols from renewable resources such as plants.

It is well known that plants produce carbohydrates from atmospheric carbon dioxide and sunlight in the process of photosynthesis. Furthermore, as carbon dioxide is a greenhouse gas, so any additional removal of the gas from the atmosphere helps to offset the increase in this gas by industrial emissions. The method based on hydroxycarboxylic acids obtained by fermentation of crude biomass is promising way for glycols production (WO 2000030744, US 6455742, US 6479713).

It is known that liquid-phase hydrogenation of carboxyl groups occurs under high hydrogen pressure. To perform the hydrogenation process under milder conditions carboxylic acids are usually converted into more readily reducible esters. Various patents and articles disclose the reduction of hydroxycarboxylic acid esters. For example, the hydrogenation of organic esters to alcohols and glycols in a liquid phase was reported by Adkins and co-workers who were able to achieve 80% yields of propylene glycol from methyl lactate over copper/chromium oxide and Raney nickel catalysts at temperature from 150 to 250 °C and extremely high hydrogen pressures from 20 to 30 MPa (Bowden and Adkins, J. Am. Chem. Soc. 56: 689 (1934); Adkins and Billica, J. Am. Chem. Soc. 70: 3118 (1948); Adkins and Billica, J. Am. Chem Soc. 70: 3121 (1948)). In addition to high pressure high catalyst loading is necessary to achieve these relatively high yields. Broadbent et al. (J. Org. Chem. 24: 1847 (1959)) was able to obtain propylene glycol from ethyl lactate over rhenium black catalysts with yield as high as 80% at 150°C but at very high hydrogen pressure of about 25 MPa.

The hydrogenation of organic esters to glycols in a liquid phase was reported by Luo and coworkers who have achieved 83% yield of propylene glycol from ethyl lactate over Ru-Sn/γ- A1₂0₃ at 150D C and 5.5 MPa. (Luo, G., Yan, S., Qiao, M., Zhuang, J., Fan, K. Appl. Catal. A. 275: 95 (2004)).

The serious disadvantage of all mentioned above hydrogenation processes in liquid phase is necessity to use a high hydrogen pressure.

Carrying out the process of hydrogenation in a vapor phase allows lowering hydrogen pressure. For example, the hydrogenation of organic esters to alcohols and glycols in a vapor phase over the reduced mixture of copper and zinc oxides at 234°C, 1.6 MPa and LHSV=1.06 IT¹ was reported by Bradley and co-workers (Pat. WO8203854, 1982 to Davy McKee Ltd.) who have achieved 97.7% selectivity to propylene glycol and 34.7 % conversion of ethyl lactate. The yield of propylene glycol is 0.038 g of propylene glycol /(ml of catalyst *h). Similar approach was claimed by the patent [GB2150860, 1983 to Davy McKee Ltd.] Reduced mixture of CuO and ZnO oxides was used for hydrogenation of carboxylic acid esters. Carbon dioxide is added to the gaseous mixture in the latter invention.

Copper containing catalysts attracted more efforts to find a process for production of 1,2- propanediol from biomass-derived stuff. R.D. Cortright, M. Sanchez-Castillo, J.A. Dumesic in [Applied Catalysis B: Environmental 39 (2002) 353-359] reported high selectivity and activity of Cu/Si0₂ impregnated catalyst, which comprises copper nitrate over silica surface. Authors achieved 88 % selectivity to 1,2-propanediol at 7 bar and 100 % conversion of lactic acid.

The invention [US Pat. 4628129; to Union Carbide Corporation, 1986] claims Cu/Si0₂ supported catalysts (prepared by impregnation method, as it follows from the text) to be useful for conversion of alkyl oxalates and alkyl glycolates to ethylene glycol.

Despite these efforts, a need for new methods of production of glycols remains that can be performed under relatively mild conditions and which results in high conversion of esters, selectivity to glycols and glycol yield. Summary of the invention

The present invention relates to processes for the low-cost production of glycols from esters of hydroxycarboxylic acids under relatively mild conditions with high conversion of esters, selectivity to glycols and glycol yield. In particular, the present invention provides a catalyst for conversion of hydroxycarboxylic acid esters to 1,2-propanediol, which contains the phase of hydroxysilicate of copper with chrysocolla structure or reduced copper hydroxysilicate. The present invention provides also a process for the production of glycols, which comprises a stage of contacting a mixture of esters of hydroxycarboxylic acid and hydrogen in gas phase with the catalyst, which contains the copper hydroxysilicate or reduced copper hydroxysilicate.

The said copper hydroxysilicate (CuH)₄Si₄0io(OH)8 nH₂0 can be prepared by deposition precipitation method using highly dispersed silica, aqueous soluble copper salt and urea as the raw materials. The said copper hydroxysilicate can also be got from natural deposits of chrysocolla mineral, however in this case mineral admixtures can worsen the catalyst selectivity and/or activity. The said copper hydrosilicate can be prepared also by hydrothermal treatment. The structure of chrysocolla is discriminated from other copper-containing oxides and oxyhydroxides by FTIR method, showing four bands at ca. 470, 670, 1040 and 3620 cm^"1, which are only characteristic of this hydroxysilicate [T.M.Yurieva, G.N.Kustova, T.P. Minyukova, E.K. Poels, A. Bliek, M.P.Demeshkina, L.M.Plyasova, T.A.Kriger, V.I. Zaikovskii. Mater. Res. Innov., 5 (1) (2001) 3-11].

