WO2017066901A1

WO2017066901A1 - Process for oxidation of alcohols

Info

Publication number: WO2017066901A1
Application number: PCT/CN2015/092157
Authority: WO
Inventors: Armin T. Liebens; Wenjuan ZHOU
Original assignee: Rhodia Operations SAS
Current assignee: Rhodia Operations SAS
Priority date: 2015-10-19
Filing date: 2015-10-19
Publication date: 2017-04-27
Anticipated expiration: 2018-04-19

Abstract

Disclosed is a process of oxidizing an alcohol of formula ROH (I), wherein R represents a saturated or unsaturated, linear, branched or cyclic C₃-C₅₀ hydrocarbon group which is optionally substituted with a heteroatom, characterized in that the oxidation is performed in a liquid phase using a peroxide as oxidant and in the presence of a base compound and a catalyst comprising at least: (i) gold metal, (ii) platinum metal and/or palladium metal, and (iii) a CeO₂, TiO₂ and/or carbon support.

Description

Process for Oxidation of Alcohols

Technical Field

This invention relates to a process for oxidation of alcohols using peroxide as oxidant and in the presence of a noble metal catalyst.

Background Art

Direct oxidation of fatty alcohols in the presence of noble metal catalyst (s) is known in the art and draws considerable interest, because this type of reaction has the potential to generate numerous fatty acid end-products with wide industrial uses, particularly in detergent and cosmetics applications.

For example, many publications described that ether carboxylic acids and/or their salts may be produced by oxidation of their corresponding ether alcohols, usually with the help of a noble metal catalyst. These publications include JP 50-96516 (KAO CORPORATION) 7/31/1975, which discloses a process for preparing carboxylic acid salts by liquid phase dehydrogenative oxidation of ether alcohols in the presence of a palladium or platinum catalyst. Disadvantageously, this process needed a high reaction temperature of 100-270℃, which can easily degrade the ether link in the desired product.

To circumvent this high temperature problem, many later-published patents for this process chose to oxidize ether alcohols using oxygen or oxygen-containing gas in the presence of a noble metal catalyst (in most cases palladium or platinum) , which generally allows a lower reaction temperature (e.g. 20-95℃) . See, for example, the description in US 3342858 (ALLIED CHEMICAL CORPORATION) 9/19/1967, US 4214101 A (KAO SOAP CO., LTD) 6/22/1980, DE 3135946 A (BAYER AG) 3/24/1983, EP 0304763 A (HENKEL KGAA) 3/1/1989, US 5292940 A (HENKEL KGAA) 3/7/1991, JP 2903187 B (KAWAKEN FINE CHEMICALS CO. LTD) 8/11/1992, US 5463114 A (HENKEL KGAA) 10/26/1995 ,US 8093414 B (CLARIANT INTERNATIONAL LTD) 2/21/2008, US 2010056735 A (CLARIANT FINANCE BVI LTD) 10/23/2008, US 20110144385 A (CLARIANT INTERNATIONAL LTD. ) 2/11/2010 ,CN 101357333 B (CHINA RESEARCH INSTITUTE OF DAILY CHEMICAL INDUSTRY) 2/4/2009, US 20120296115 A (KAO CORP) 7/14/2011, JP 2011184379 A (KAO CORP) 9/22/2011, JP 2011184380 A (KAO CORP) 9/22/2011, JP 2012149046 A (KAO CORP) 8/9/2012, JP 2012149047 A (KAO CORP) 8/9/2012, JP 2013067564 A (KAO CORP) 4/18/2013 and JP 2013151469 A (KAO CORP) 7/4/2013. However, such gas-liquid reaction has its inherent problems, such as gas diffusion limitation, insufficient mass transfer at the gas-liquid interface, and the need of additional equipment such as gas compressors. In particular, if the oxygen or oxygen-containing gas is to pass into a relatively concentrated aqueous solution of the ether alcohol reactant in the presence of the catalysts, the viscosity of the reaction mixture would increase greatly as the conversion increases, causing a significant drop of reaction rate with time, as explained in US 4214101 A. Another disadvantage of oxidation with air is that the waste gas stream entrains ether alcohol in accordance with its vapor pressure and thus causes a certain degree of environmental pollution.

