DD274982A1 - PROCESS FOR PREPARING A CATALYST FOR BUTINDIUM 1,4-HYDROGENATION - Google Patents

Abstract

The invention relates to the preparation of an improved catalyst for the hydrogenation of butynediol-1,4 in the continuous stirred reactor. The object of developing a production process for a catalyst with high catalytic activity and high selectivity was achieved by charging a solution containing palladium complex salt to a spray-dried microspherical support of defined texture, grain size distribution and surface properties. The carrier is thermally treated before and after this traction and then cooled with hydrazine solution.

Description

Object of the invention

The aim of the invention is a preparation process for a catalyst for butynediol hydrogenation, which allows a high yield of butanediol with little effort.

Explanation of the essence of the invention

The invention has for its object to develop a process for dio production of a Pd catalyst for butynediol hydrogenation, which provides a catalyst with high catalytic activity and high selectivity with respect to the formation of butanediol.

The object of the preparation of a catalyst for Butindiolhydrierung that is used in the continuous medium pressure hydrogenation to butanediol in the stirred reactor by impregnation of a porous support with palladium salt solution according to the invention is achieved in that the carrier by spraying and simultaneous drying of an aqueous suspension, the nitric acid and boehmite in the mass ratio vo.i at least 1: 100 and one or more at higher temperatures decomposable or combustible compounds in amounts of not more than 10 Ma.- ¹ '-., Based on the amount of boehmite contains, prepared and then annealed at higher temperatures in an oxidizing atmosphere is a BET surface area of at least 15OmVg and a pore volume of at least 0.7cm ³ / g, thereof a pore volume in the pore radius range of 100 to 1000 angstroms of at least 0.2cm ³ / g and a pore volume in the pore radius range above 1000 angstroms also at least 0.2cm ³ / g, and this carrier which has a microspherical shape with a particle size distribution of less than 35 .mu.m in the particle size range and at least 35 .mu.m in the particle size range of 40 to 6. ' lpm has a particle diameter, is impregnated with a solution containing palladium complex salt until it has a palladium content of 0.1 to 5 mass%, preferably 0.5 to 1 mass%, after treating ii oxidizing atmosphere at elevated temperatures, subsequently treated with aqueous hydrazine solution in excess and then dried until it has after activation at 100 ° C Acidity, measured when covering the palladium with CO, from 150 to 300 μΜοΙ NH ₃ / g of catalyst and after reduction in a stream of hydrogen at 100 ⁰ C. has a palladium dispersity of Fco = 0.05 to Fco = 0.4.

As a decomposable or combustible compounds z. As urea or polyvinyl alcohol used. The catalyst prepared according to the invention makes it possible, contrary to the known experience with a palladium catalyst, to obtain butanediol in high yield even without expensive doping. A significant advantage of this catalyst is that butinediol is hydrogenated continuously even at medium pressure conditions in the stirred reactor. It can either be obtained at low levels of butanediol of sufficient quality or, at high loads, the minor by-product quantities formed are removed in a second stage at medium pressure, with very high purity butanediol obtained wild.

Compared to the most advanced methods for Butindiolhydrierung - continuous hydrogenation in the stirred reactor with suspended nickel catalyst and subsequent hydrogenation in the high pressure reactor - allows the use of the catalyst according to the invention a significant reduction in the cost of equipment, raw materials and energy.

embodiments

Example 1 (Verp'eichsbeispiel)

catalyst

A nickel supported catalyst was prepared according to DD-PS 219 184 by coprecipitation of nickel and carrier: A Na ₂ CO ₃ solution was added to a waterglass solution, heated to 6O ⁰ C and nickel nitrate solution. After filtration, the precipitate was washed, dried and reduced in a stream of hydrogen at 500 ^° C. for 8 hours. The finished catalyst had a nickel content of 40%.

