JPS6140655B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing methyl tert-butyl ether (hereinafter referred to as MTBE), which is useful as a gasoline additive and a raw material for producing isobutylene. More specifically, isobutylene and methanol are reacted in the presence of an acidic ion exchange resin.
The present invention relates to a method for producing MTBE. It is widely known that MTBE can be produced from isobutylene and methanol using an acidic ion exchange resin as a catalyst, and the source of isobutylene is usually a hydrocarbon fraction with a carbon number of 4 (C ₄ fraction) produced as a by-product from an ethylene manufacturing plant or from this. A so-called spent BB fraction from which 1,3-butadiene has been removed is used. The present inventors used spent BB fraction to obtain MTBE
When we investigated the production method for the reaction, we found that the acidic ion exchange resin used as a catalyst deactivated earlier than expected.As a result of intensive study on countermeasures, we found that after washing the spent BB fraction with water, we started the reaction. It was discovered that the catalyst maintained its activity for a long time when it was supplied, and the present invention was completed. That is, the present invention involves reacting isobutylene and methanol in the presence of an acidic ion exchange resin.
A method for producing MTBE, characterized in that a water-washed mixture of hydrocarbons having 4 carbon atoms containing isobutylene is used as a raw material.
This is a manufacturing method. The acidic ion exchange resin used in the present invention is a strongly acidic cation exchange resin, and typical examples include styrene sulfonic acid resin crosslinked with divinylbenzene and phenolsulfonic acid resin crosslinked with formaldehyde. Preferably, a macroporous type resin is used, and specific examples include Duolite C-26, Duolite C-20, Amberlyte IR-120H, Amberlyte 200, Amberlyst 15, Dowex 50-X-4, and Dowex MSC-1. (registered trademark), etc. A representative example of the C4 hydrocarbon mixture containing isobutylene as used in the present invention is the so-called spent BB fraction remaining after extracting butadiene from the C ₄ fraction by-produced from ethylene production equipment, or a partial fraction from this spent BB fraction. Examples include, but are not limited to, a fraction obtained by removing isobutylene. These spent BB fractions usually contain several ppm of metal cations and amines, but
Catalyst poisoning by metal cations, amines, etc., including 10 ppm of acetonitrile, is well known.In the case of such poisonous substances, the reactor should be divided into two or more, and the first reactor should be poisoned. It is possible to trap the substance and eliminate its influence on the second reactor and beyond, and the deactivated catalyst in the first reactor can be easily restored to activity by acid treatment, but in the case of acetonitrile. In this case, the poisoning spreads throughout the catalyst layer and cannot be dealt with by installing the above-mentioned protective reactor. It was also discovered that the activity of a catalyst deactivated by acetonitrile could not be recovered by ordinary acid or alkali treatment, which was a serious problem industrially. As for the reaction conditions when carrying out the method of the present invention, known reaction conditions described in literature can be employed, except for using a water-washed raw material C ₄ fraction. When carrying out the water washing of the method of the invention, usually C ₄
The mixing ratio of hydrocarbon mixture and water is 1:0.1 to 1:10
Preferably, the ratio is 1:0.5 to 1:2. When MTBE is synthesized from isobutylene and methanol in the presence of an ion exchange resin, the presence of water reduces the activity of the catalyst. Therefore, it is desirable that the methanol used does not contain water. Methanol, which is usually obtained industrially, can be used satisfactorily. A spent BB fraction containing less than a saturation amount of water can also be used, but the water content in the feedstock is preferably 1 wt% or less, more preferably 0.5 wt% or less. Specific reaction conditions for the method of the present invention include pressure of 5 to 50 kg/cm ² , preferably 10 to 30 kg/cm ² and temperature of 10 to 30 kg/cm 2 .
The temperature is 120°C, preferably 30-100°C, and the methanol/isobutylene molar ratio is 0.5-20, preferably 1.0-10. EXAMPLES The present invention will be described in more detail below with reference to Examples, but the present invention is not limited to these Examples. Example 1 400 ml of strong acidic ion exchange resin catalyst Duolite C-26 was placed in a reaction tube made of SUS with an inner diameter of 25 mm and equipped with a jacket.
Filled. 50℃ hot water was poured into the jacket, and 700g/H of Spent BB shown in Table 1 washed with 1:5 SpentBB to water and 182g/H of methanol were supplied to the reaction tube, and the pressure was maintained at 20Kg/ ^cm2 . . Two hours after the start of the reaction, the isobutylene conversion rate was 96.5% and the maximum temperature of the catalyst layer was 102°C, but the reaction was continued for 600 hours and the conversion rate and the maximum temperature of the catalyst layer were observed. It maintained its activity with almost no change even at the maximum layer temperature.

[Table] Comparative Example 1 A reaction was carried out under the same conditions as in Example 1, except that Spent BB having the composition shown in Table 1 was used as it was without being washed with water. Two hours after the start of the reaction, the isobrene conversion rate was 96.5% and the maximum catalyst layer temperature was 102°C, but after continuing the reaction for 600 hours, the isobutylene conversion rate decreased to 90% and the catalyst layer maximum temperature was 97°C. The temperature of the catalyst layer decreased, and the position showing the highest temperature of the catalyst layer also moved to the outlet side of the reactor. This clearly indicates that the activity of the catalyst has decreased.

Claims (1)

[Claims] 1. In a method for producing methyl tert-butyl ether in the presence of an acidic ion exchange resin using a C4 hydrocarbon mixture containing isobutylene and methanol as raw materials, the hydrocarbon mixture is washed with water before being supplied to the reaction. Characteristic method for producing methyl rutatiary butyl ether.