DD257972A1 - METHOD FOR PRODUCING A HYDRAULIC CATALYST - Google Patents

Abstract

Process for the preparation of a hydrogenation catalyst. The object is the preparation of an improved catalyst for the hydrogenation of butynediol in the continuous stirred reactor. The task of developing a production method for a catalyst with higher selectivity was achieved by filling nickel from water-soluble nickel compounds with sodium carbonate in quantities together with SiO 2 until 70 to 75% of the nickel can be extracted from the precipitate. Before or after the reduction of the catalyst, doping with molybdenum and copper takes place. The catalyst makes it possible to suppress by-product formation in the hydrogenation largely.

Description

The catalyst thus prepared is used in the form of powder in the hydrogenation of butynediol in the continuous stirred reactor. It is favorable if the catalyst is doped before its reduction with the components molybdenum and copper. The catalyst prepared according to the invention has a significantly higher selectivity than comparable known catalysts and can be safely handled in a stabilized form in air. The use of the catalyst according to the invention makes it possible to safely control the most advanced hydrogenation processes (2-stage hydrogenation) in the first hydrogenation stage because of the low conversion-selectivity sensitivity of the catalyst without requiring a high level of control. The yield of butanediol can be significantly increased by using the catalyst according to the invention.

embodiments

Example 1 (comparative example)

A continuously operated stirred laboratory reactor with suspended known nickel-supported catalyst (40% Ni on SiO ₂ ) (10 kg of catalyst) was charged with 650 ml / h of a 35% butynediol solution. At a temperature of T = 80 ⁰ C and a pressure of ρ = 1 MPa, a hydrogenation product was removed, whose organic constituent had the following composition:

(GC analysis)

Butynediol 5.4Ma .-%

Butenediol 82.5Ma .-%

Butanediol 2.5Ma .-%

Hydroxybutyraldehyde 8.4% by mass

Acetals 1.2Ma .-%

Example 2 (comparative example)

A continuously operated laboratory stirred reactor with suspended known nickel support catalyst (40% Ni on SiO ₂ ) (30 g catalyst) was fed 800 ml / h of a 35% aqueous butynediol solution. At a temperature of T = 85 "C and a pressure of P = 1 MPa, a hydrogenation product was taken off whose organic constituent had the following composition:

(GC analysis),

Butynediol 0Ma .-%

Butenediol 56.5Ma .-%

Butanediol 20.8Ma .-%

Hydroxybutyraldehyde 13.1% by mass

Acetals 9.6% by mass

Example 3 Inventive Example Catalyst Preparation

To 7.81 of a Na ₂ O ₃ solution, 4.51 of a waterglass solution (SiO ₂ content 200 g) are added, the mixture is heated to 60 ° C. and nickel nitrate solution is slowly added. The addition of nickel nitrate solution was continued until the formed precipitate had an amount of nickel extractable with NH ₄ HCO ₃ solution of 72% of the total nickel content. To determine the extractable nickel content, the precipitation was interrupted in each case and a sample of about ₃ g of solid with 30 g NH ₄ HCO ₃ in about 150 ml of water for 10 minutes at 9O ⁰ C maintained. The solution was filtered and the content of nickel was determined in the filtrate and in the remaining precipitate. The precipitation was terminated at an extractable nickel content of 73.7% of the nickel in the precipitate. After washing and drying the precipitate, a carbonate content of 7.3%, calculated as CO ₂ was exhibited, contained with a solution containing 70g of ammonium molybdate and 54g of copper acetate, impregnated, dried and reduced for 8 hours under a hydrogen stream at 400 ⁰ C. The finished catalyst had a SiO ₂ : Mo mass ratio of 1: 0.19 and a SiO ₂ : Cu mass ratio of 1: 0.08. 86% of the nickel present in the catalyst was in metallic form. Catalytic testing

In a stirred reactor, 28 kg of butynediol per kg of catalyst in the reactor per hour were continuously metered (35% aqueous butynediol). At a temperature of 80 ⁰ C and a pressure of 1 MPa, a hydrogenation product was removed, the organic constituent of which had the following composition:

(GC analysis)

Butynediol 3.1% by mass

Butenediol 91.2Ma .-%

Butanediol 5.2% by mass

Hydroxybutyraldehyde 0.3Ma .-%

Acetals 0.2Ma .-%

Example 4 (Inventive Example) Catalyst Preparation

The preparation of the catalyst for Example 4 is carried out analogously to that of Example 3. However, the doping with molybdenum and copper was carried out only after the reduction of the catalyst.

