JPH07116082B2 - Method for producing 1,4-butylene glycol - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for producing 1,4-butylene glycol. More particularly, it relates to an improved process for producing 1,4-butylene glycol.

(Prior art and problems) 1,4-butylene glycol is used as a raw material for plastics such as polybutylene terephthalate and polyurethane, and also tetrahydrofuran, butyrolactone, 2
-Pyrrolidone, N-alkylpyrrolidone, pyrrolidine,
It is used as an intermediate for the production of adipic acid and the like.

1,4-butylene glycol is produced by the Reppe method using acetylene as a starting material in the old days, and several production methods using butadiene as a starting material have been proposed in recent years. The method via diacetoxybutene-2 has been industrialized. Also,
Recently, a method for producing 1,4-butylene glycol from maleic anhydride, which is inexpensively produced by vapor-phase oxidation of butane in LPG, has been actively studied.

As a method for producing 1,4-butylene glycol using maleic anhydride as a starting material, for example, maleic anhydride is subjected to an alcohol reaction to form a maleic acid ester, and then, for example, in the presence of a catalyst such as copper chromite or copper / zinc. 25 ~ 75
A method of hydrogenating in the gas phase at a pressure of about kg / cm ² and a temperature of about 150 to 240 ° C., or a catalyst such as nickel, copper, copper chromite in an alcohol solvent such as butanol or 2-ethylhexanol. In the presence of 10
There is known a method of hydrogenating in a liquid phase at a pressure of about 0 to 250 kg / cm ² and a temperature of about 200 to 250 ° C.

However, in the above gas phase method, since 1,4-butylene glycol produced is in thermodynamic equilibrium with butyrolactone which is an intermediate product, in order to efficiently obtain 1,4-butylene glycol, hydrogen content should be as low as possible. It is necessary to set the pressure high and the reaction temperature low, but when using these catalysts, the activity is insufficient and it is necessary to adopt high concentration conditions in order to maintain the conversion rate. There is a disadvantage.
Further, in the case of the liquid phase method, a high pressure of about 100 kg / cm ² or more is required, and both have problems in industrialization.

INDUSTRIAL APPLICABILITY In the production of 1,4-butylene glycol using a maleic acid ester as a raw material, the present invention uses a highly active catalyst to efficiently produce 1,4-butylene glycol under relatively mild conditions.
It is intended to produce 4-butylene glycol.

(Means for Solving Problems) The present inventors have previously prepared an acid anhydride such as maleic anhydride or succinic anhydride by adding palladium or copper when producing butyrolactone by hydrogenating in the gas phase. A method using a catalyst containing chromium and chromium has been proposed (JP-A-61-10978).
5) However, according to the subsequent study by the present inventors, although this catalyst has an excellent activity and selectivity for butyrolactone, it can be detected by the acid anhydride as a substrate, its partial hydrogenation product, and a trace amount of by-products. It turned out to be easily poisoned.

Based on this fact, the present inventors further studied, and as a result, this catalyst was converted to 1,4-butylene glycol by hydrogenating a maleic acid ester and its partially hydrogenated succinic acid ester or butyrolactone. It has been found that, when used in the reaction for production, the poisoning of the catalyst is remarkably alleviated, and the activity is hardly reduced.

The present invention has been achieved based on the above findings, and the gist thereof is as a catalyst in a method for producing 1,4-butylene glycol by hydrogenating a maleic acid ester and / or its partially hydrogenated product. Characterized by the use of a modified copper catalyst alloyed with palladium 1,
It exists in the method for producing 4-butylene glycol.

The present invention will be described in detail below.

In the present invention, modified copper alloyed with palladium is used as a catalyst.

The composition of copper and palladium in this catalyst is copper 1
Preference is given to 0.0005 to 10 atoms of palladium per atom, especially 0.001 to 0.1 atoms.

When the content of palladium is relatively low, sintering is likely to occur, so considering the life of the catalyst, the copper component is produced in advance as a chromite salt such as copper chromite or a copper-zinc composite oxide. Prepared by carrying out reduction and alloying by supporting a palladium compound on it,
Catalysts containing palladium, copper and chromium are particularly preferred. At this time, it is desirable that the atomic ratio of copper and chromium is usually selected from the range of 1/10 to 10:10.

