DE102016220662A1 - Process for the preparation of at least one hydrogenated compound from a carboxylic acid derivative - Google Patents

Abstract

The present invention relates to a process for the preparation of at least one hydrogenated compound from a carboxylic acid derivative, comprising at least one step in which the carboxylic acid derivative is reacted with hydrogen in the presence of at least one catalyst, wherein according to the invention an ammonium salt of a carboxylic acid in aqueous solution is reacted with hydrogen , An advantage of the method according to the invention is that not only from a salt, the carboxylic acid itself must be recovered and cleaned consuming. The products formed in the hydrogenation are primarily alcohols. However, at least partially aliphatic or cyclic ethers, lactones and hydroxycarboxylic acids can also be formed. The reaction can be carried out, for example, in a trickle bed reactor (10). It has in the upper region a first inlet (11) for the addition of an aqueous solution of a carboxylic acid ammonium salt, which is distributed via a liquid distributor (13) over the cross section of the reactor interior. In the head area, for example, a gas inlet (12) for hydrogen is located approximately in a centric arrangement. The liquid supplied through the inlet (11) thus mixes with the gas flowing in the top and the mixture then flows downwards in the reactor (10) and enters a catalyst bed (14) arranged in the reactor. In this catalyst bed (14), the aqueous solution of the carboxylic acid salt is reacted with the hydrogen.

Description

The present invention relates to a process for the preparation of at least one hydrogenated compound from a carboxylic acid derivative comprising at least one step in which the carboxylic acid derivative is reacted with hydrogen in the presence of at least one catalyst.

In the DE 10 2010 025 167 A1 a process for the production of succinic acid is described. The resulting from the fermentation Diammoniumsuccinatlösung is freed by filtration of biomass. Subsequently, the addition of sulfuric acid and the associated lowering of the pH, the free succinic acid and formed as by-product diammonium sulfate. In the following, this solution is split into the two fractions aqueous succinic acid solution and aqueous diammonium sulfate solution in Simulated Moving Bed (SMB) chromatography. The aqueous succinic acid solution is thickened, if necessary after further purification steps. As a result, falls below the succinic acid solubility in water pure succinic acid. Disadvantages of this process are the extensive work-up steps, the use of an additional chemical (sulfuric acid), the loss of ammonia introduced into the process in the form of an ammonium salt and the need to achieve a cost-effective use of this coproduct (diammonium sulfate).

The WO 2011/123269 A1 describes a process for the preparation of tetrahydrofuran, gamma-butyrolactone and butanediol from succinic acid salts in which fermentation-derived diammonium succinate is separated after separation of the biomass in a first step by thermal treatment of monoammonium succinate in ammonia and succinic acid. The ammonia is withdrawn and can be recycled to the fermentation process elsewhere. The succinic acid can be recovered from the resulting solution by crystallization in pure and solid form. This pure succinic acid is then hydrogenated in a further step in a hydrogenation process in aqueous solution using a metal-loaded supported catalyst with hydrogen, with different products depending on the reaction conditions in different amounts, especially butanediol, tetrahydrofuran and gamma-butyrolactone. A disadvantage of this process is that the succinic acid must first be crystallized before it can then be hydrogenated in a further process step.

The Canadian patent application CA 2 657 666 describes a process in which the ammonia is recovered from a fermentatively prepared aqueous solution of diammonium succinate by reactive pressure reaction with carbon dioxide in the presence of an alcohol (ethanol). At the same time, the diester of succinic acid is formed. This can be purified by a conventional distillation and then fed to a known catalytic hydrogenation to obtain butanediol, tetrahydrofuran and / or gamma-butyrolactone. A disadvantage of this method is the use of another substance (the alcohol), which must be recovered in the following steps again. A further disadvantage is that an equipment-consuming, because under pressure, process using CO ₂ must be used to produce the succinic acid diethyl (diethyl succinate).

The object of the present invention is to provide an improved process for preparing at least one hydrogenated compound from carboxylic acid derivatives.

The solution to this problem is provided by a process for preparing hydrogenated compounds from a carboxylic acid derivative, comprising at least one step in which the carboxylic acid derivative is reacted with hydrogen in the presence of at least one catalyst, having the features of claim 1.

