EP1699539A1

EP1699539A1 - Method for depletion of sulphur and/or compounds containing sulphur from a biochemically produced organic compound

Info

Publication number: EP1699539A1
Application number: EP04804187A
Authority: EP
Inventors: Till Gerlach; Johann-Peter Melder; Bram Willem Hoffer; Anton Meier
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 2003-12-23
Filing date: 2004-12-22
Publication date: 2006-09-13
Also published as: ZA200606041B; WO2005063354A1; JP2007515448A; IN2006CH02676A; DE10361508A1; US20070167530A1

Abstract

The invention relates to a method for the depletion of sulphur and/or a compound containing sulphur from a biochemically produced organic compound, wherein the corresponding organic compound is brought into contact with an adsorber. The invention also relates to ethanol having a given specification, which is produced according to said method or similar, and to the use thereof as solvents, disinfectants, as components in pharmaceutical or cosmetic products or in food, in cleaning agents, as an additive in a steam-reforming method for the synthesis of hydrogen or in fuel cells, or as structural components in chemical synthesis.

Description

Process for the depletion of sulfur and / or sulfur-containing compounds from a biochemically produced organic compound

description

The present invention relates to a process for the depletion of sulfur and / or sulfur-containing compounds from a biochemically produced organic compound, ethanol which can be prepared by this process and its use

There is a growing need for biochemical, e.g. fermentative, manufactured chemical compounds e.g. as building blocks in chemical synthesis for high-quality chemicals or as "green" fuels.

(See e.g. H. van Bekkum et al., Chem. For Sustainable Development 11, 2003, pages 11-21).

Examples of these renewable resources are alcohols such as ethanol, butanol and methanol, diols such as 1,3-propanediol and 1,4-butanediol, triols such as glycerol, carboxylic acids such as lactic acid, acetic acid, propionic acid, citric acid, butyric acid, formic acid, Malonic acid and succinic acid.

Instead of synthetic ethanol, which is mainly produced by hydrating ethylene, ethanol from biological sources, so-called bioethanol, can also be used for many applications.

Instead of synthetic 1,3-propanediol, which is predominantly produced by hydrolysis of acrolein to 3-hydroxypropanal under acidic catalysis followed by metal-catalyzed hydrogenation or by hydroformylation of ethylene oxide (Industrial Organic Chemistry, Weissermel and Arpe, 2003), many applications can be used 1,3-propanediol from biological sources, so-called bio-1,3-propanediol, can also be used (US Pat. No. 6,514,733, DE-A-3829 618).

Instead of synthetic lactic acid, which is produced by the hydrolysis of lactonitrile, lactic acid from biological sources can also be used for many applications (K. Weissermel and H.-J. Arpe, Industrial Organic Chemistry, Wiley-VCH, Weinheim, 2003, p. 306).

Edible oils and animal fats can be transesterified to biodiesel. In addition to biodiesel, a glycerin fraction is formed. Applications for glycerin include those in the chemical industry, for example the production of pharmaceuticals, cosmetics, polyether isocyanates, glycerol tripolyethers (K. Weissermel and H.-J. Arpe, Industrial Organic Chemistry, Wiley-VCH, Weinheim, 2003, p. 303 ). The applications for ethanol include those in the chemical industry, such as the production of ethylamines, the production of ethyl esters from carboxylic acids (esp. Ethyl acetate), the production of butadiene or ethylene, the production of ethyl acetate via acetaldehyde and the production of ethyl chloride (K. Weissermel and H.-J. Arpe, Industrial Organic Chemistry, Wiley-VCH, Weinheim, 2003), and in the cosmetic and pharmaceutical industry or in the food industry as well as in cleaning agents, solvents and paints (N. Schmitz, bioethanol in Germany, Landwirtschaftsverlag, Münster, 2003).

Further applications are: starting material in steam reforming processes and hydrogen source in fuel cells (S. Velu et al., Cat. Letters 82, 2002, pages 145-52; AN Fatsikostas et al., Cat. Today 75, 2002, pages 145 -55; F. Aupretre et al., Cat. Communication. 3, 2002, pages 263-67; V. Fierro et al., Green Chem. 5, 2003, pages 20-24; M. Wang, J. of Power Sources 112, 2002, pages 307-321).

The applications for 1,3-propanediol include those in the chemical industry, for example the production of pharmaceuticals, polyesters, polytrimethylene terephthalates, fibers.