Reduced copper hydroxysilicate can be prepared by treating of copper hydrosilicate with the gas, which contains hydrogen, CO or another reducing agent at elevated temperatures from 100 to 500°C. The reduced copper hydroxysilicate comprises metallic copper nanoparticles decorated with amorphous silicon oxyhydroxide clusters. This system differs a lot from the system "metallic copper particles supported by silica" by its physical, spectral, catalytic and adsorptive properties (including its catalytic activity and selectivity in hydroxycarboxylic acid esters hydro genation). The decoration of metallic copper particles can be unambigously monitored by UV-Vis spectroscopy, since decorated metallic copper particles have much lower energy of surface plasmon resonance (below 16500 cm^"1 , while 17000-18000 cm^"1 is observed for the supported Cu/Si0₂ having no decoration by the support [see e.g. E. Cattaruzza, G. Battaglin, P. Canton, T. Finotto and C. Sada, Mater.Sci. and Eng.: C, 26(5-7) (2006) 1092-1096]. Lowering in energy of surface plasmon resonance energy is caused by changes in the properties of the metallic copper nanoparticle surface due to decoration of the said particles by Si-oxyhydroxide shell, having high dielectric constant. Examples of the impact of Cu nanoparticles decoration by an oxide shell on their optical properties are reported in literature (see e.g. data for Cu-ZnO system [A.A. Khassin, S.F. Ruzankin, V.F. Anufrienko, A.A. Altynnikov, T.V. Larina, J.C. van den Heuvel, T.M. Yurieva and V.N. Parmon. Doklady Phys. Chem. 409 (1) (2006) 193-197.] and for Cu-Cu₂0 [T Ghodselahi, M A Vesaghi and A Shafiekhani, J. Phys. D: Appl. Phys. 42 (2009) 015308]).

The reduction of the hydroxysilicate of copper within the catalyst may be performed after loading the catalyst in the reactor by contacting the catalyst with hydrogen of the hydrogen- containing gas mixture at elevated temperatures, including contacting the catalyst with the mixture of hydrogen and hydro xycarboxylic acid esters.

The catalyst may contain other constituents, which improve its rheological properties, pore structure or mechanical strength, like graphite, zinc oxide etc. Preferably, the content of copper in the catalyst should be more than 10 % wt. It is also preferable that the catalyst doesn't contain other copper-containing oxyhydroxide or oxide compounds, except copper hydroxysilicate, since it may worsen the selectivity of the catalyst. However, minor impurities of such oxides may be present in the catalyst composition and don't affect the catalytic properties significantly.

The catalytic properties of the said catalyst in hydrogenation of hydro xycarboxylic acid esters are significantly advantageous with respect to the known supported Cu/Si0₂ catalysts or with respect the catalysts obtained by the reduction of the copper-containing oxide mixtures (e.g. CuO and ZnO mixture) as it is illustrated by the Examples below.

For the illustration of the method, the esters of aliphatic alcohols and lactic and glycolic acids were used as esters of hydroxycarboxylic acid resulting in formation of propylene and ethylene glycols correspondingly.

Examples

Three catalysts were prepared: two according to the present invention and one according to [R.D. Cortright, M. Sanchez-Castillo, J.A. Dumesic Applied Catalysis B: Environmental 39 (2002) 353-359] as a comparative. The data on these samples are summarized in Table 1.

Example 1

The catalyst was prepared by reductive thermal treatment of a stoichiometric copper hyroxysilicate with Cu:Si ratio of 1 :2 at. with chrysocolla structure under flow of hydrogen and temperature 300°C during 1 hour. The chrysocolla structure of the catalyst before reduction is proved by the presence of bands at 480, 670, 1035 and 3624 cm^"1, catalyst doesn't contain phases of Cu nitrate, CuO, Cu₂0 phases, as it is proved by XRD. After the reduction the catalyst is characterized by the resonant absorption of light at 14600 cm^"1, which shows high extent of decoration of metallic copper particles.

Liquid butyl lactate (a flow rate 0.5 ml/min) evaporated and mixed with a stream of hydrogen (a flow rate 300 ml/min). The gaseous mixture of hydrogen and butyl lactate fed into a tubular quartz reactor packed with 5 g of a catalyst (Table 1, Catalyst number 1). Temperature in the reactor was maintained at about 190±2°C. The pressure - 10 bar. Process was carried out within 24 hours. Mole ration of butyl lactate : hydrogen was 1 : 3.97.