Catalytic test:

A continuously operated stirred laboratory reactor with suspen.viertem nickel support catalyst (10g catalyst) were 650rnl / h fed to a 35% Butindioliösung. At a temperature of 8O ⁰ C and a pressure of 1 MPa, a hydrogenation product has been removed, which had organic part of the following composition:

Butynediol 1 / l: 5.4% by mass Butenediol-1,4: 82,5Ma .-% 1,4-butanediol: 2.5mA .-% y ^: hydroxybutyraldehyde: 8,4Ma .-% acetals: 1,2Ms -%

This hydrogenation product was hydrogenated in a fixed bed reactor at 10 ° C and a pressure of 24.5 MPa on a supported nickel catalyst. The organic portion of the obtained crude butanediol had the following composition:

butanediol 92.7% by mass γ-Hydroxybutyraldehyde 0.5mA .-% acetals 0.5mA .-% butanol 3.6mA .-% Methanol and others 2.7% by mass ingredients

Example 2 (Inventive Example)

catalyst

An aqueous suspension containing nitric acid and boehmite in the mass ratio of 3: 100 and 2% urea, based on the amount of boehmite was sprayed and thereby dried and then annealed in air until a BET surface area of 185m ² / gundein pore volume of 0 , Pore volume in the pore radius range of 100 to 1000A = 0.24 cm ³ / g, pore volume in the pore region with radii over 1000A = 0.22 cm ³ / g). The microspherical carrier had the following particle size distribution:

<40μπι grain diameter = 48Ma .-% 40 to 63 pm grain diameter = 44 Ma .-%

After cooling, the support was impregnated with a solution containing tetramminepalladium (II) nitrate and treated in an oxidizing atmosphere at elevated temperatures. The palladium content of the catalyst was 1 mass%. After treatment with an excess of aqueous hydrazine solution, the catalyst was dried until it after activation at 100 ° C an acidity, measured by covering the palladium with CO, of 210pmol NH ₃ / g catalyst possessed and after reduction in a stream of hydrogen at 100 ⁰ C. Palladium dispersion of Fco = 0.24 had. Catalytic testing

In a stirred reactor, 3 kg of butynediol per kg of catalyst per hour in the reactor (35% aqueous butynediol solution) were metered in continuously. During the hydrogenation, the following conditions were observed:

Hydrogen pressure: 2 MPa Temperature: 6O ⁰ C pH of the reaction solution: about 10

The volume of the dosed 35% butynediol solution was equal to the volume of the hydrogenation solution removed from the stirred reactor. During the entire duration of the hydrogenation, the catalyst contained in the hydrogenation solution removed from the reactor was continuously separated off and returned to the Rf.aktor. By metering fresh catalyst into the reactor and withdrawing about equal amounts of catalyst from the reaction system, a butindole conversion of 100% and a content of butenediol in the removed hyaline product of about 0.1% by mass, based on the organic ingredients, were consistently maintained. The organic constituent of the hydrogenation product had the following composition:

Butynediol: not detectable butenediol: 0.1% by mass

Butanediol: 98.0Ma .-% ^ Hydroxybutyraldehyde: 0.4Ma .-%

Acetals: not detectable butanol: 0.3Ma .-%

Methanol and other ingredients: 1.2Ma .-%

A comparison of the examples shows that a significantly higher yield of butanediol is achieved when using the catalyst according to the invention despite one-stage hydrogenation. The quality of the resulting butanediol is also much better.