Lactic acid is used in the food industry and in the production of biodegradable polymers.

The use of biochemically produced compounds, such as bioethanol, bio-1, 3-propanediol or lactic acid, in particular in a particularly pure form, would be more advantageous and less expensive in many of these applications.

The purification or isolation of the biochemically produced compounds is often carried out by distillation in complex, multi-stage processes.

However, as was recognized according to the invention, the advantage of the corresponding biochemically produced compound is frequently impaired by the fact that the compound contains sulfur and / or sulfur-containing compounds, in particular specific sulfur compounds, in small amounts, even after the known cleaning processes, and the sulfur or which often interferes with the sulfur-containing compounds in the respective applications.

The sulfur content of bioethanol, when used in the amination to ethylamines, has a disruptive effect by poisoning the metal catalyst. The same applies to aminations of other bio-alcohols. The alcohol amination is carried out on an industrial scale, in particular heterogeneous, hydrogenation / dehydrogenation catalysts by reacting the corresponding alcohol with ammonia, primary or secondary amines at elevated pressure and elevated temperature in the presence of hydrogen. Comp. e.g. Ullmann's Encyclopedia of Industrial Chemistry, sixth edition, 2000,, aliphatic Amines: Production from alcohols'.

The catalysts usually contain transition metals, such as Group VIII and IB metals, often copper, as catalytically active components, which are often supported on an inorganic support such as aluminum oxide, silicon dioxide, titanium dioxide, carbon, zirconium oxide, zeolites, hydrotalcites and the like, known to the person skilled in the art Materials that are applied.

If the corresponding bio-alcohol is used, the catalytically active metal surface of the heterogeneous catalysts gradually becomes more and more covered with the sulfur or sulfur compounds introduced by the bio-alcohol. This leads to an accelerated catalyst deactivation and thus to a significant impairment of the economy of the respective process.

The sulfur content of bioethanol also has a negative effect due to catalyst poisoning, e.g. in steam reforming processes for the production of hydrogen and in fuel cells (fuel cells).

In general, the sulfur content of chemicals from natural raw materials will have a negative impact on their implementation, for example as described by sulphurizing metallic centers and thereby deactivating them, or by occupying acidic or basic centers, by entering or catalyzing side reactions, by deposits in production facilities as well as through contamination of the products.

Another negative effect of sulfur and / or sulfur-containing compounds in the biochemically produced compounds is their typical unpleasant smell, which is particularly disadvantageous in cosmetic applications, in disinfectants, in foods and in pharmaceutical products.

It is therefore of great economic interest to use the sulfur and / or the sulfur-containing compounds in biochemically produced organic compounds, e.g. Bio-ethanol, bio-1, 3-propanediol, bio-1,4-butanediol, bio-1-butanol, (generally: bio-alcohols) to be depleted or practically removed entirely by a desulphurization step prior to their use.

WO-A-2003020850, US-A1-2003070966, US-A1 -2003 113598 and US-B1 -6,531,052 relate to the removal of sulfur from liquid hydrocarbons (petrol). Chemical Abstracts No. 102: 222463 (M.Kh. Annagiev et al., Doklady - Akademiya Nauk Azerbaidzhanskoi SSR, 1984, 40 (12), 53-6) describes the depletion of S compounds from technical grade ethanol (not bioethanol ) from 25-30 to 8-17 mg / l by contacting the ethanol at room temperature with zeolites of clinoptilolite and mordenite type, these zeolites having previously been conditioned at 380 ° C. for 6 h and in some Cases with metal salts, especially Fe ₂ θ3, were treated. The depleted S compounds are H ₂ S and alkylthiols (R-SH).

The object of the present invention was to provide an improved economical process for the treatment of biochemically produced organic compounds, such as bio-alcohols, e.g. Bioethanol, through which the corresponding treated compound is obtained in high yield, space-time yield and selectivity, which when used, e.g. in chemical synthesis processes, e.g. in the production of ethylamines, especially mono-, di- and triethylamine, from bioethanol and also for other uses, e.g. in the chemical, cosmetic or pharmaceutical industry or in the food industry, has improved properties. In particular, the use of a treated bioethanol should enable extended catalyst service lives in the synthesis of ethylamines.

(Space-time yields are reported in amount of product / (catalyst volume • time) "(kg / (I _cat. • h)) and / or product / (reactor volume • time)" (kg / (l _R eaktor • H)).