Catalytic testing

In a stirred reactor, 10 kg of butynediol (as a 35% strength aqueous solution) were metered in per hour per kg of catalyst present in the reactor. At a temperature of 85 ° C and a pressure of 1 MPa, a hydrogenation product was removed, the organic constituent of which had the following composition:

(GC analysis)

Butynediol 0Ma .-%

Butenediol 69.6Ma .-%

Butanediol 25.7% by mass hydroxybutyraldehyde 3.3% by mass

Acetals 1.4Ma .-%

A comparison of the examples shows that the catalyst prepared according to the invention provides substantially fewer by-products such as hydroxybutyraldehyde and acetals. The further hydrogenation of the products in a trickle reactor enables a higher yield of butanediol than in the known catalyst systems.

Claims (1)

Invention claim: A process for the preparation of a hydrogenation catalyst for the continuous production of butane-1,4-diol in the stirred reactor by co-precipitation of active component and carrier, characterized in that nickel salt solution is added to an aqueous solution of water glass and sodium carbonate kept at 60 ⁰ C until from the Precipitate with excess ammonium bicarbonate solution at about 90 ° C in about 10 minutes 70-75% of the nickel contained in the precipitate extract and the precipitate after washing and drying a carbonate content, calculated as carbon dioxide, from 7.0 to 8.5% , the dried precipitate before or after a treatment at higher temperatures in a hydrogen stream, in which more than 75% of the nickel present in the precipitate are converted into the metallic form, with an aqueous solution containing copper salts and molybdenum salts, until in the catalyst a SiO ₂ : Cu mass ratio of 1: 0.1 to 0.5 and a SiO ₂ : Cu mass ratio of 1: 0.05 to 0.3 is present. Field of application of the invention The invention relates to the preparation of an improved catalyst for the hydrogenation of butynediol in the continuous stirred reactor. " Characteristic of the known technical solutions For the hydrogenation of butyn-2-diol-1,4 (butynediol short butane to 1,4-butanediol) are supported catalysts by impregnation of a particulate carrier such as 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 O ₃ or iron oxide (DE-AS 2917018) are after deformation exclusively for the trickle-phase hydrogenation The catalysts have a comparatively low catalytic activity and a low life span Because of the strong exotherm of the reaction, the heat removal from the fixed bed reactor is difficult to control, so that on an industrial scale only relatively impure hydrogenation products with The removal of heat is easily achieved by hydrogenation over Raney nickel in the stirred reactor, but these catalysts prove to be comparatively unselective under the usual conditions (DE-PS 858094) Although significantly improve selectivity, in the proposed for these catalysts discontinuous hydrogenation processes (DE-OS 2926641), however, they show low effectiveness. These catalysts also require cumbersome manufacture and handling by the user. If the discontinuous hydrogenation in the stirred reactor is followed by high-pressure hydrogenation in the trickle reactor on one of the abovementioned fixed-bed catalysts, relatively pure products are obtained, but the yield is only about 90%. This procedure is also very expensive. When using commercially available supported catalysts and nickel as the hydrogenation in continuous stirred reactors, this effort is greatly reduced (DD-PS 219184). However, these nickel-supported catalysts require narrow sales ranges for butynediol (about 95% conversion), so that a sufficient selectivity of the process is achieved. The yield is not significantly above 90% in these catalysts, despite the high control effort required. Object of the invention The aim of the invention is an improved production process for catalysts for Butindiolhydrierung that allow a high yield of butanediol. The nature of the invention The invention has for its object to develop a process for the preparation of a Butindiolhydrierkatalysators that provides a catalyst with high selectivity with respect to the formation of butanediol. The object is achieved by co-precipitation of active component and carrier according to the invention in that nickel salt solution is added to an aqueous solution of water glass and sodium carbonate kept at 6O ⁰ C until the precipitate formed with excess ammonium bicarbonate at about 90 ° C within 10 minutes 70 to 75% of the nickel contained in the precipitate and the precipitate after washing and drying has a carbonate content, calculated as carbon dioxide, of 7.0 to 8.5%, the dried precipitate before or after a treatment at higher temperatures in the hydrogen stream in which more than 75% of the nickel present in the precipitate is converted into the metallic form, treated with an aqueous solution containing copper salts and molybdenum salts, until in the catalyst a Si0 ₂ : Mo mass ratio of 1: 0.1 to 0.5 and a SiO ₂ : Cu mass ratio of 1: 0.05 to 0.3 is present.