In the context of the present invention, it has been found that ammonium salts of carboxylic acids on suitable catalysts and under appropriate reaction conditions can be reacted with hydrogen in aqueous solution. In this case, at least in part, the previously bound as ammonium nitrogen is released in the form of ammonia. The ammonia can be removed with appropriate measures from the reaction system and optionally returned to the beginning of the process. But there is also the possibility that the ammonia is otherwise reused.

An advantage of the method according to the invention is thus that not only from a salt, the carboxylic acid itself must be recovered and laboriously cleaned, but one reacts directly in the hydrogenation of the ammonium salt of the carboxylic acid with hydrogen.

When the ammonia is (partially) recovered by the process according to the invention, this can be done, for example, by washing with water or washing out with acid or washing out with at least one part of a fermentation solution.

The products formed in the hydrogenation are primarily alcohols. However, at least partially aliphatic or cyclic ethers, lactones and hydroxycarboxylic acids can also be formed.

The reaction mixture is preferably worked up after separation of the catalyst such that at least parts of the products formed can be obtained in salable or suitable for further reactions purity. This treatment can be carried out, for example, by distillation, extractions, crystallizations and / or separations via membranes and / or other suitable measures alone or in combination.

According to a preferred development of the present invention, an ammonium salt of a monocarboxylic acid or a dicarboxylic acid is hydrogenated.

In particular, it may be an ammonium salt of a carboxylic acid selected from the group comprising acetic acid, propionic acid, lactic acid, succinic acid, adipic acid, sebacic acid and oxalic acid.

According to a preferred development of the present invention, the catalyst used for the hydrogenation is a heterogeneous catalyst with a catalyst support selected from the group comprising activated carbon, Al ₂ O ₃ , TiO ₂ , ZrO ₂ , SiO ₂ and MgO or mixtures thereof.

Furthermore, preference is given to using a supported catalyst having a monometallic active component, in particular comprising at least one element selected from Ru, Pd and Re or a supported catalyst with a bimetallic active component, in particular comprising a combination of metals selected from Ru / Ir, Ru / Rh, Re / Pd, Re / Rh.

The hydrogenation of the carboxylic acid derivative by the process according to the invention can be carried out in various reactor types. For example, come into consideration batch reactors. It may be advantageous to carry out the hydrogenation at elevated temperature and / or under elevated pressure, in particular in an autoclave. For example, a continuous stirred tank reactor (CSTR) can be used as a batch reactor.

Alternatively, one can also carry out the hydrogenation in a Trickle-Bed reactor (trickle bed reactor), wherein again different process variants are particularly advantageous. For example, in such a Trickle-Bed reactor with feed stream and hydrogen in cocurrent or with feed stream and countercurrent hydrogen can be used. Alternatively, it is also possible, for example, to carry out the process in a bubble column reactor.

Particularly preferably, in the present invention, the diammonium salt of succinic acid is hydrogenated, which has the formula H ₄ N ^{+ -} OOC-CH ₂ -CH ₂ -COO ^- NH ₄ ⁺ . The structural formula of succinic acid is shown below. (Succinic acid is abbreviated to BS in Table 1)

Succinic acid is a dicarboxylic acid of industrial importance. Succinic acid and its compounds are used, for example, in the food industry, pharmacy, cosmetics and in the textile industry. Furthermore, succinic acid is used as starting material for the production of polymers. It is advantageous for the industrial use of succinic acid that it can be produced by fermentation of carbohydrate-containing substrates by means of various microorganisms. One Process for the fermentative production of dicarboxylic acids, including succinic acid, is for example in the WO 2014/108163 A2 described. Therefore, it is advantageous in the context of the present invention to hydrogenate an ammonium salt of a carboxylic acid obtained by fermentation, in particular a diammonium succinate.

In the hydrogenation of the diammonium salt of succinic acid by the process according to the invention, depending on the reaction conditions, different products can be formed in different proportions; in particular, the corresponding alcohol 1,4-butanediol is formed upon reduction of both carboxyl groups (abbreviated to BDO in Table 1) whose structural formula is given below:

Furthermore, by partial reduction of only one carboxyl group and subsequent intramolecular ester formation γ-butyrolactone, also known under the name dihydrofuran-2-one, partly also denoted by the abbreviation GBL, which has the following structural formula:

Furthermore, when only one of the two carboxyl groups is reduced, 4-hydroxybutyric acid or 4-hydroxybutanoic acid, also γ-hydroxybutyric acid (abbreviated to GHB), whose structural formula is reproduced below, is formed:

Finally, reduction of both carboxyl groups and subsequent ring formation may give rise to tetrahydrofuran, also abbreviated to THF, whose structural formula is given below:

• 1 einen schematisch vereinfachten Längsschnitt durch einen beispielhaften Reaktor, welcher in einem erfindungsgemäßen Verfahren verwendet werden kann.