Accordingly, a process for the depletion of sulfur and / or a sulfur-containing compound from a biochemically produced organic compound has been found, which is characterized in that the corresponding organic compound is brought into contact with an adsorber.

Furthermore, ethanol was produced with a specific specification (see below), which can be produced by the above. Process, and its use as a solvent, disinfectant, as a component in pharmaceutical or cosmetic products or in food or in cleaning agents, as a feedstock in steam reforming processes for hydrogen synthesis or in fuel cells, or as a building block in chemical synthesis.

The method according to the invention is particularly suitable for the depletion of sulfur or a sulfur-containing compound from a compound produced by fermentation. The sulfur-containing compounds are inorganic or organic compounds, especially symmetrical or unsymmetrical C _2- ι ₀ - dialkyl sulfides, especially C ₂ -6-dialkyl sulfides, such as Diethylsulfide Di-n-propyl sulfide, di-isopropyl sulfide, very particularly dimethyl sulfide, C _2- ιo-dialkyl sulfoxides, such as dimethyl sulfoxide, diethyl sulfoxide, dipropyl sulfoxide, 3-methylthio-1-propanol and / or S-containing amino acids, such as methionine and S-methyl-methionine.

The biochemically produced organic compound is preferably an alcohol, ether or a carboxylic acid, in particular ethanol, 1,3-propanediol, 1,4-butanediol, 1-butanol, glycerin, tetrahydrofuran, lactic acid, succinic acid, malonic acid, citric acid , Acetic acid, propionic acid, 3-hydroxypropionic acid, butyric acid, formic acid or gluconic acid.

A silica gel, an activated aluminum oxide, a zeolite with hydrophilic properties, an activated carbon or a carbon membrane are preferably used as adsorbers.

Examples of silica gels that can be used are silicon dioxide, boehmite, gamma, delta, theta, kappa, chi and alpha alumina for usable aluminum oxides, and charcoals made of wood, peat, coconut shells, or also synthetic carbons are used for activated carbons Carbon blacks, made from natural gas, petroleum or derived products, or polymeric organic materials that also contain heteroatoms such as Nitrogen can be used, and for usable carbon molecular sieves, molecular sieves are made of anthracite and "hard coal" by partial oxidation, and are described, for example, in the Electronic Version of Sixth Edition of Ullmann's Encyclopedia of Industrial Chemistry, 2000, Chapter Adsorption, Paragraph, Adsorbents ,

If the adsorber is manufactured as a shaped body, for example for a fixed bed process, it can be used in any shape. Typical moldings are spheres, strands, hollow strands, star strands, tablets, grit, etc. with characteristic diameters from 0.5 to 5 mm, or also monoliths and similar structured packings (see Ullmann's Encyclopedia, Sixth Edition, 2000 Electronic Release, Chapter Fixed-Bed Reactors, Par.2: Catalyst Forms for Fixed-Bed Reactors).

In the suspension procedure, the adsorber is used in powder form. Typical particle sizes in such powders are 1 - 100 μm, but particles significantly smaller than 1 μm can also be used, for example when using soot. The filtration can be carried out discontinuously in suspension processes, for example by deep filtration. Cross-flow filtration is an option in continuous processes.

Preferred adsorbers are zeolites, in particular zeolites from the group of natural zeolites, faujasite, X zeolite, Y zeolite, A zeolite, L zeolite, ZSM 5 zeolite, ZSM 8-zeolite, ZSM 11-zeolite, ZSM 12-zeolite, mordenite, beta-zeolite, pentasil zeolite, and mixtures thereof, which contain ion-exchangeable cations.

Such, also commercial, zeolites are described in Kirk-Othmer Encyclopedia of Chemical Engineering 4th Ed. Vol 16. Wiley, NY, 1995, and also e.g. in Catalysis and Zeolites, J. Weitkamp and L. Puppe, Eds, Springer, Berlin (1999).

So-called Metal Organic Frameworks (MOFs) can also be used (e.g. Li et al., Nature, 402, 1999, pages 276-279).

The cations of the zeolite, for example H ⁺ in the case of a zeolite in the H form or Na ⁺ in the case of a zeolite in the Na form, are preferably completely or partially replaced by metal cations, in particular transition metal cations. (Loading of the zeolites with metal cations).

