JPH04352771A - Production of propylene oxide - Google Patents

Abstract

PURPOSE:To obtain the subject compound useful as a raw material for polypropylene glycol, etc., in high productivity at a low cost without producing by-product by reacting propylene with hydrogen and oxygen in the presence of a specific catalyst. CONSTITUTION:Propylene oxide is produced by reacting propylene with oxygen and hydrogen in the presence of a catalyst consisting of a group VIII metal of the periodic table and crystalline titanosilicate at 0-150 deg.C optionally in a solvent (e.g. butyl alcohol). The catalyst can be produced by supporting 0.1-10wt.% of a metal such as palladium on a titanosilicate by impregnation, etc. The molar ratio of Ti in the titanosilicate used as the catalyst to propylene is selected to be 0.00001-0.1. The reaction proceeds without using expensive hydrogen peroxide.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing propylene oxide, which is industrially important as a raw material for polypropylene glycol and the like.

0002

BACKGROUND OF THE INVENTION Known methods for producing propylene oxide include the chlorohydrin method, which produces calcium chloride as a by-product, the Halcon method, which co-produces t-butyl alcohol and styrene monomer, and the peracetic acid method, which co-produces acetic acid.

Also known is a method using hydrogen peroxide as an auxiliary raw material and crystalline titanosilicate as a catalyst (eg, US Pat. No. 4,833,260).

0004

[Problems to be Solved by the Invention] However, the chlorohydrin method has problems such as the fact that the chlorine used is not effectively used for dehydrochlorination with milk of lime, and the treatment of large amounts of calcium chloride produced as a by-product. . The Halcon method and the peracetic acid method require securing a market for a large amount of co-products, and the method using hydrogen peroxide requires more than the same mole of expensive hydrogen peroxide, so there is a problem in its economic efficiency.

[0005] For these reasons, it has been desired to develop a highly selective epoxy compound production process that does not produce co-products and does not use expensive hydrogen peroxide as a raw material.

[0006]

[Means to solve the problem] In view of the current situation,
As a result of extensive studies, the present inventors found that when propylene is reacted with hydrogen and oxygen using a catalyst consisting of a Group VIII metal in the periodic table and crystalline titanosilicate,
It was discovered that propylene oxide can be obtained with high selectivity, and the present invention was completed.

[0007] That is, the present invention is directed to
The present invention provides a method for producing propylene oxide, which is characterized in that propylene is reacted with hydrogen and oxygen using a catalyst made of a group II metal and crystalline titanosilicate.

The method of the present invention will be explained in detail below.

[0009] In the process of the present invention, a catalyst comprising a metal from group VIII of the periodic table and a crystalline titanosilicate is used. The titanosilicate mentioned here is “
Silicalite” (crystalline SiO with a zeolite structure)
2, E. M. As disclosed by Flanigen et al. (Nature, 271, 512 (1978)), which is obtained by replacing a part of the silicon forming the crystal lattice with titanium. Titanosilicate may be synthesized by any method, and examples of synthesis include JP-A-56-96720. The amount of titanium contained in the titanosilicate can be defined as the silica/titania ratio (molar ratio), and the silica/titania ratio may be from 5 to 200. If the amount of titanium is too small, the activity as a catalyst will not be sufficient, and if it is too large, the crystal structure of the titanosilicate will be destroyed, which is not preferable. In addition, the components contained in titanosilicate are not limited to titanium, but include boron, aluminum, phosphorus, vanadium, chromium, manganese, iron,
It may contain one or more elements such as gallium and zirconium.

The prepared titanosilicate may be used as it is or after being molded. When molded and used, a binder is generally used, but the type of binder is not particularly limited, and for example, silica, alumina, etc. are used.

In the method of the present invention, a catalyst consisting of a group VIII metal in the periodic table and crystalline titanosilicate is used; however, any group VIII metal may be used as the group VIII metal. . Typically, palladium, platinum, iridium, rhodium, ruthenium, etc. can be used, with palladium being particularly preferred. Also, Chapter V
The Group III metal may be supported on crystalline titanosilicate, or may be supported on silica, alumina, activated carbon, etc. and then physically mixed with titanosilicate. When supporting Group VIII metals, there are no particular restrictions on the supporting materials, but typical examples include, for example, in the case of palladium,
Palladium (II) chloride, tetraamminepalladium (II) chloride, palladium (II) acetate, etc. can be used. Although there are no particular limitations on the method of supporting these metals on titanosilicate, an impregnation method or the like may be used.

[0012] The content of Group VIII metal in the periodic table in titanosilicate is 0.5% as a metal atom.
1 to 10 wt% is preferable. If it is less than 0.1 wt%, the effect is small, and if it exceeds 10 wt%, it is disadvantageous from an economic standpoint. When a group VIII metal in the periodic table is supported on titanosilicate by a method such as impregnation, it can be used as a catalyst after being calcined and/or reduced as necessary. The firing can be carried out under the flow of an inert gas or an oxygen-containing gas. There are no particular restrictions on the firing temperature and time, but for example, 30 minutes to 24 minutes at 100 to 700°C.
All you have to do is bake it for a while. In addition, when performing reduction, there are no particular restrictions on the reducing agent, reduction temperature and time as long as the noble metal component is reduced, but for example, using hydrogen etc. as the reducing agent,
Reduction may be carried out at room temperature to 500°C for 30 minutes to 24 hours.

The prepared catalyst may be used as it is, or may be used in the reaction with the addition of a diluent such as silica or alumina. Before using in further reactions, prepared Part VII
The Group I metal-supported zeolite catalyst can also be used after being reduced in a stream of hydrogen-containing gas.