The above catalyst is used by supporting it on a usual catalyst carrier such as silica, alumina, titania, zirconia, activated carbon, diatomaceous earth, pumice, zeolite, clay mineral, barium sulfate, barium carbonate, calcium silicate, magnesium silicate and the like.

The catalyst of the present invention may further contain a small amount of co-catalyst components such as barium, manganese, zinc, silicon, alkali, etc. Further, in order to improve the moldability of the catalyst and contribute to the improvement of the catalyst strength. Molding aids such as glass fiber, inorganic whiskers, graphite and carbon fiber may be used in combination. The total of these components is 20 per 100 parts by weight of the catalyst including the carrier.
It is appropriate that the amount is less than or equal to parts by weight.

The preferred catalyst used in the present invention is produced by impregnating and supporting a previously prepared copper chromite with a soluble palladium compound solution, followed by drying, calcination and reduction by a conventional method. If necessary, for example, a preformed carrier, copper sulfate, copper nitrate, soluble copper salts such as copper chloride, chromium nitrate,
Soluble chromium compounds such as chromium chloride, chromium acetate, chromic anhydride, ammonium chromate, ammonium dichromate and soluble palladium compounds such as palladium nitrate, palladium chloride, palladium formate and, if necessary, co-catalyst components simultaneously or sequentially. Impregnated and supported, for example, after fully dried in air at about 150 ° C for about 1 hour,
It is produced by baking at 350 to 400 ° C. for 2 to 4 hours under an air flow and further reduction treatment in an inert gas stream containing hydrogen.

The final composition of the palladium alloyed copper chromite catalyst thus obtained is Cu / Cr in atomic ratio.
= 1 / 10-10, Pd / Cu = 1 / 2000-10 range, especially Cu / Cr =
The range of 1/2 to 2, Pd / Cu = 1/1500 to 1/10 is preferable. This catalyst is presumed to have a structure in which metallic palladium and metallic copper in an alloy state are dispersed in chromium oxide.

The particle size of the catalyst depends on the reaction system, but usually the average diameter is 2
It is preferably about 8 mm, and is molded into various shapes such as a spherical shape, a cylindrical shape, a hollow cylindrical shape, by a known molding method such as tablet molding, extrusion molding, and rolling granulation.

The process of the present invention is a process for producing 1,4-butylene glycol by hydrogenating a maleic acid ester and / or its partially hydrogenated product using the above-mentioned catalyst.

That is, examples of the raw material used in the present invention include maleic acid diester, succinic acid diester which is a partial hydrogenated product of maleic acid diester, and butyrolactone. Further, it may be a mixture of maleic acid diester, succinic acid diester and butyrolactone.

In some cases, in addition to these, a fumaric acid diester which gives a product similar to a maleic acid diester by hydrogenation, a maleic acid monoester or a mixture of maleic acid and an alcohol may be contained. .

In addition, it is preferable to select a lower alcohol having a carbon number of 5 or less from the viewpoint of reactivity and boiling point as the alcohol component constituting these raw material esters, and to separate the target product from unreacted products and partial hydrogenation. It is decided in consideration.

Hydrogen used in the hydrogenation reaction is usually used in a molar ratio of 100 to 2000 times with respect to the maleic acid ester and / or its partially hydrogenated product which is a raw material. The reaction gas may contain components inert to the reaction such as nitrogen, argon, carbon dioxide, methane and ethane in addition to hydrogen,
Although it can be recycled, the amount of impurities in hydrogen is preferably 50% by weight or less, more preferably 15% by weight or less.

The hydrogenation of the present invention can be carried out in a gas phase reaction under a relatively low pressure or in a liquid phase reaction under a relatively high pressure of 100 kg / cm ² or more, but at a relatively low pressure of 10
Gas phase reactions under pressures below 0 kg / cm ² are especially preferred as hydrogen compressor power is reduced.

When carrying out a gas phase reaction under a relatively low pressure, the pressure is 1
The range of -100 to 100 kg / cm ² , especially 10 to 80 kg / cm ² , is desirable, and the reaction temperature is preferably 150 to 350 ° C, particularly 160 to 240 ° C.

Regarding the reaction pressure, even within the above range, the higher the pressure, the higher the selectivity of 1,4-butylene glycol, which is the target, and the lower the reaction temperature, the lower the target, the target.
It is recognized that the selectivity of 1,4-butylene glycol is high.