This can e.g. by ion exchange, impregnation or evaporation of soluble salts. However, the metals are preferably applied to the zeolite by ion exchange since, as recognized according to the invention, they then have a particularly high dispersion and thus a particularly high sulfur adsorption capacity. The cation exchange is e.g. possible starting from zeolites in the alkali metal, H or ammonium form. Such ion exchange techniques for zeolites are described in detail in Catalysis and Zeolites, J. Weitkamp and L. Puppe, Eds., Springer, Berlin (1999).

Preferred zeolites have a modulus (molar SiO ₂ : Al ₂ O ₃ ratio) in the range from 2 to 1000, particularly 2 to 100.

In the process according to the invention, adsorbers, in particular zeolites, are very particularly used which contain one or more transition metals, in elemental or cationic form, from groups VIII and IB of the periodic table, such as Fe, Co, Ni, Ru, Rh, Pd, Os , Ir, Pt, Cu, Ag and / or Au, preferably Ag and / or Cu, contain.

The adsorber preferably contains 0.1 to 75% by weight, in particular 1 to 60% by weight, particularly 2 to 50% by weight, very particularly 5 to 30% by weight (in each case based on the total mass of the adsorber ) of the metal or metals, in particular the transition metal or the transition metals.

Methods for producing such metal-containing adsorbers are known to the person skilled in the art, for example from Larsen et al., J. Chem. Phys. 98, 1994 pages 11533-11540 and J. Mol. Catalysis A, 21 (2003) pages 237-246. Ionysis techniques for zeolites are described in detail in Catalysis and Zeolites, J. Weitkamp and L. Puppe, Eds, Springer, Berlin (1999).

For example, A.J. Hemandez-Maldonado et al. in Ind. Eng. Chem. Res. 42, 2003, pages 123-29, a suitable method in which an Ag-Y zeolite is produced by ion exchange of Na-Y zeolite with an excess of silver nitrate in aqueous solution (0.2 molar) at room temperature in 24-48 hours. After the ion exchange, the solid is isolated by filtration, washed with large amounts of deionized water and dried at room temperature.

For example, T.R. Felthouse et al., J. of Catalysis 98, pages 411-33 (1986), described how the Pt-containing zeolites are produced from the H forms of Y zeolite, mordenite and ZSM-5.

The methods disclosed in WO-A2-03 / 020850 for the production of Cu-Y and Ag-Y zeolites by ion exchange starting from Na-Y zeolites are also suitable in order to obtain preferred adsorbers for the process according to the invention.

Very preferred adsorbers are: Ag-X zeolite with an Ag content of 10 to 50% by weight (based on the total mass of the adsorber) and

Cu-X zeolite with a Cu content of 10 to 50 wt .-% (based on the total mass of the adsorber).

To carry out the process according to the invention, the adsorber is generally brought into contact with the organic compound at temperatures in the range from 0 ° C. to 200 ° C., in particular from 10 ° C. to 50 ° C.

The contacting with the adsorber is preferably carried out at an absolute pressure in the range from 1 to 200 bar, in particular 1 to 5 bar.

It is particularly preferred to work at room temperature and without pressure (atmospheric pressure).

In a preferred embodiment of the process according to the invention, the corresponding organic compound is in the liquid phase, i.e. in liquid form or dissolved or suspended in a solvent or diluent, brought into contact with the adsorber.

Particularly suitable solvents are those which are able to dissolve the compounds to be purified as completely as possible or which mix completely with them and which are inert under the process conditions. Examples of suitable solvents are water, cyclic and alicyclic ethers, for example tetrahydrofuran, dioxane, methyl tert-butyl ether, dimethoxyethane, dimethoxy propane, dimethyldiethylene glycol, aliphatic alcohols such as methanol, ethanol, n- or isopropanol, n-, 2-, iso- or tert-butanol, carboxylic acid esters such as methyl acetate, ethyl acetate, propyl acetate or butyl acetate, and aliphatic ether alcohols such as methoxypropanol.

The concentration of compound to be purified in the liquid, solvent-containing phase can in principle be chosen freely and is frequently in the range from 20 to 95% by weight, based on the total weight of the solution / mixture.

A variant of the method according to the invention is that it is carried out, unpressurized or under pressure, in the presence of hydrogen.

The process can be carried out in the gas or liquid phase, fixed bed or suspension procedure, with or without backmixing, continuously or batchwise in accordance with the processes known to the person skilled in the art (for example described in Ullmann's Encyclopedia, sixth edition, 2000 electronic release, chapter “Adsorption ").