[0014] Furthermore, when carrying out the reaction, a solvent may be used if necessary. As the solvent, polar solvents such as water, alcohols having 6 or less carbon atoms, ketones, glycols, and carboxylic acids are preferable.

The reaction method may be continuous flow type, semi-batch type or batch type, but continuous flow type is preferable from the viewpoint of productivity.

[0016] The reaction temperature is preferably 0 to 150°C, and 10 to 1
00°C is preferred. Further, when using a solvent, if the reaction temperature exceeds the boiling point of the solvent, the reaction can be carried out under pressure. There is no particular restriction on the reaction pressure, but normal pressure to 20
A range of 0 atm is good.

In the method of the present invention, oxygen is used as one component of the reaction raw material, but it is also possible to use an oxygen-containing gas such as air.

[0018] There is no particular restriction on the content of each raw material in the supplied gas, but propylene (C3H6): 10 to 50 vol.
1%, hydrogen (H2): 5-40vol%, oxygen (O2)
: 5 to 50 vol% is good. Further, from the viewpoint of safety, the content of each raw material is preferably outside the explosive range, and may be diluted with an inert gas such as nitrogen.

The amount of catalyst used in the reaction is the titanium in the titanosilicate and 1 of the raw material supplied per unit time.
Although it can be defined by the molar ratio of propylene, it is sufficient to use a catalyst in an amount such that the titanium/propylene ratio is 0.00001 to 0.1.

The time required for the reaction can be defined as the gas hourly space velocity (total volume of C3H6, H2, O2 and inert gas supplied per hour/unit catalyst volume; hereinafter abbreviated as GHSV). , GHSV is 2000
~40000hr-1 (20°C) is good.

[0021]

Effects of the Invention According to the present invention, propylene and By reaction with hydrogen and oxygen,
Propylene oxide can be obtained with high selectivity, which is significant from an industrial standpoint.

[0022]

[Examples] The present invention will be explained in more detail using Examples below, but these Examples merely show the outline of the present invention, and the present invention is not limited to these Examples. . Example 1 A titanosilicate with a silica/titania ratio of 67 (determined by ICP emission spectrometry) prepared according to the method of JP-A-56-96720 was treated with an aqueous solution of tetraamminepalladium(II) chloride. Add so that the weight of palladium atoms is 0.5 wt%,
Stir and mix for an hour. After evaporation to dryness, 5% at 150℃ for 1 hour
It was reduced under diluted hydrogen flow and used as a catalyst.

The reaction was carried out using a normal pressure, liquid phase, flow system reactor.

[0024] 1.0 g of catalyst was mixed with 60 g of t-butyl alcohol.
ml, and C3H6, H2, and O2 were supplied thereto at 60, 40, and 40 mmol/hr, respectively, and this was diluted with nitrogen to give GHSV=7970 hr-1 (at 20°C
). The reaction temperature was 45°C.

The reaction product was analyzed by gas chromatography. The results up to 5 hours after the start of the reaction are shown in FIG. Furthermore, the selectivity of each product at 5 hours from the start of the reaction was 98.6% for propylene oxide and 98.6% for propane (C3H8).
It was 1.4%.

Examples 2 and 3 The supply amounts of C3H6, H2, and O2 were set to 60, 80,
The reaction was carried out in exactly the same manner as in Example 1, except that the reaction rates were 40, 60, 40, and 80 mmol/hr. Reaction start 5
The results after hours are shown in Table 1.

[0027]

[Table 1] Examples 4 and 5 Except for using catalysts in which the weight of palladium (Pd) atoms relative to titanosilicate was 2.5 wt%, respectively.
The reaction was carried out in exactly the same manner as in Example 1. Table 2 shows the results 5 hours after the start of the reaction.

[0028]

[Table 2] Examples 6 to 9 The examples were carried out except that a titanosilicate with a silica/titania ratio of 33 was used as the titanosilicate supporting palladium, and the reaction temperature was 25, 45, 65, and 82°C, respectively. The reaction was carried out in exactly the same manner as in Example 1. Reaction start 5
The results after hours are shown in Table 3.

[0029]

[Table 3] Example 10 The reaction was carried out in the same manner as in Example 1, except that a titanosilicate with a silica/titania ratio of 33 was used as the titanosilicate supporting palladium, and water was used as the reaction solvent. Ta. 5 hours after the start of the reaction, propylene oxide was 1
．． 56 mmol was obtained. Further, the selectivity of each product 5 hours after the start of the reaction was 99.8% for propylene oxide and 0.2% for propane.

Examples 11 and 12 Using titanosilicate with a silica/titania ratio of 15,
The reaction was carried out in exactly the same manner as in Example 1, except that catalysts in which palladium and platinum were used as supported metals (supporting rate 0.5 wt%) were used, respectively. Table 4 shows the results 5 hours after the start of the reaction.

[0031]

[Table 4] Example 13 A catalyst was prepared by pulverizing and mixing 1 g of 0.5 wt% palladium-supported activated carbon (manufactured by Nippon Engelhard Co., Ltd.) that had been hydrogen-reduced at 150°C for 1 hour and 1 g of titanosilicate with a silica/titania ratio of 33. The reaction was carried out in exactly the same manner as in Example 1, except that the following was used. Five hours after the start of the reaction, 1.36 mmol of propylene oxide was obtained. Further, the selectivity of each product 5 hours after the start of the reaction was 99.8% for propylene oxide and 0.2% for propane.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the relationship between the elapsed time and the amount of propylene oxide produced in the epoxidation of propylene in Example 1.

Claims (1)

[Claims] 1. A method for producing propylene oxide, which comprises reacting propylene with hydrogen and oxygen using a catalyst comprising a Group VIII metal in the periodic table and crystalline titanosilicate.