Claims (1)

A process for the preparation of a catalyst for Butindiol-1,4-hydrogenation, which is used in the continuous medium pressure hydrogenation to 1,4-butanediol in the stirred reactor, by impregnation of a porous support with palladium salt solution, characterized in that the carrier by spraying and simultaneously drying a aqueous suspension containing nitric acid and boehmite in a mass ratio of at least 1: 100 and one or more at higher temperatures decomposable or combustible compounds in amounts of not more than 10Ma .-%, based on the Böbmitmenge, and then annealed at higher temperatures in an oxidizing atmosphere is, until a BET surface area of at least 15OmVg and a pore volume of at least 0.7cm ³ / g, of which a pore volume in the pore radius range of 100 to 1000 angstroms of at least 0.2cm ³ / g and a pore volume in the pore radius range above 1000 angstroms of also at least 0.2 cm ³ / g, adjusted w This support, which has a microspherical shape with a particle size distribution of at least 35% by mass in the particle size range below 40 μm particle diameter and at least 35% by mass in the particle size range of 40 μm to 63 μm particle diameter, is impregnated with a solution containing palladium complex salt until dissolved Treating in oxidizing atmosphere at higher temperatures, a palladium content of 0.1 to 5 wt .-%, preferably 0.5 to 1 wt .-%, then treated with aqueous hydrazine solution in excess and then dried until it after activation at 100 ⁰ C acidity values, measured by covering the palladium with CO, of 150 to 300μΓηοΙ NH ₃ Zg catalyst and after reduction in a stream of hydrogen at 100 ⁰ C has a Pd disperse ratio of Fco = 0.05 to Fco = 0.4. Field of application of the invention The invention relates to the preparation of an improved catalyst for the continuous hydrogenation of butynediol-1,4 to 1,4-butanediol in the stirred reactor. Characteristic of the known technical solutions For the hydrogenation of Butindio! are fixed bed catalysts by impregnation of a lumpy support, for. B. Al ₂ O ₃ , with nickel salt solution and subsequent decomposition of the nickel salt to the oxide and subsequent reduction of the nickel are known. These supported catalysts often contain besides nickel other doping components such as copper and manganese (DD-PS 98902). Both these and precipitation catalysts based on nickel, copper, molybdenum and manganese oxide without support (DE-OS 2536273) or with Al ₂ Oi or iron oxide (DE-AS 2917018) are after deformation exclusively for the trickle-phase hydrogenation used by Butindiollösungen in high pressure fixed bed reactor. The catalysts mentioned show low catalytic activity and short life. Their use on an industrial scale leads, partly influenced by the poor heat removal from the fixed bed reactors, to impure hydrogenation products with low yields of butanediol. Although suspension catalysts which are used in the batchwise hydrogenation of butynediol in the stirred reactor, allow advantages in the heat dissipation. The selectivity of such catalysts as Raney-Nickei (DE-PS 858094) is nribst after doping with molybdenum compounds odor other components (OE-OS 2926641) is insufficient. The high content of by-products formed such as γ-hydroxybutyraldehyde and acetates must be reduced in a subsequent high-pressure hydrogenation of the fixed-bed catalysts mentioned above (US-PS 3449445). Palladium-supported catalysts are described as being particularly unselective in the literature and lead to more than 40% by-products in the hydrogenation of butynediol to butenediol if they are not provided with activity-damping dopants such as zinc, cadmium or lead (British Patent 1,504,187, French Pat. No. 2,277,873) ). With the use of Rutheniunv / palladium catalysts in the discontinuous medium-pressure hydrogenation was trying to remove the by-products formed by a high content of ruthenium in the catalyst under the mild conditions of discontinuous medium-pressure hydrogenation (US-PS 4438285). The complicated batchwise operation and the high cost of the catalyst (ruthenium content 4%, palladium content 1%, catalyst used based on butynediol over 10%) and the use of organic solvents required for complete sutindiol conversion as well as the high propensity of ruthenium catalysts for the formation of n -Butanol fundamental disadvantages that preclude a technical use. P'jl er¬ shaped nickel-supported catalysts, which allow continuous hydrogenation in the stirred reactor, but at absolutely be observed sales of butynediol 90 to 98% only to butenediol, which must then be reacted under the known high pressure conditions to butanediol (DD-PS 219184) , However, the advantage of consistently continuous hydrogenation is achieved by a complicated and very complicated two-stage process with unsatisfactory yields of butanediol.