Hereinafter, the present invention will be described with reference to an embodiment with reference to the accompanying drawings. Showing:

• 1 a schematically simplified longitudinal section through an exemplary reactor which can be used in a method according to the invention.

In the 1 reproduced representation shows a simplified schematic longitudinal section through a Trickle-Bed reactor (trickle bed reactor), which is generally designated by the reference numeral 10. The reactor has an elongated, about the majority of its length, approximately cylindrical basic shape. He points in the upper portion a first inlet 11 for the addition of an aqueous solution of a carboxylic acid ammonium salt. This liquid is distributed over a liquid distributor 13 as evenly as possible over the cross section of the reactor interior. In the head region, for example, a gas inlet 12 for hydrogen is located approximately in a centric arrangement. The liquid supplied through the inlet 11 thus mixes with the above-flowing gas and the mixture then flows down the reactor and enters a catalyst bed 14 arranged in the reactor. In this catalyst bed 14, the aqueous solution of the carboxylic acid salt reacts with the hydrogen and Hydrogenated products such as, for example, alcohols, ethers, lactones or hydroxycarboxylic acids are formed.

Below the catalyst bed 14 are located in the reactor two outlets for the reaction products, namely on the one hand, a gas outlet 15 and in the lower end of the reactor 10, an outlet 16 for liquid, which has accumulated in the lower region of the reactor below the gas outlet 15. The discharged from the reactor products are then usually supplied to appropriate devices in which a further separation takes place, for example by distillation, extraction, crystallization and / or by means of separation via a membrane.

In one embodiment, the reactor 10 may be heated over its entire length by means of a suitable heater 17, such as an oven or a tracer heater.

Hereinafter, the method according to the present invention will be explained in more detail by means of concrete experimental examples.

example 1

Hydrogenation of diammonium succinate in a CSTR

1.22 g (residual moisture content: 45% by mass) of a catalyst powder from Heraeus with a loading of 4% by mass Ru / 1% by mass Ir on activated charcoal carrier were mixed in an autoclave with aqueous diammonium succinate solution (5% by mass). based on succinic acid, 12.88 g diammonium succinate in 189.45 g H ₂ O). Before carrying out the reaction, the autoclave was purged with hydrogen gas. Subsequently, the reaction mixture was brought under constant stirring by applying the hydrogen and increasing the temperature gradually to the reaction conditions of 175 bar and 180 ° C. The hydrogenation was carried out for a period of 20 h. At the end of the reaction time, the reaction system was cooled to room temperature, the catalyst was filtered off and the reaction solution was analyzed by HPLC (separating column Aminex HPX-87H from Bio-Rad with 300 × 7.8 mm; particle size carrier material 9 μm, pH range 1-3; Phase aqueous H ₂ SO ₄ , 4mM; RI detector) and GC (Agilent's HP-PONA methyl siloxane separation column 50m x 0.2mm; film thickness 0.5μm; temperature program: start 50 ° C to 70 ° C at 2 K / min, then from 70 ° C to 280 ° C at 4 K / min, keeping the final temperature of 280 ° C for 10 min; carrier gas helium; FID). An overview of selected experiments including results for the hydrogenation of aqueous diammonium succinate solutions in CSTR is shown in Table 1.

