DE963238C - Process for the production of alcohols - Google Patents

Description

ISSUED MAY 2, 1957

F 17427 IVb j 12

has been named as the inventor

It is known that the hydration of olefins, in particular the conversion of ethylene into ethyl alcohol, can be carried out in such a way that ethylene and steam are passed ^{over catalysts at temperatures from 250 to 320 0} and under pressures such that the reactants remain in the gaseous state . The main catalyst used is phosphoric acid, which is deposited on porous supports. So you have the reaction z. B. carried out so that one has passed at 300 ⁰ and 70 atm water and ethylene in a molar ratio of 0.6 over phosphoric acid on diatomaceous earth (see US Pat. No. 2,579,601); 4.2% of the ethylene is converted in a single pass and about 80 g of ethyl alcohol are formed per 1 liter of catalyst / h. The reaction can also be carried out in a fluidized bed with the above-mentioned known catalysts, a conversion of 4.5% of the ethylene being achieved in a single pass.

With catalysts, which make it possible with a single throughput under otherwise identical conditions To achieve a higher conversion of the olefin would be a corresponding reduction in price the technical implementation arise because the capacity of the plant would grow and above all would be saved in thermal energy to the Äthylenbzw. Amount of water to .reaction temperature to bring.

It has now been found that silicophosphoric acids or salts of silicophosphoric acids in particular suitable catalysts for the catalytic

Represent hydration of olefins, especially ethylene. Primarily the silicophosphoric acids are of the composition H ₂ -Si (PO ₄ ). ₂ or their salts Me ¹ ,, Si (PO ₄ ) _{2 are} suitable for this.

Are ethylene and water vapor in constant ratio and under the same conditions of the Pressure and temperature over equal volumes of the catalysts listed in the table below led, the specified amounts of alcohol are formed in the same times. The yield obtained by the process of US Pat. No. 2,579,6oi (phosphoric acid on diatomaceous earth) is used with ioo.

catalyst

H ₃ PO ₄ on diatomaceous earth (US Pat. No. 2,579,6oi)

free H ₂ Si (PO ₄ ) ₂

free Si, (PO ₄ ) ₄

Aluminum salt of H ₂ Si (PO ₄ ) ₂

Aluminum salt of H ₂ Si (PO ₄ ) 2, made from active aluminum silicate and

H ₃ PO ₄

the H ₂ Si (PO ₄ ) ₂

Iron salt of H ₂ Si (PO ₄ ) ₂

against it

acidic aluminum phosphate (Al H) ₃ (PO ₄ ) ₂

acid cerium phosphate

Yield to. Ethyl alcohol

IOO

151

III

160

170

178
175

For the production of the salts of the silicophosphoric acid, freshly precipitated silica gel is used

Neten amount of phosphoric acid given and the metal hydroxide in question, produced z. B. from the nitrate with ammonia added. The salt solution or suspension is then thickened and the catalyst formed into balls or sausages. In order to achieve a particularly high activity, it has been found to be expedient to leave part of the ammonium nitrate formed in the catalyst mass due to poor washing out during the production of the metal hydroxide. The shaped mass is then heated to a temperature higher than the reaction temperature (300 ⁰ ). z. B. to 600 °, heated, the escaping ammonium nitrate made the catalyst molded porous. One can also by absorption of phosphoric acid in active shaped silicates, e.g. B. aluminum silicate in spherical shape, and subsequent drying to produce an active aluminum silicophosphate. In contrast, adding silica gel to acidic metal phosphate results in only inactive catalysts, which consist of acidic metal phosphate mixed with Si O ₂ . The existence of the metal salts of silicophosphoric acid used as a catalyst was proven by characteristic X-ray diagrams. The use of the largest possible surface, ie the smallest possible particle size of the catalysts, is essential for good activity of the catalysts mentioned.

The inventive use of the catalysts mentioned also extends to the implementation the reaction in the fluidized bed process.

Any decrease in the activity of the catalyst is canceled out by periodic Addition of small amounts of a mixture of silicic acid ester and trialkyl phosphate in one such a ratio that the saponification taking place under the reaction conditions active silicophosphoric acid is formed.

The process according to the invention enables the addition of water to olefins in an economical manner to make advantageous manner.

example

About 2.6 l of a catalyst produced from active aluminum silicate in bead form by impregnation with phosphoric acid, which is the aluminum salt of the silicophosphoric acid SiH ₂ (PO ₄ ) ₂ , was at 300 to 310 ⁰ and 72 atm. per hour 3100 1 of ethylene and 1500 g of steam passed. 140 to 150 g of ethyl alcohol (100%) were produced per hour per 11 catalyst. In a single pass, 6.2 to 6.5% of the ethylene was converted. The resulting ethyl alcohol can be separated off as a 30 percent by weight solution through fractional condensation.

Claims (1)

90 claim: Process for the production of alcohols by addition of water to olefins at increased Temperature and elevated pressure in the gas phase in the presence of a catalyst, thereby characterized in that silicophosphoric acid or salts thereof are used as the catalyst will. © 609579/507 8.56 (609 873 4. 57)