In order to obtain the highest possible degree of depletion of the sulfur compound, methods with a low degree of backmixing are particularly suitable.

The method according to the invention enables in particular the depletion of

Sulfur and / or sulfur-containing compounds from the respective compound by ≥ 90, particularly ≥ 95, very particularly ≥ 98% by weight (calculated in each case S).

The process according to the invention enables in particular the depletion of sulfur and / or sulfur-containing compounds from the respective compound to a residual content of <2, particularly <1, very particularly from 0 to <0.1 ppm by weight (calculated in each case S), e.g. determined according to Wickbold (DIN EN 41).

The bioethanol which is preferably used in the process according to the invention is generally produced from agricultural products such as molasses, cane sugar juice, corn starch or from products of wood saccharification and from sulfite waste liquors by fermentation.

Bioethanol is preferably used that was obtained by fermentation of glucose with elimination of CO ₂ (K. Weissermel and H.-J. Arpe, Industrial Organic Chemistry, Wiley-VCH, Weinheim, 2003, p. 194; Electronic Version of Sixth Edition of Ullmann's Encyclopedia of Industrial Chemistry, 2000, Chapter Ethanol, Paragraph Fermentation). The ethanol is usually obtained from the distillation process Fermentation broths won: Electronic Version of Sixth Edition of Ullmann's Encyclopedia of Industrial Chemistry, 2000, Chapter Ethanol, Paragraph Recovery and Purification.

According to the invention, the ethanol produced by the process found is used advantageously

as a building block in chemical synthesis, e.g.

in (known to those skilled in the art) processes for the preparation of a primary, secondary or tertiary ethylamine, a mono- or diethylamine, in particular mono-, di- and / or triethylamine, by reacting the ethanol with NH ₃ , a primary amine or a secondary Amine in the presence of hydrogen at elevated temperatures and pressures in the presence of a heterogeneous catalyst containing a metal of Group VIII and / or IB of the periodic table,

in processes (known to the person skilled in the art) for producing an ethyl ester, in particular by esterifying ethanol with a carboxylic acid or transesterifying a carboxylic acid ester with ethanol,

in (known to those skilled in the art) processes for the production of ethylene by dehydration,

as a solvent, disinfectant, and

as a component in pharmaceutical or cosmetic products or in food or in cleaning agents, as an ingredient in steam reforming processes for hydrogen synthesis or in fuel cells.

The present invention also relates to an ethanol which can be produced by the process according to the invention

a content of sulfur and / or sulfur-containing organic compounds in the range from 0 to 2 ppm by weight, in particular 0 to 1 ppm, very particularly 0 to 0.1 ppm (calculated in each case S), e.g. determined according to Wickbold (DIN EN 41),

a content of C _3-4 alkanols in the range from 1 to 5000 ppm by weight, particularly 5 to 3000 ppm by weight, very particularly 10 to 2000 ppm by weight,

a methanol content in the range from 1 to 5000 ppm by weight, particularly 5 to 3000 ppm by weight, very particularly 10 to 2000 ppm by weight, a content of ethyl acetate in the range from 1 to 5000 ppm by weight, particularly 5 to 3000 ppm by weight, very particularly 10 to 2000 ppm by weight, and

a content of 3-methyl-butanol-1 in the range from 1 to 5000 ppm by weight, particularly 5 to 3000 ppm by weight, very particularly 10 to 2000 ppm by weight,

having.

The content of C ₃ ^ -alkanols, methanol, ethyl acetate and 3-methyl-butanoI-1 is determined, for example, by means of gas chromatography (30 m DB-WAX column, inner diameter: 0.32 mm, film thickness: 0.25 μm, FID- Detector, temperature program: 35 ° C (5 min.), 10 ° C / min. Heating rate, 200 ° C (8 min.).

Examples

Production of Ag zeolites

Example 1: Powder Ag Zeolite

An AgNO ₃ solution (7.71 g AgNO ₃ in water, 200 ml total) was placed in a beaker, the zeolite (ZSM-5, 200 g, molar SiO ₂ / Al ₂ O ₃ ratio = 40-48, Na form) slowly added with stirring and stirred at room temperature for 2 h. Then the adsorber was filtered through a pleated filter. The adsorber was then dried in a dark drying cabinet at 120 ° C. for 16 h. The adsorber contained 2.1% by weight of Ag (based on the total mass of the adsorbers).

