DE2715667A1 - 1,4-Butane-diol prodn. by hydrogenolysis of maleic anhydride - or maleic or fumaric acids, over a mixed metal catalyst on silico-acetate carrier - Google Patents

Abstract

Prodn. of 1,4-butanediol (I) comprises hydrogenolysis of maleic anhydride, maleic acid and/or fumaric acid over a catalyst which is a mixt.of a Gp. 7b and a Gp. 8 Pt-metal (or their cpds.) supported on a silico-acetate, or its mixt. with silicic acid, as carrier. The carrier is made by treating a silicate, specifically of Mg, Ca, Zn, Ni, Co, Sr, Mn or Cd with acetic acid, and is then impregnated esp. with a soln. of Pt-metal acetate and perrheric acid in acetic acid, to give a compsn. contg. 0.1-50 wt. % active substances. (I) is an intermediate for poly(butylene terephthalate). The compsn. is resistant to abrasive losses in continuous processes; yield is imporved with reduction in by-products, specifically succinic acid, formation; and the catalyst has excellent resistance to O2-contg. gases.

Description

The subject of the invention is a single-stage, catalytic process

drive to the production of butanediol (1.4) from maleic anhydride, Maleic acid, fumaric acid or mixtures of these compounds.

Butanediol- (1.4) is used, for example, as a preliminary product for production of polyester fibers; it is butanediol (1.4) with terephthalic acid at increased Temperature converted to polybutylene terephthalate in the presence of catalysts.

Processes for the preparation of butanediol (1.4) are already known.

In particular, it is known to maleic anhydride, or maleic acid to hydrogenate their mixtures in one stage to give butanediol- (1.4), in the presence of catalysts which simultaneously contain elements of group VII b or their compounds and contain Group VIII elements or their compounds.

Although this process in batch operation yields of almost 94% d. Th. Supplies, but the continuous development prepares certain things Trouble. These difficulties are generally less of a one-off nature too low performance of the tableted catalyst used in continuous operation, but rather on the occasional insufficient mechanical strength of the catalyst tablets traced back.

This requires a certain amount of time, especially in continuous operation (> 300 hours) Abrasion and thus discharge of catalytically active components and carrier material, which not only affects the economy, but also problems with the apparatus (e.g. valve blockages).

It has now been found that by using certain carriers this older problems are resolved and also, surprisingly, the yields in the continuous hydrogenation compared to the last-mentioned process can be increased.

The present invention therefore relates to a method to the Production of butanediol (1.4) by hydrogenolysis of maleic anhydride, maleic acid, Fumaric acid or mixtures thereof in the presence of a catalyst which is a mixture a Group VIIb element or one of its compounds with a platinum metal of group VIII or one of its compounds, characterized in that that the catalyst support is a silica acetate or its mixture with silica used.

The new process differs from the older one mentioned above Process in that the formation of by-products is suppressed even further and that the abrasion occasionally observed there during prolonged operation of the catalyst is completely absent.

What is particularly surprising here is the fact that by applying of the catalysts on the silicone acetate carrier used according to the invention still one further increase in the selectivity of butanediol (1.4) can be achieved, the has a positive effect, especially with longer continuous operation, and the profitability of the method compared to the older method further improved. The application on the new carrier materials also has a stabilizing effect Effect on the performance and increases the life of the catalysts compared to the described earlier. This is crucial for continuous technical operation Significance and necessitates a technical progress of the present process compared to the older one.

Contain the catalysts used in the present process both elements or compounds of elements of Group VII b and platinum metals of group VIII of the periodic table or their compounds, including mixtures of elements of one group with connections of elements of the other group. Manganese and rhenium from group VII b, as well as ruthenium, are particularly suitable Rhodium, palladium, osmium, iridium and platinum as group VIII platinum metals. Rhenium, palladium and platinum are preferably used.