The vaporous mixture exiting the reactor was passed through a water cooled condenser and then through a second refrigerated condenser through which coolant at 0°C was passed. The resulting condensate was analyzed. The condensate has the following composition, %wt : butyl lactate - 28.5; propylene glycol - 33.9; butanol - 34.9; l-hydroxy-2-propanone - 1.9; unidentified by-products - 0.8. The conversion of butyl lactate was 71.5 %mol, selectivity to propylene glycol was 91.3 %mol. The propylene glycol yield (g glycol/g catalyst/hour) was 2.01.

Examples 2-12

Processes of hydrogenation were repeated similarly to an example 1, but under various conditions.

Conditions and results of hydrogenation butyl lactate are shown in Table 2. Examples 13-15 Processes of hydrogenation were performed similarly to an example 1, but methyl lactate was used as ester of hydro xycarboxylic acid.

Conditions and results of hydrogenation of methyl lactate under various conditions are shown in Table 2.

Examples 16-18 Processes of hydrogenation were performed similarly to an example 1, but ethyl lactate was used as ester of hydro xycarboxylic acid.

Conditions and results of hydrogenation ethyl lactate under various conditions are shown in Table 2.

Examples 19-20 Processes of hydro genation were performed similarly to an example 1, but methyl glycolate was used as ester of hydro xycarboxylic acid.

Conditions and results of hydrogenation methyl glycolate to ethylene glycol under various conditions are shown in Table 2.

Examples 21-22 (low copper content)

The catalyst was prepared similarly to Example 1 , but the Cu:Si atomic ratio in the catalyst was 1 :8. The catalyst before reduction contains hydro xysilicate with chrysocolla structure which is proved by the presence of bands at 470, 668, 1040 and 3620 cm^"1, catalyst doesn't contain phases of Cu nitrate, CuO, Cu₂0 phases, as it is proved by XRD, some poorly- crystallized Si0₂ is present in the sample, as follows from XRD and FT-IR data. After the reduction the catalyst is characterized by the resonant absorption of light at 14300 cm^"1, which shows high extent of decoration of metallic copper particles.

Processes of hydrogenation were performed similarly to the examples 7 and 9, but with lower content of copper in the catalyst as described above.

Examples 23-24 (comparative)

The catalyst was prepared by the incipient wetness impregnation of highly dispersed silica (aerosil A- 180) with copper nitrate, as it is proposed by R.D. Cortright, M. Sanchez-Castillo, J. A. Dumesic in [Applied Catalysis B : Environmental 39 (2002) 353-359]. After the reductive treatment the catalyst contains 10 % wt. of metallic copper and Si0₂. The surface plasmon resonance absorption by the reduced catalyst is registered at 17200 cm^"1, which shows the typical supported metallic copper over silica with low extent of copper decoration. Processes of hydrogenation were performed similarly to the examples 7 and 9.

Conditions and results of hydrogenation methyl glycolate to ethylene glycol under various conditions are summarized in Table 2. It can be seen from the data that the proposed by this invention copper hydroxysilicate catalyst is advantageous with respect to the supported Cu/Si0₂ catalyst, having no decoration of the metallic copper.

Table 1. The characteristics of the catalysts

Surface Plasmon

Cu:Si

Phase composition of the resonance band Phase composition of at.

catalyst catalyst maximum for the the reduced catalyst ratio

reduced catalyst

Cu^u decorated by

Copper hydrosilicate

1 1 14600 cm^"1 amorphous

(CuH)₄Si₄0io(OH)₈ nH₂0

hydroxyoxide of silicon

Cu° decorated by

Copper hydrosilicate _l amorphous (CuH)₄Si₄0io(OH)₈ nH₂0 0.14 14300 cm^" hydroxyoxide of and Si0₂ silicon and

amorphous silica

Cu(N0₃)₂ and Si0₂ 0.1 17200 cm^"1 Cu° and Si0₂

Table 1. Conditions and results of hydro genation of esters of hydro xycarboxylic acids.

Claims

1. A catalyst for catalytic hydrogenation of esters of hydroxycarboxylic acids to glycols, wherein the catalyst contains hydroxysilicate of copper.

2. The catalyst according to claim 1, wherein the catalyst contains 10-55 % wt. of copper.

3. The catalyst for catalytic hydrogenation of esters of hydroxycarboxylic acids to glycols, wherein the catalyst contains the reduced hydroxysilicate of copper and its UV-Vis spectrum contains light absorption band having maximum in the range from 11000 to 16000 cm^"1.

4. The catalyst according to claim 3, wherein the catalyst contains 10-55 % wt. of copper.

5. A method for preparation of catalyst according to claim 3, wherein the catalyst is prepared by treatment of the composition, which contains hydroxysilicate of copper, with the hydrogen-containing gas mixture.

6. The method of catalytic hydrogenation of esters of hydroxycarboxylic acids to glycols, which comprises contacting the mixture containing ester of hydroxycarboxylic acid and hydrogen in gas phase with the catalyst wherein the catalyst used is the catalyst according to claims 1-4.

7. The method according to claim 6, wherein the processes is carried out at pressure from 1 to 15 bar and temperature between 140 and 220 °C.

8. The method according to claim 6, wherein the processes is carried out at temperature between 180 and 200 °C.