Example 2: Shaped Ag Ag Zeolite

An AgNO ₃ solution (22.4 g in water, 100 ml total) was placed in a beaker. The zeolite (65 g molecular sieve 13X in the form of balls with a diameter of 2.7 mm, molar SiO ₂ / Al ₂ O ₃ ratio = 2, Na form) was placed in the apparatus. 400 ml of water were then poured in and pumped at room temperature in a continuous system in a circuit. The Ag nitrate solution was added dropwise in 1 h. Now the system was pumped overnight (23 h). The adsorber was then washed free of nitrate with 12 liters of deionized water and then dried at 120 ° C. overnight in a dark drying cabinet. The adsorber contained 15.9% by weight of Ag (based on the total mass of the adsorbers). Examples A

All ppm figures in this document are based on weight.

To test the desulfurization, 10 g of the adsorber (see the following table) was heated in a drying cabinet at 150 ° C. overnight to remove adsorbed water. After the solid had cooled, it was removed from the drying cabinet and poured over with 300 ml of ethanol (absolute ethanol,> 99.8%, source: Riedel de Haen). About 17 ppm of dimethyl sulfide (corresponds to about 9 ppm of sulfur) was added to the ethanol, since preliminary tests found that dimethyl sulfide is a sulfur compound representative of the organic sulfur compounds contained in bioethanol.

The Ag / ZSM-5 adsorber was produced by ion exchange of the Na-ZSM-5 with an aqueous AgN0 ₃ solution (50 g ZSM-5, 1.94 g AgNO ₃ , 50 ml impregnation solution). A commercially available ZSM-5 (molar SiO ₂ / Al ₂ O ₃ ratio = 40-48, Na form, ALSI-PENTA®) was used. The catalyst was then dried at 120 ° C.

The Ag / SiO ₂ adsorber was produced by impregnating SiO ₂ (BET approx. 170 m ² / g, Na ₂ O content: 0.4% by weight) with an aqueous AgNO ₃ solution (40 g SiO ₂ , 1.6 g AgNO ₃ , 58 ml impregnation solution). The catalyst was then dried at 120 ° C and calcined at 500 ° C.

The Ag / Al ₂ O ₃ adsorber was produced by impregnating gamma-Al ₂ O ₃ (BET approx. 220 m ² / g) with an aqueous AgNO ₃ solution (40 g Al ₂ O _3> 1.6 g AgNO ₃ , 40 ml impregnation solution). The catalyst was then dried at 120 ° C and calcined at 500 ° C.

The ethanol / adsorber suspension was transferred to a 4-neck glass flask into which nitrogen was introduced for inerting for about 5 minutes. The flask was then closed and the suspension was stirred for 5 h at room temperature. After the experiment, the adsorber was filtered through a pleated filter. The sulfur content of the filtrate and possibly also of the adsorber was determined coulometrically:

(nb = not determined) The table shows that the silver-laden zeolite in particular was able to reduce the sulfur content to values below the detection limit (= 2 ppm).

Even after using the same Ag / ZSM-5 sample three times, <2 ppm sulfur was detected in the ethanol after the test was carried out.

Desulfurization was also found in the adsorbers, in which silver was applied to other supports such as Al ₂ O ₃ or SiO ₂ . The undoped zeolite also led to a certain sulfur depletion from the ethanol. The best result was obtained on the silver-doped zeolite.

Other materials, such as Cu / ZnO / Al ₂ O ₃ catalysts or Ni catalysts, were also suitable for S removal from bioethanol, but less well than the silver-doped zeolite, even if at elevated temperature and was worked with the addition of hydrogen.

Examples B

Example B1

To test the desulfurization, 20 g of the powdery adsorber Ag-ZSM5, 2.1% by weight of Ag were used (see Example 1) and poured over with 300 ml of ethanol (absolute ethanol,> 99.8%, source: Riedel de Haen) , Approx. 175 ppm dimethyl sulfide (> 99%, Merck) (corresponds to approx. 90 ppm sulfur) was added to the ethanol, since preliminary tests found that dimethyl sulfide is a sulfur compound representative of the organic sulfur compounds contained in bioethanol. The ethanol / adsorber suspension was transferred to a closed 4-neck glass flask. The suspension was stirred at room temperature and normal pressure. After the experiment, the adsorber was filtered through a pleated filter. The sulfur content of the entry, filtrate and possibly also of the adsorber was determined coulometrically. The same Ag-ZSM5 sample was used three more times:

Example B2

To test the desulfurization, powdered desulfurization materials were poured over with 300 ml of ethanol (absolute ethanol,> 99.8%, Riedel de Haen). About 175 ppm of dimethyl sulfide (> 99%, Merck) (corresponds to about 90 ppm of sulfur) were added to the ethanol. The ethanol / adsorber suspension was transferred to a closed 4-neck glass flask. The suspension was stirred at room temperature and normal pressure for 24 hours. After the experiment, the adsorber was filtered through a pleated filter. The sulfur content of the entry, filtrate and possibly also of the adsorber was determined coulometrically.