The carriers can be shaped in any way, for example as granulates, pellets, tablets, extruded parts, saddle bodies, Rings or honeycomb tubes are present; i-m alrgeMeSnen granulates are preferably used. The size of the granules is generally 1-10 mm, preferably between 3 and 6 mm.

According to the invention, silicone acetates are used as carriers, preferably those bivalent metals are used. In particular, the silicone acetates are as follows Metals suitable: magnesium, calcium, strontium, zinc, manganese, nickel, cobalt, cadmium. But also silica acetates of other divalent elements such. B. the rare earths come in question. They are generally produced by treating a metal silicate with acetic acid or acetic acid / water. This treatment is carried out as long as until the carriers are stable against acetic acid, i.e. until practically by acetic acid no more metal salt is dissolved.

A suitable carrier is obtained, for example, in the following way: Commercially available magnesium silicate, e.g. a mineral of the following composition: 56 - 60% SiO2 0.5 - 1.3% Fe2O3 22 - 26.5% MgO 0.2% Ti02 1.2 - 3.5% A1203 2.5% CO2 1.9 - 4.3% CaO 1% Na2O + K20 is mixed with acetic acid, acetic acid / water or acetic acid / methanol treated. After this treatment, a catalyst support and its composition are obtained the following is: 68.5% SiO2 14% MgO 13.4% CH3COOH (calculated as acetate) 3.6% Al203 0.5% Fe203 Its pore volume is between 0.7 and 1.2 ml / g, its BET surface area between 150 - 220 m2 / g and its bulk density between 0.4 and 0.6 g / ml. Corresponding can also be made from other natural or synthetic silicates, preferably the silicates divalent metals, the corresponding silicone acetates produce.

By applying the catalytically active elements of groups VIIb or VIII in the form of their compounds on the carrier thus prepared the supported catalysts prepared, one the compounds more or less largely, possibly down to the elements. The amount of catalytic active substances is generally between 0.1 and 50% by weight of the total mass of the supported catalyst. The amount of the inert material (carrier) is generally within a range between 99.9 and 50% of the total mass of the supported catalyst.

The ratio of Group VIII platinum elements to the elements of group VII b is between 99: 1 and 1:99, preferably between 10: 1 and 1: 10.

As compounds of the mentioned catalytically active elements come for example in question: the oxides, oxide hydrates, carbonates, nitrates, borides, carboxylates (such as acetates, propionates, butyrates), chelates of 1,3-diketo compounds (e.g. Enolates such as acetylacetonate, benzoylacetonate, acetoacetic ester compounds) especially the carboxylates, acetylacetonates, oxides and oxide hydrates are suitable. From technical and economic reasons is the use of rhenium as potassium perrhenate or Rhenium heptoxide and the use of palladium as palladium (II) acetate or acetylacetonate particularly preferred because these products are commercially available.

The solutions of the two used to make the catalysts Compounds of elements of group VIII or VII b can separately on the carrier be applied. However, it is advantageous to combine them in a carboxylic acid to solve. But it is also possible to apply a connection to the carrier first and then open the solution of the other connection. Except carboxylic acids are also other solvents for applying the catalytically active components or solvent mixtures are suitable. z. B. acetone, acetone-water, methylene chloride, Chloroform, methanol, methanol-water or water.

Carboxylic acids are all liquid ones that can be evaporated without decomposition in a vacuum aliphatic carboxylic acids having 2 to 10 carbon atoms are suitable. Are preferred Acetic acid, propionic acid and butyric acid, but especially acetic acid.

For the production of palladium-ammonium catalysts, for example is generally a solution of a palladium carboxylate or one with carbonic acids Compound which converts into palladium carboxylate, such as palladium oxide hydrate, palladium nitrate, Palladium oxycarbonate or a salt of a 1,3-diketo compound, such as acetoacetic ester or acetylacetone together in an anhydrous or hydrous carboxylic acid applied to the support with perrhenic acid or one of its salts, namely by soaking, dipping or suspending the carrier or by spraying on. the Carboxylic acid is then dried at higher temperatures in vacuo or at Normal pressure removed. The catalyst can now be used directly; preferably but it is in the gas or liquid phase at temperatures of 15 to 200 "C. Treated reducing agents.