Example 2

Hydrogenation of diammonium succinate in a Trickle-Bed reactor

14.27 g (dry) of a catalyst granulate from Heraeus with a loading of 4% by mass Re / 2% by mass Pd on activated charcoal carrier were placed in a tubular reactor (/ = 39.5 cm, _inside = 7.9 mm ) built-in. The volume of the catalyst bed was about 40 ml (height of the catalyst bed h = 20 cm). Before carrying out the reaction, the reactor was thoroughly purged with nitrogen gas. The catalytic hydrogenation was carried out in continuous operation (LHSV = 0.5 h ^-1; V _Feed = 20 ^MLH-1; V _{H 2} = 20 NLh ^-1 ) with diammonium succinate solution (5.2% by mass, based on succinic acid) at 175 bar and 180 ° C. Behind the reactor, the product solution was separated from the gas stream by means of a liquid separator. Sampling took place every hour and the liquid product solution was subsequently analyzed by HPLC (separation column Aminex HPX-87H from Bio-Rad with 300 × 7.8 mm, particle size carrier material 9 μm, pH range 1-3, mobile phase aqueous H ₂ SO ₄ , 4mM; RI detector) and GC (Agilent's HP-PONA methyl siloxane separation column of 50m x 0.2mm; film thickness 0.5μm; temperature program: start 50 ° C to 70 ° C at 2K / min, then from 70 ° C to 280 ° C at 4 K / min, holding the final temperature of 280 ° C for 10 min; carrier gas helium; FID). An overview of selected experiments including results for the hydrogenation of aqueous diammonium succinate solutions in the Trickle-Bed reactor is shown in Table 1.

• Die Hydrierung des Diammoniumsalzes der Bernsteinsäure führt im CSTR überwiegend zur Bildung von γ-Hydroxybuttersäure und γ-Butyrolacton durch partielle Reduktion einer der beiden Carboxyl-Gruppen. Hingegen führt die Hydrierung im Trickle-Bed-Reaktor unter Einsatz des Katalysators 4 Ma.-% Re / 2 Ma.-% Pd auf Aktivkohleträger durch Reduktion beider Carboxyl-Gruppen hauptsächlich zum Alkohol 1,4-Butandiol.

Tabelle 1: Übersicht ausgewählter Versuche zur Hydrierung von Diammoniumsuccinat (H₄N^+-OOC(CH₂)₂COO^-+NH₄) Aktive Spezies Träger m (Kat)¹ w (BS)² X (BS)² S (BDO)³ S (GHB)³ S (GBL⁾³ S (THF)³ CSTR⁴ 5% Ru² Aktivkohle 0,66 g 5,0% 53,5% 5,24% 34,2% 0% 0,6% 4% Ru / 1% Ir² Aktivkohle 0,67 g 5,0% 45,2% 8,5% 41,2% 12,1% 0,1% 4% Re / 2% Pd² Aktivkohle 0,67 g 5,0% 38,644% 8,2% 0% 11,0% 0,7% Trickle-Bed⁵ 4% Re / 2% Pd² Aktivkohle 14,27 g 5,2% 43,8% 46,9% 0% 0,6% 0% 4% Re / 2% Pd² Al₂O₃ 24,75 g 5,2% 89,8% 5,2% 16,1% 3,4% 0% ¹Masse Katalysator (trocken) ²Massenanteil und Umsatz auf Bernsteinsäure bezogen ³Selektivität angegeben auf molarer Basis ⁴175 bar, 180 °C, Reaktionszeit = 20 h ⁵175 bar, 180 °C, LHSV = 0,5 h^-1,V̇_Feed = 20 mL h^-1,v_Kat = 40 mL,V̇_{H 2} 20 NL h^-1 Table 1 below gives the following information:

• The hydrogenation of the diammonium salt of succinic acid leads in the CSTR predominantly to the formation of γ-hydroxybutyric acid and γ-butyrolactone by partial reduction of one of the two carboxyl groups. In contrast, the hydrogenation in the Trickle Bed reactor using the catalyst leads to 4% by mass Re / 2% by mass Pd on activated charcoal carrier by reduction of both carboxyl groups mainly to the alcohol 1,4-butanediol.

Table 1: Summary of selected experiments on the hydrogenation of diammonium succinate (H ₄ N ^{+ -} OOC (CH ₂ ) ₂ COO ^{- +} NH ₄ ) Active species carrier m (cat) ¹ w (BS) ² X (BS) ² S (BDO) ³ S (GHB) ³ S (GBL ^{) 3} S (THF) ³ CSTR ⁴ 5% Ru ² activated carbon 0.66 g 5.0% 53.5% 5.24% 34.2% 0% 0.6% 4% Ru / 1% Ir ² activated carbon 0.67 g 5.0% 45.2% 8.5% 41.2% 12.1% 0.1% 4% Re / 2% Pd ² activated carbon 0.67 g 5.0% 38.644% 8.2% 0% 11.0% 0.7% Trickle Bed ⁵ 4% Re / 2% Pd ² activated carbon 14.27 g 5.2% 43.8% 46.9% 0% 0.6% 0% 4% Re / 2% Pd ² Al ₂ O ₃ 24.75 g 5.2% 89.8% 5.2% 16.1% 3.4% 0% ¹ mass catalyst (dry) ² mass fraction and conversion based on succinic acid ³ selectivity indicated on a molar basis ⁴ 175 bar, 180 ° C, reaction time = 20 h ⁵ 175 bar, 180 ° C, LHSV = 0.5 h ^-1 , V̇ _Feed = 20 mL h ^- 1, v _Cat = 40 mL, V̇ _{H 2} 20 NL h ^-1

