JP2866720B2 - Method for producing tertiary butylamine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing tertiary butylamine, and more particularly, to a method for producing tertiary butylamine from isobutene and ammonia in a single-stage reaction operation. .

Tertiary butylamine (hereinafter abbreviated as t-butylamine) is a useful compound used as a raw material or a solvent for synthesis of rubber chemicals, agricultural chemicals, pharmaceuticals, and the like. Used as an accelerator.

[Conventional technology]

t-Butylamine is currently produced by adding hydrocyanic acid to isobutene, then converting it to acid amide, and removing sodium formate under alkaline conditions (USP 4,131,642);
A method of reacting butyl alcohol with hydrocyanic acid and then reacting methanol and water in the presence of an acid catalyst to give the desired product as methyl formate (EP 50,870);
A method in which butyl ether (MTBE) is reacted with hydrocyanic acid and then refluxed in a mixed solvent of water and methanol (EP 50,
869).

As described above, the conventional method for producing t-butylamine is complicated and involves many steps, as described above, and uses toxic and complicated handling materials such as hydrocyanic acid, and produces by-products such as methyl formate and sodium formate. And so on.

As a method for producing t-butylamine, which does not have the above-described problems and does not produce by-products in one step, a method of directly reacting isobutene and ammonia with silica-alumina or a zeolite as a catalyst has been proposed. (JP-A-57-4948, JP-A-63-159354, JP-A-64-7545)
3, J. Org. Chem., 53 4594-4596 (1988)]. However, in the method using silica-alumina or zeolites as a catalyst, the reaction rate is low, the space-time yield (STY) is low, and the catalyst performance has not reached a level that can withstand industrial operation. There is.

[Problems to be solved by the invention]

In a conventional method for producing t-butylamine,
As described above, there are problems in that the process is long, a highly toxic starting material is used, and by-products are produced together. Proposals for a method for obtaining t-butylamine from isobutene and ammonia in one step have disadvantages such as poor activity of the catalyst used, low reaction rate, low space-time yield, and inability to withstand industrial operations.

An object of the present invention is to provide a method for producing t-butylamine which does not have the above-mentioned problems.

[Means for solving the problem]

In order to solve these problems, extensive studies were conducted on a method for producing t-butylamine, in particular, on a catalyst used for reacting isobutene with ammonia. As a result, it was found that by performing the reaction in the presence of a mixed oxide of titania and silica as a catalyst, t-butylamine can be obtained at a high reaction rate and high selectivity from isobutene and ammonia directly in a single-stage reaction. The invention has been completed.

That is, the present invention is a method for producing t-butylamine, which comprises reacting isobutene with ammonia in the presence of the above-mentioned catalyst.

The mixed oxide used as a catalyst in the method of the present invention is as follows.

The mixed oxide is prepared by obtaining the mixed oxide by mixing the above-described titania and silica. Simply mixing the oxides physically does not result in a mixed oxide exhibiting catalytic activity. In order to obtain a chemically mixed mixture, a mixture of soluble salts containing an element serving as a starting material for the mixed oxide, such as a nitrate, a sulfate, a chloride, an oxychloride, or an organic acid salt, is used. Ammonia water in aqueous solution,
By adding a basic substance such as caustic alkali or sodium carbonate, a precipitate such as a mixed hydrogel (hydroxide) or a mixed carbonate serving as a raw material of the mixed oxide is generated,
It is manufactured by filtering, washing, drying and firing.

It is manufactured by wet kneading a separately prepared hydrogel, carbonate, or basic carbonate, drying and calcining.

Impregnated with an aqueous solution in which a soluble salt of an element to be added as a second component to one component oxide or hydroxide, dried,
It is manufactured by firing.

The mixed oxide is a combination of two or more oxides selected from the group described above, excluding the combination of the binary mixed oxide of silica and alumina from the combination. . Here, ternary combinations such as, for example, silica-alumina-chromia are included in the scope of the present invention.

For the composition of the mixed oxide, the optimum composition should be selected for each combination, but in the case of the binary mixed oxide, 1 /
A range from 10 to 10/1 is usually chosen as a preferred range.

In the preparation of the catalyst, the mixed hydrogel powder is usually tableted or the mixed hydrogel paste is extruded, and the mixture is calcined at a temperature of 400 to 700 ° C. to be subjected to a reaction as a catalyst.