The reduction of the catalysts can be in the liquid phase, for example with hydrazine hydrate. However, it is advantageous for higher Temperatures, e.g. at 100 - 2000C in the gas phase, with reducing gases such as hydrogen, Reduce methanol, formaldehyde, ethylene, propylene, butene. As particularly cheap an initially strong dilution of the reducing gases with inert gases was found, like nitrogen, carbon dioxide or noble gases and one with progressive reduction resulting increase in the concentration of the reducing agent, so that the reduction for example, is terminated in pure hydrogen. The reduction of the catalysts can both in a separate device, as well as in the hydrogenolysis reactor itself take place. The reduction can go as far as the metals, but it can also only partially, i.e. up to lower valences (e.g. Re11 + Re111 +, ReV +).

The catalysts can be pyrophoric and must then accordingly be treated. A reduction of the catalyst is particularly important in these cases and the subsequent hydrogenolysis of the starting compounds to butanediol- (1,4) in one and the same apparatus from Advantage. Generally are the catalysts, however, are quite insensitive and robust. For technical operation is also of great importance in the hydrogenolysis process according to the invention, that practically no succinic acid is formed, due to its extremely low level Solubility would turn out to be easy and along with the catalyst debris would cause clogging of the apparatus or would make a further process step necessary.

For the optimal design of the method according to the invention, the Hydrogenolysis of the feedstock is generally carried out at elevated temperatures. The reaction temperatures are generally between 50 and 300 ° C., preferably in the range from 150-250 ° C. The reaction pressure is generally between 50 and 500 bar. The range from 100 to 350 bar is preferred.

The hydrogen used for hydrogenolysis is generally used in a larger stoichiometric excess. Unreacted hydrogen can be returned to the reaction as cycle gas. The response can be both be carried out continuously and discontinuously. The hydrogen comes in generally technically purely for use. Additions of inert gases, e.g. B. nitrogen, however, do not interfere with the course of the reaction. The reaction time in the inventive Procedure is generally between 5 minutes and 8 hours. E.g. it is about 1 - 6 hours if the autoclave is operated discontinuously; at continuous For work, the dwell times are in a similar order of magnitude, e.g. 0.5 - 4 Hours.

After the experiment has ended, the catalysts can easily can be expanded and used again without any noticeable loss of activity. The use of the carrier according to the invention is surprising here Insensitivity of the catalysts to oxygen or those containing oxygen Gas mixtures (air) noticeable which i. Generally allowed, the catalysts, too after a use, without storing special protective measures and without special Preparations directly, possibly to be reused elsewhere.

In the case of continuous operation in technology, in general the sump phase worked, with hydrogen and the liquid or dissolved starting materials are metered into the hydrogenolysis reactor together or separately in cocurrent.

However, trickle phase operation or countercurrent operation is also possible.

When carrying out the reaction in practice, those for hydrogenations known solvents, such as. B. dioxane, tetrahydropyran or other cyclic or open-chain ethers, such as. B.

Tetrahydrofuran or diethyl ether can be used. As a solvent Polyalkylene glycol dialkyl ethers are also suitable, e.g. B. tetramethylene glycol dibutyl ether, Tetramethylene glycol dipentyl ether, tetraethylene glycol dimethyl ether, tetraethylene glycol diethyl ether and diethylene glycol dibutyl ether or mixtures of these or other solvents. Among them, those with boiling points above 2450C have proven particularly useful.

The content of starting material in such a solution is then generally between 5 and 60%. The use of maleic anhydride, for example, has proven itself as a 20 - 40% solution in 1.4 dioxane or tetrahydrofuran. Maleic acid is also Water suitable as a solvent.