The materials CuO-ZnO / AI ₂ O ₃ and NiO / SiO ₂ / AI ₂ θ ₃ / Zrθ ₂ are suitable for desulfurization, but less well than, for example, a silver-doped zeolite, even if at elevated temperature and with addition was worked by hydrogen. If palladium on carbon is used, sulfur is taken up from ethanol.

Example B3

To test the adsorber, a continuous fixed bed system with a total volume of 192 ml was filled with 80.5 g of Ag-13X balls (15.9% by weight of Ag, 2.7 mm balls, described in Example 2). About 80 ppm dimethyl sulfide (> 99%, Merck) (corresponds to about 40 ppm sulfur) were added to the feed ethanol (absolute ethanol,> 99.8%, Riedel de Haen). The feed was passed over the adsorber in a swamp mode. During the sampling, the sample bottle was always cooled with an ice / salt mixture.

The sulfur determination in the entry and exit was carried out (in all examples) coulometrically (DIN 51400 part 7) with a detection limit of 2 ppm.

Example B4

To test the desulfurization, 4 g of the adsorber (see the following table) was poured over 500 ml of ethanol (absolute ethanol,> 99.8%, Riedel de Haen). About 390 ppm of dimethyl sulfide (> 99%, Merck) (corresponds to about 200 ppm of sulfur) were added to the ethanol.

The preparation of the Ag-13X is described in Example 1. CBV100 and CBV720 are Zeolite-Y systems. The doping with metals was carried out by cation exchange as in Example 1, using AgNO ₃ or CuNO ₃ solutions. The Cu-CPV720 was then calcined at 450 ° C in N ₂ .

The ethanol / adsorber suspension was transferred to a 4-neck glass flask and stirred without pressure for 24 h at room temperature. After the experiment, the adsorber was filtered through a pleated filter. The sulfur content of the filtrate and possibly also of the adsorber was determined coulometrically:

(n.b. = not determined)

The table shows that both silver-doped zeolites and copper-doped zeolites are able to desulfurize ethanol.

example

Various commercial bio-ethanol grades have been tested for their sulfur content.

Bio bio bio bio bio bio bio

EtOH 1 EtOH 2 EtOH 3 EtOH 4 EtOH 5 EtOH 6 EtOH 7 Ges.-S Öß i Öß 8 2. 49 2

(Ppm)

Sulfate-S 0.33 0.43 0.2 n.b. 0.9 6 2

(Ppm)

Ges.-S = total sulfur, determined coulometrically according to DIN 51400 Part 7 Total sulfur contents <2 ppm were determined according to Wickbold (DIN EN 41) Sulfate-S = sulfate sulfur, determined by ion chromatography according to EN ISO 10304-2

Claims

claims

1. A process for the depletion of sulfur and / or a sulfur-containing compound from a biochemically produced organic compound, characterized in that the corresponding organic compound with a

Brings adsorber into contact.

2. The method according to claim 1 for the depletion of sulfur and / or a sulfur-containing compound from a fermentatively produced compound.

3. The method according to claims 1 or 2 for the depletion of C _2-10 dialkyl sulfides, C _2-10 dialkyl sulfoxides, 3-methylthio-1-propanol and / or S-containing amino acids.

4. The method according to claims 1 or 2 for the depletion of dimethyl sulfide.

5. The method according to any one of the preceding claims, wherein the biochemically produced organic compound is an alcohol, ether or a carboxylic acid.

6. The method according to any one of claims 1 to 5, wherein the biochemically produced organic compound is ethanol, 1, 3-propanediol, 1, 4-butanediol, 1-butanol, glycerin, tetrahydrofuran, lactic acid, succinic acid, malonic acid, citric acid , Acetic acid, propionic acid, 3-hydroxypropionic acid, butyric acid, formic acid or gluconic acid.