LIST OF REFERENCE NUMBERS

10

reactor

11

Inlet for liquid

12

gas inlet

13

liquid distributor

14

catalyst bed

15

gas outlet

16

Outlet for liquid

17

heater

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102010025167 A1 [0002]
• WO 2011/123269 A1 [0003]
• CA 2657666 [0004]
• WO 2014/108163 A2 [0019]

Claims (18)

A process for preparing at least one hydrogenated compound from a carboxylic acid derivative comprising at least one step of reacting the carboxylic acid derivative with hydrogen in the presence of at least one catalyst, characterized by reacting an ammonium salt of a carboxylic acid in aqueous solution with hydrogen. Method according to Claim 1 , characterized in that one releases previously bound in the ammonium salt nitrogen in the form of ammonia. Method according to Claim 2 , characterized in that liberated ammonia is removed from the reaction system. Method according to Claim 2 characterized in that released ammonia is at least partially recovered and used for the re-preparation of an ammonium salt of a carboxylic acid or feeds it to another use. Method according to Claim 4 , characterized in that recovering the ammonia by washing with water or washing with acid or washing with at least part of a fermentation solution. Method according to one of Claims 1 to 5 , characterized in that as the hydrogenated compound at least one compound selected from the group comprising alcohols, aliphatic or cyclic ethers, lactones and hydroxycarboxylic acids is prepared. Method according to one of Claims 1 to 6 , characterized in that at least two different hydrogenated compounds are prepared and these are subsequently separated from one another in at least one separation step by means of at least one distillation, extraction, crystallization and / or separation via a membrane and optionally purified by further steps. Method according to one of Claims 1 to 7 , characterized in that starting from an ammonium salt of a monocarboxylic acid or a dicarboxylic acid. Method according to Claim 8 , characterized in that one starts from an ammonium salt of a carboxylic acid selected from the group comprising acetic acid, propionic acid, lactic acid, succinic acid, adipic acid, sebacic acid and oxalic acid. Method according to one of Claims 1 to 9 , characterized in that one hydrogenates an ammonium salt of a carboxylic acid obtained by fermentation, in particular a diammonium succinate. Method according to Claim 10 , characterized in that one prepares from a Diammoniumsuccinat solution by hydrogenation 1,4-butanediol and / or tetrahydrofuran and / or γ-butyrolactone. Method according to one of Claims 1 to 11 , characterized in that one uses a heterogeneous catalyst with a catalyst support selected from the group consisting of activated carbon, Al ₂ O ₃ , TiO ₂ , ZrO ₂ , SiO ₂ and MgO or mixtures thereof. Method according to one of Claims 1 to 12 , characterized in that one uses a supported catalyst with a monometallic active component, in particular comprising at least one element selected from Ru, Pd and Re. Method according to one of Claims 1 to 13 , characterized in that one uses a supported catalyst with a bimetallic active component, in particular comprising a combination of metals selected from Ru / Ir, Ru / Rh, Re / Pd, Re / Rh. Method according to one of Claims 1 to 14 , characterized in that one carries out the hydrogenation in a batch reactor, in particular a "continuous stirred tank reactor" (CSTR), being prepared by partial reduction of one of the two carboxyl groups predominantly γ-hydroxybutyric acid and γ-butyrolactone. Method according to one of Claims 1 to 14 , characterized in that one carries out the hydrogenation in a Trickle Bed reactor with feed stream and hydrogen in cocurrent or in a Trickle Bed reactor with feed stream and hydrogen in countercurrent, wherein mainly 1,4-butanediol is prepared by reduction of both carboxyl groups , Method according to one of Claims 1 to 14 , characterized in that one carries out the hydrogenation in a bubble column reactor. Method according to one of Claims 1 to 17 , characterized in that the hydrogenation is carried out at elevated temperature and / or under elevated pressure, in particular in an autoclave.