The amount of catalyst required for the hydrogenation is generally at 0.5 to 25% of the maleic anhydride, maleic acid or fumaric acid amount, if is worked discontinuously.

The reaction mixtures are generally worked up by fractional distillation.

In the discontinuous production of butanediol (1.4) has the following method is particularly effective: A solution of maleic anhydride in 1,4-dioxane is placed together with the catalyst in a high-pressure autoclave, hydrogen is added and the reaction mixture is heated. After the reaction has ended, it is cooled the catalyst is separated off and the mixture is fractionally distilled.

In the case of continuous operation, the catalyst is filled into the reactor, a solution of maleic anhydride in tetrahydrofuran is pumped in and hydrogen passed under pressure while slowly heating to the desired temperature.

After reaching the desired level in the reactor, it is continuous Reaction product removed and worked up by fractional distillation.

The following examples serve to illustrate the process.

Example 1 A naturally occurring magnesium silicate, sieved out to a grain size of 3 - 4 mm, boil with 30% acetic acid until no more magnesium acetate goes into solution. 500 g of this carrier are with a Solution of 150 g of palladium acetate and 20 g of rhenium heptoxide in 3 liters of acetic acid soaked and dried repeatedly until all of the solution is used up. Then it will be slowly increasing to 2000C temperature with hydrogen / nitrogen (1: 99) reduced.

1 liter of this catalyst is put into an approx. 2 m long stainless steel high pressure reactor introduced with an inner diameter of 5 cm. The reactor is purged with nitrogen. then 500 g of a solution are pumped in every hour at the lower end, the 175 g of maleic anhydride dissolved in tetrahydrofuran.

At the same time, hydrogen with a pressure of 260 bar is also generated added at the lower end of the reactor in an amount of 2.1 Nm3 / h. One heats inside one hour to the reaction temperature of 2100C and decreases at the upper end of the Reactor continuously from reaction product and excess hydrogen.

After separation of gas and liquid reaction product in one under Reaction pressure (260 bar) standing, separate separator is the reaction product collected and separated by distillation.

Every hour about 490 to 520 g of reaction solution are obtained, which contain approx.

Contains 30% (~ 155 g, corresponding to ~ 96.7% of theory) butanediol (1.4).

By-products are n-butanol (1.9% of theory) and smaller ones Amounts of intermediate (3-butyrolactone and succinic acid).

Butyric acid and n-butane are not found.

After a running time of 980 hours, the catalyst still has the same performance like at the beginning on; no abrasion of the carrier material is observed.

Palladium and rhenium are not detectable in the discharges.

Example 2 A commercially available calcium silicate in powder form is made with 2% kaolin mixed, tabletted and burned at 8000C. These Tablets are boiled with acetic acid 30 mg until no more calcium is in solution and after drying it is crushed to a size of 2 - 3 mm. 1000 g of this The carrier is treated with a solution of 70 g of palladium (II) acetate and 8 g of rhenium heptoxide soaked in 800 ml of acetic acid and, as described in Example 1, dried and reduced.

1000 ml of this catalyst, which contains 3% palladium and 0.6% rhenium, are placed in the apparatus described in Example 1. You flush with nitrogen then with hydrogen and dosed from the top of the apparatus with a Dosing rate of approx. 50 g / h a solution of 175 g of maleic anhydride in Dioxane until the reactor is 90% full.

At the same time, hydrogen is introduced at the lower end of the apparatus (approx. 1.9 Nm3 / h) and the reaction pressure is adjusted to approx. 250 bar. Within a Hour is heated to 205 "C. But excess hydrogen is at the top of the reactor removed while the liquid reaction product at the bottom of the reactor exit.

Approx. 490-515 g of reaction solution are again obtained per hour, the contain approx. 30.3% (corresponding to 97% of theory) butanediol (1.4).

In this experiment, too, after more than 600 hours of running time, neither a drop in the catalytic converter output or a discharge of support or catalytic converter material observed.