7. The method according to any one of the preceding claims, characterized in that the adsorber is a silica gel, an aluminum oxide, a zeolite, an activated carbon or a carbon membrane.

8. The method according to the preceding claim, characterized in that the zeolite is a zeolite from the group of natural zeolites, faujasite, X zeolite, Y zeolite, A zeolite, L zeolite, ZSM 5 zeolite, ZSM 8 zeolite, ZSM 11 zeolite, ZSM 12 zeolite, mordenite, beta zeolite, pentasil zeolite, Metal Organic Frameworks (MOF) and mixtures thereof, the ion-exchangeable

Have cations.

9. The method according to any one of the two preceding claims, characterized in that the zeolite has a molar SiO ₂ / Al ₂ O ₃ ratio in the range from 2 to 100.

10. The method according to any one of the three preceding claims, characterized in that cations of the zeolite are exchanged in whole or in part for metal cations.

11. The method according to any one of the preceding claims, characterized in that the adsorber contains one or more transition metals, in elemental or cationic form, from groups VIII and / or IB of the periodic table.

12. The method according to the preceding claim, characterized in that the adsorber contains silver and / or copper.

13. The method according to any one of the three preceding claims, characterized in that the adsorber contains 0.1 to 75 wt .-% of the metal or metals.

14. The method according to any one of the preceding claims, characterized in that the bringing the biochemically produced organic compound into contact with the adsorber takes place at a temperature in the range from 10 to 200 ° C.

15. The method according to any one of the preceding claims, characterized in that bringing the biochemically produced organic compound into contact with the adsorber takes place at an absolute pressure in the range from 1 to 200 bar.

16. The method according to any one of the preceding claims for the depletion of

Sulfur and / or sulfur-containing compounds by ≥ 90 wt .-% (calculated S).

17. The method according to any one of claims 1 to 15 for the depletion of sulfur and / or sulfur-containing compounds by ≥ 95 wt .-% (calculated S).

18. The method according to any one of claims 1 to 15 for the depletion of sulfur and / or sulfur-containing compounds by ≥ 98 wt .-% (calculated S).

19. The method according to any one of the preceding claims for the depletion of

Sulfur and / or sulfur-containing compounds to <2 ppm by weight (calculated S).

20. The method according to any one of claims 1 to 18 for the depletion of sulfur and / or sulfur-containing compounds to <1 ppm by weight (calculated S).

21. The method according to any one of claims 1 to 18 for the depletion of sulfur and / or sulfur-containing compounds to <0.1 ppm by weight (calculated S).

22. The method according to any one of the preceding claims, characterized in that the method is carried out in the absence of hydrogen.

23. The method according to any one of the preceding claims, characterized in that the corresponding organic compound is brought into contact with the adsorber in the liquid phase.

24. Use of ethanol, which was obtained by a process according to any one of the preceding claims, as a solvent, disinfectant, as a component in pharmaceutical or cosmetic products or in foods or in cleaning agents, as a feedstock in steam reforming processes for hydrogen synthesis or in fuel cells , or as a building block in chemical synthesis.

25. Ethanol that can be produced by a process according to one of claims 1 to 23, characterized in that it has a sulfur and / or sulfur-containing organic compound content in the range from 0 to 2 ppm by weight (calculated S), a content of C _3rd ₄ -alkanols in the range from 1 to 5000 ppm by weight, a content of methanol in the range from 1 to 5000 ppm by weight, a content of ethyl acetate in the range from 1 to 5000 ppm by weight and a content of 3-methyl -butanol-1 in the range of 1 to 5000 ppm by weight.

26. Ethanol according to the preceding claim, characterized in that it has a content of sulfur and / or sulfur-containing organic compounds in the range from 0 to 1 ppm by weight (calculated S).

27. Ethanol according to claim 25, characterized in that it has a content of sulfur and / or sulfur-containing organic compounds in the range from 0 to 0.1 ppm by weight (calculated S).

28. Ethanol according to one of the three preceding claims, characterized in that it contains C ₃ . -Alkanols in the range of 5 to 3000 ppm by weight.

29. Ethanol according to one of the four preceding claims, characterized in that it has a methanol content in the range of 5 to 3000 ppm by weight.

30. Ethanol according to one of the five preceding claims, characterized in that it has an ethyl acetate content in the range of 5 to 3000 ppm by weight.

31. Ethanol according to one of the six preceding claims, characterized in that it has a content of 3-methyl-butanol-1 in the range of 5 to 3000 ppm by weight.