The reaction of isobutene with ammonia according to the method of the present invention, the presence of the above catalyst, reaction temperature 200 to 400 ° C., in the range of preferably 250 to 350 ° C., a reaction pressure 10kg / cm ² ~300kg /
Performed in cm ² .

The value of the molar ratio (C ₄ / NH ₃ ) of isobutene or t-butyl alcohol to ammonia to be subjected to the reaction is 2/1 to 1/10, and usually the range of 1/1 to 1/4 is often used.

The feed rate of the reaction mixture of isobutene or t-butyl alcohol and ammonia to the catalyst layer is 200 to 10,000 hr ^-1 in GHSV (NTP conversion, gas space velocity), usually 500 to 300 hr.
It is in the range of 0hr- ¹ .

As the reactor, an ordinary fixed bed or a fixed-bed multitubular reactor is used.

〔Example〕

 Hereinafter, the present invention will be described with reference to examples.

Example 1 Titanium tetrachloride was dropped into ice water with stirring to obtain an aqueous hydrochloric acid solution of titanic acid. Water glass No. 3 (JIS
No.-3) was added, and the pH was adjusted by further adding aqueous ammonia to precipitate a mixed hydrogel of titania and silica.
After sufficiently washing the precipitate with water, the precipitate was separated by filtration to obtain a paste-like substance of a mixed hydrogel. This paste is extruded (2m / mΦ
× 3 m / m), dried at 120 ° C. for 6 hours, and calcined at 500 ° C. for 6 hours in an air atmosphere to prepare a catalyst. The chemical analysis value of the catalyst is
A composition of _{SiO 2 72wt% Ti O 2 28wt} %, BET surface area 210
in m ² / g, pKa-5.6 in a test by Hammett indicator, pKa
It was found that the indicator of -3.0 showed an acidic color and had a strong acid point.

A catalyst made of SUS-316L having an inner diameter of 1 inch was charged with 50 ml of the present catalyst, and heated to 265 ° C. from the outside in a sand fluidized bath.

A mixture of isobutene and ammonia in a molar ratio (C ₄ / NH ₃ ) = 1/2 was supplied to the reactor at GHSV = 2000 hr ⁻¹ and the reaction pressure was 10
The reaction was performed at 0 kg / cm ² .

The reaction product was collected in a cooling trap and quantitatively analyzed by gas chromatography using a conventional method. As a result, the target product was obtained with a conversion of isobutene of 19% and a selectivity of t-butylamine of 96%. The by-product of the isobutene polymer was very small, and no rapid decrease in catalytic activity was observed.

Example 2 Ammonia water was dropped into a mixed aqueous solution of orthotitanic acid aqueous solution and zirconium oxychloride to obtain a precipitate of a mixed hydrogel of zirconia and titania. The precipitate was washed, separated by filtration, dried at 120 ° C., finely pulverized, added with a small amount of graphite, and then tablet-molded to form 3 m / mΦ × 3 m / m.

This was calcined at 500 ° C. in an air atmosphere to produce a catalyst.
The catalyst composition is zirconia 40wt%, titania 60wt%, BE
It was confirmed that the Hammett indicator having a T surface area of 200 m ^{2 /} g, pKa = −3.0 and pKa = −5.6 had an acidic color and was strongly acidic.

50 ml of the catalyst was charged into the reaction tube of Example 1, and heated to 270 ° C. from outside with a fluidized sand bath. A mixture of isobutanol and ammonia at a molar ratio (C ₄ / NH ₃ ) of 1 / 2.5
It was supplied to the reactor at GHSV = 2000 hr ⁻¹ and reacted at a reaction pressure of 105 kg / cm ² .

The reaction product was collected in a cooling trap and quantified by gas chromatography according to a conventional method. As a result, the target product was obtained with a conversion of isobutene of 21% and a selectivity of t-butylamine of 95%.

(Examples 3 to 11) Using the same reactor as in Example 1, the reaction was carried out by changing the catalyst used in the same reaction method in various ways. Table 1 shows the obtained results.

[Effects of the Invention] According to the method of the present invention, t-butylamine can be obtained at a high reaction rate and a high selectivity from isobutene or t-butyl alcohol and ammonia directly in a single-stage reaction.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) C07C 209/00-211/65 C07B 61/00 B01J 21/06 B01J 21/08

Claims (1)

(57) [Claims] 1. A method for producing tertiary butylamine, which comprises reacting isobutene with ammonia to produce tertiary butylamine in the presence of a mixed oxide of silica and titania as a catalyst.