As an alternative approach, EP 0018681 B (SHELL INTERNATIONALE RESEARCH) 4/17/1980 and EP 0039111 A (SHELL INTERNATIONALE RESEARCH) 4/13/1981 described an essentially liquid-phase reaction to oxidize alkoxyalkanol to its corresponding carboxylic acid, using hydrogen peroxide or t-butyl peroxide in the presence of palladium catalyst. Nevertheless, according to the examples listed in EP 0039111 A, the desirable effect of heterogeneous palladium catalyst relies on the combined use with a tert-butyl alcohol solvent, otherwise the reaction mixture solidified halfway through the reaction and the ether alcohol was only half converted. This particular solvent dependence of this process is disadvantageous, especially considering that tert-butyl alcohol is known as an instable solvent and not easy to handle in large quantity.

Recently, CN 101905158 B (CHINA RESEARCH INSTITUTE OF DAILY CHEMICAL INDUSTRY) 12/8/2010 proposed a modified liquid-phase reaction to oxidize alkoxyalkanol, using hydrogen peroxide as oxidant and a carbon-supported palladium catalyst containing at least one main group metal of Sn or Bi. While this modification on catalyst has avoided the solidification problem of the reaction mixture, the final yield of the desired ether carboxylic acid is fairly low (roughly 50％ or lower according to the Examples) .

Due to cost consideration, noble metal is always recycled when used as a catalyst. Catalysis Science & Technology 2013 (3) , 2984-2992 disclosed a study on reasons for catalyst deactivation. Said catalyst is Ceria supported gold-platinum catalysts, specially used for selective oxidation of alkyl ethoxylates. However, there are still inherent problems with gas-liquid reaction system as above mentioned.

There is thus a need to provide a better process for oxidizing alcohols, in particular fatty alcohols and the like, to obtain their corresponding carboxylic acid with a high yield while avoiding the prior art problems discussed above.

Summary of invention

The present invention relates to a process of oxidizing an alcohol of formula

ROH (I) ,

wherein R represents a saturated or unsaturated, linear, branched or cyclic C₃-C₅₀ hydrocarbon group which is optionally substituted with a heteroatom, notably for the production of its corresponding carbonyl compounds,

characterized in that the oxidation is performed in a liquid phase using a peroxide as oxidant and in the presence of a base compound and a catalyst comprising at least: (i) gold metal, (ii) platinum metal and/or palladium metal, the gold metal/ (platinum metal and/or palladium metal) molar ratio is comprised between 2: 1 and 50: 1 with the exclusion of 3: 1, 10: 1 and 20: 1, and (iii) a CeO₂, TiO₂ and/or carbon support.

As discovered by the present inventors, the special combination of peroxide oxidant, a base compound and the catalyst as above detailed can effectively facilitate the desired oxidation of an alcohol of formula (I) . Advantageously, said special combination makes it possible to perform the desired alcohol oxidation reaction in a liquid phase and thus avoids most problems encountered by gas-liquid phase operations, meanwhile providing an extremely mild, low temperature process. Furthermore, it minimizes degradation products, waste organic solvents or hardly-recyclable catalysts, and provides high conversion of the alcohol reactant and oxidant, with high selectivity and yield of the end product. Particularly, the catalyst mentioned above show excellent catalytic performance over any other noble metal catalyst applied to a support.

Economically, because of its long-term stability, the catalyst could be recycled for more times than normal noble metal without loss of catalytic activity. Notably, the process of the present invention is particularly suited to the detergent range alkoxyalkanols and fatty acid monoethanolamide.

The “alcohol” as used herein includes primary alcohols and secondary alcohols. Notably, the reaction encompassed in the "process of oxidizing an alcohol” in the present invention includes a process of obtaining carboxylic acid from a primary alcohol, a process of obtaining aldehyde from a primary alcohol, and a process of obtaining ketone from a secondary alcohol.