When carrying out the liquid phase reaction under relatively high pressure, the pressure is preferably in the range of 60 to 250 kg / cm ² , particularly 100 to 150 kg / cm ² , and the reaction temperature is 160 to 280 ° C., especially 200-250
Performed at ° C.

(Effects of the Invention) The method of the present invention uses a specific high activity catalyst to obtain 1,4,4 from maleic acid ester and / or its partial hydrogenated product under relatively mild conditions with high conversion and selectivity. Butylene glycol can be obtained, and the activity of the catalyst is not easily deteriorated due to poisoning, which is extremely advantageous in industrial production of 1,4 butylene glycol.

(Examples) Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples as long as the gist thereof is not exceeded.

Catalyst Production Example 1 Commercially available copper chromite catalyst (N-202D, CuO37 manufactured by JGC Chemical Co., Ltd.)
_{~39wt%, Cr 2 O 3 36~38wt} %, MnO 2 1.5~2.2wt%, BaO0.
_{7~1.0wt%, Na 2 O1.8wt%,} SiO 2 10.0wt%, the graphite 3.5~4.0wt%), aqueous palladium nitrate solution was impregnated with solution prepared by diluting with acetone, dried in air at room temperature, a stream of nitrogen At 300 ° C. for 3 hours to prepare catalyst 1 containing 0.3 wt% of Pd. Pd in the catalyst produced in this way
The / Cu atomic ratio was 6/1000. The catalyst was alloyed by hydrogen reduction in the reactor.

Example 2 of production of catalyst Commercially available copper chromite catalyst (N-203SD, CuO45 manufactured by JGC Corporation)
wt%, Cr ₂ O ₃ 44 wt%, and MnO ₂ and BaO in small amounts), quartz powder, zinc oxide and water in a weight ratio of 80: 20: 0.1:
Knead at a ratio of 200, further add an aqueous solution of palladium nitrate to dry, and after molding into a pellet of 5 mmφ × 5 mmL using a tablet molding machine, dry at 350 ° C for 3 hours, copper chromite 79.7 wt%, Quartz powder 19.9wt%, zinc oxide 0.1wt% and Pd
A catalyst 2 containing 0.28 wt% was obtained. The Pd / Cu atomic ratio in this catalyst was 6/1000. The catalyst was alloyed by hydrogen reduction in the reactor.

Example 1 A reactor having an inner diameter of 25.4 mm was obtained in the above-mentioned catalyst production example.
2 g of catalyst 1 and catalyst 2 were filled respectively, and glass beads (3 mmφ) were filled on top of them to form an evaporation layer. Then, nitrogen gas containing 4% hydrogen at 150 ° C. was passed at 20 Nl / hr for 4 hours for preliminary reduction, then the hydrogen concentration was set to 100%, the temperature was raised to 270 ° C., and reduction treatment was performed for 1 hour.

Diethyl maleate (hereinafter abbreviated as DEM) was sent by a pump to the evaporation layer in the upper part of the reactor, carried along with the hydrogen stream and passed through the catalyst layer to carry out the hydrogenation reaction. Reaction conditions are temperature
195 ℃, 0.19g-DEM / g catalyst / hr, H ₂ / DEM (molar ratio = 33
0), and the total pressure was 9 kg / cm ² G. The reaction product was condensed by ice-cooling and collected, and the collected liquid was analyzed by gas chromatography. The reaction results are shown in Table 1. For comparison, a case where a commercially available copper chromite catalyst (N-202D manufactured by JGC Chemical Co., Ltd.) was used as a comparison catalyst is also shown.

Example 2 In Example 1, only the catalyst 1 was used, the supply ratio of the raw material gas and the hydrogen gas was LHSV 0.34, the temperature was 177 ° C.,
In addition, Table 2 shows the results of hydrogenation reaction of diethyl maleate in the same manner as in Example 1 except that the total pressure was 40 kg / cm ² G.

Claims (2)

[Claims] 1. A method for producing 1,4-butylene glycol by hydrogenating a maleic acid ester and / or its partially hydrogenated product, using a modified copper catalyst alloyed with palladium as a catalyst. A method for producing 1,4-butylene glycol, which comprises: 2. The method for producing 1,4-butylene glycol according to claim 1, wherein copper chromite alloyed with palladium is used as a catalyst.