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Process for the preparation of propylene glycol

A technology of propylene glycol and carbon dioxide, applied in the directions of hydrolysis preparation, organic carbonate preparation, etc., can solve problems such as formation of by-products

Inactive Publication Date: 2008-07-23
SHELL INT RES MAATSCHAPPIJ BV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] As described in EP-A-1125915, the presence of ethylene oxide during the hydrolysis of ethylene carbonate has the disadvantage that it leads to the formation of by-products such as ethylene glycol

Method used

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  • Process for the preparation of propylene glycol

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Experimental program
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Embodiment

[0036] A 1 liter autoclave reactor was charged with 0.5 g of MgO catalyst, and propylene carbonate (PC), water, propylene oxide (P0) and 1,2-propanediol (monopropylene glycol, MPG) were added thereto. The amounts (in moles) of these compounds are shown in Table 1. In Example 1, 0.5 g of methyltributylphosphonium iodide (MTBPI) was also added. The reactor was purged with nitrogen or carbon dioxide and the autoclave was subsequently heated to 150°C over the specified number of hours. In some experiments, the reactor was additionally pressurized with carbon dioxide.

[0037] At the end of the experiment, the autoclave was cooled to room temperature and the liquid was stripped for off-line analysis by gas chromatography with sulfolane as standard. The content (in moles) of each compound in the product is shown in Table 1. A known by-product is dipropylene glycol (DPG). Certain amounts of other by-products are also present in the product. Other by-products have not been analyz...

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Abstract

Process for the preparation of propylene glycol from propylene oxide, which process comprises: (a) contacting propylene oxide with carbon dioxide in the presence of catalyst to obtain a first reaction mixture containing propylene carbonate, and (b) contacting at least part of the first reaction mixture with water in the presence of catalyst to obtain a second reaction mixture containing propylene glycol and carbon dioxide, in which process a substantial amount of propylene oxide is present in step (b).

Description

technical field [0001] This invention relates to a process for the preparation of propylene glycol from propylene oxide. Background technique [0002] It is well known that cyclic alkylene carbonates can be obtained by contacting olefin oxides with carbon dioxide in the presence of a suitable catalyst. This method has been described, for example, in EP-A-119840. Furthermore, it is also known that said cyclic alkylene carbonates can be further converted by hydrolysis to yield diols, as described in US-A-5847189. [0003] A process for preparing monoethylene glycol involves reacting ethylene oxide with carbon dioxide in water as described in US-A-6080897 and US-A-6187972. [0004] EP-A-0776890 describes another process for the preparation of ethylene glycol from ethylene oxide, wherein in a second step ethylene oxide is reacted with carbon dioxide, in a third step ethylene carbonate is hydrolyzed, and in Ethylene glycol is recovered in the fourth step. After the carbonatio...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C68/06C07C29/12C07C29/09C07C31/20C07D317/36
CPCC07C29/12C07C31/205
Inventor E·范登海德J-P·朗厄A·米德马
Owner SHELL INT RES MAATSCHAPPIJ BV