Example 3 500 ml of tangan silicate with a grain size of 2 - 3 mm are mixed with 30 % acetic acid boiled until no more manganese goes into solution.

The dried carrier weighs 715 g (bulk density 1.43 g / ml) and has a pore volume of 0.59 ml / g. It is mixed with a solution of 38.7 g of palladium (II) acetate and 5.7 g of rhenium heptoxide soaked in 400 ml of glacial acetic acid and under vacuum at 600C Nitrogen dried.

Then at 2500 with hydrogen / nitrogen (1:99) 24 Hours reduced. The finished catalyst contains 2.5% Pd and O.6% Re.

500 ml of the catalyst are poured into the apparatus described in Example 1 introduced and the experiment, as described there, initiated.

From the lower end of the reactor 500 g of a solution per hour pumped in, which contains 140 g of maleic anhydride and 35.2 g of succinic acid dissolved in tetrahydrofuran.

At the same time, hydrogen at a pressure of 165 bar, too from the lower end of the reactor, added (about 2.2 Nm3 / h) and within a The reactor is heated to 2120C over a period of 70 minutes.

Excess hydrogen is released after passing through the apparatus liquid reaction product separately, as described in Example 1.

About 480-510 g of reaction solution are obtained per hour, which is on average Contains 27.5% butanediol (1.4). That corresponds to an average yield of about 89% d. Th.

After 430 hours of operation, the catalyst is practically still the same performance (~ 88% of theory yield). In the discharge neither rhenium, Palladium still manganese (from the carrier) detected.

Example 4 5 g of the catalyst described in Example 1 become with 100 ml of dioxane, 39.2 g of maleic anhydride, 5.0 g of succinic acid and 4.9 g of fumaric acid placed in a II shaking autoclave. 195 bar of hydrogen are injected and the system is heated with shaking (approx. 80-90 movements per minute) to 2300C and leaves for 4 hours react.

It is then cooled, let down and the reaction mixture, after filtering off from the catalyst in air, analyzed: 147 g of reaction solution contain 41 g of butanediol (1.4) (approx. 91% of theory).

With practically the same result, the catalyst is used 11 more times used under the same test conditions without a drop in performance is to be observed.

Claims (10)

Process for the preparation of butanediol- (1.4) Patent claims 0 Process for the production of butanediol (1.4) by hydrogenolysis of maleic anhydride, Maleic acid, fumaric acid or mixtures thereof in the presence of a catalyst which a mixture of a Group VIIb element or one of its compounds with a Group VIII platinum metal or one of its compounds, thereby characterized in that a silicone acetate or its mixture is used as the catalyst support used with silica. 2. The method according to claim 1, characterized in that the Manufactures silicone acetate carrier by treating a silicate with acetic acid. 3. The method according to claim 1 and 2, characterized in that one a divalent metal silicone acetate is used. 4. The method according to claim 1-3, characterized in that one the silicon acetate of magnesium, calcium, zinc, nickel, cobalt, strontium, manganese or cadmium is used. 5. The method according to claim 1-4, characterized in that one the catalytically active components as solutions in one Carboxylic acid, Applying water, acetone, methanol or methylene chloride to the support. 6. The method according to claim 1-4, characterized in that one an acetic acid solution of the Group VIII platinum metal acetate with perrhenic acid applied to the support and the acetic acid by drying higher temperatures removed in vacuo and the catalyst then with reducing agents treated. 7. The method according to claim5, characterized in that one liquid aliphatic carboxylic acid with 2 to 10, which can be evaporated without decomposition in a vacuum Carbon atoms used. 8. The method according to claim 1-7, characterized in that one the amount of the catalytically active substances between 0.1 and 50 percent by weight the total mass of the catalyst selects. 9. The method according to claim 1-8, characterized in that one the reaction temperature between 50 and 300 "C selects. 10. The method according to claim 1-9, characterized in that one selects the reaction pressure between 50 and 500 bar.