Throughout the description and the claims, the term "comprising one" should be understood as being synonymous with the term "comprising at least one" unless otherwise specified, and the term "between" should be understood as being inclusive of the limits. Moreover, unless otherwise indicated in the description and the claims, the values at the limits are included in the ranges of values which are given.

For the purpose of the present invention, the term "hydrocarbon group" refers to a group which contains carbon and hydrogen bonds. A hydrocarbon group may be linear, branched, or cyclic, and may contain a heteroatom such as oxygen, nitrogen, sulfur, halogen, etc.

In one preferred embodiment, the alcohol subjected to oxidation according to the process of the present invention is an ethoxylated fatty alcohol of formula (II)

R¹ (OCH₂CHR²) _nOCH₂CH₂OH (II)

wherein: R¹ represents an alkyl radical having 1 to 22 carbon atoms or a monounsaturated or polyunsaturated linear or branched alkenyl radical having 2 to 22 carbon atoms, optionally comprising at least a substituent and/or a heteroatom such as N or O； R² represents a hydrogen atom or a methyl group or a mixture thereof in the individual molecule； and n has an average number between 2 and 20.

For the purpose of the present invention, the term “alkyl” refers to saturated aliphatic groups, including linear, branched and/or cyclic groups； the term “alkyenyl” refers to unsaturated aliphatic groups having at least one double bond, including linear, branched and/or cyclic groups having at least one double bond,

R¹ in formula (II) preferably represents an alkyl group having from 3 to 22, more preferably from 8 to 20 and most preferably from 10 to 16 carbon atoms. Particular preference for R¹ is given to methyl, butyl and lauryl, of which lauryl is further preferred. The R¹ group can be an alkyl group substituted with any substituent which does not interfere with the oxidation of the hydroxyl group. For example, R¹ in formula (II) may be an alkyl group substituted with at least one substituent selected from a group consisting of ―OR³, ―CH₃, ―CH₂CH₃, -COOH, -CONH₂ and -COOR³, wherein R³ represents an alkyl or aryl group.

In formula (II) , the R² group on an individual molecule can be hydrogen, methyl or mixtures thereof. Accordingly, exemplary ethoxylated fatty alcohol of formula (II) may be selected from a group consisting of straight ethoxylates, straight propoxylates and mixed ethoxylatepropoxylate, all being detergent range ethoxylate alcohols. Commercially, detergent range ethoxylate alcohols are available with an average of 3, 7, 9 and 12 ethoxylate units per molecule. Preparation of these detergent range ethoxylate alcohols are well known in the art.

Preferably, n is an integer of from 4 to 12, more preferably from 4 to 9 in the individual molecule of formula (II) .

In particular, when the alcohol subjected to oxidation according to the process of the present invention is an ethoxylated fatty alcohol of formula (II) , the invention provides a process for producing compounds of formula (III)

R¹ (OCH₂CHR²) _nOCH₂COOB (III)

with B being a cation and R¹, R² and n having the same meaning given above, and/or of the corresponding protonated carboxylic acids by oxidizing one or more ethoxylated fatty alcohols of formula (II) ,

Preferably, the counterion B is an alkali metal cation selected from a group consisting of Li, Na, K, Rb and Cs, of which Na and K are particularly preferred.

During the oxidation reaction in the basic medium, firstly the alkali metal salts (B＝Li, Na, K, Rb, Cs) of formula (III) are formed. To produce the free ether carboxylic acids (i.e. protonated carboxylic acids of compounds of formula (III) ) , the resulting alkali metal salts of formula (III) are reacted with acids. Preferred acids are hydrochloric acid and sulphuric acid.

In another preferred embodiment, the fatty alcohol subjected to oxidation according to the process of the present invention is a fatty acid monoethanolamide of formula (IV)

wherein R’ represents a saturated, linear or branched alkyl radical having from 1 to 21 carbon atoms or a monounsaturated or polyunsaturated linear or branched alkenyl radical having from 2 to 21 carbon atoms.

In the preferred fatty acid monoethanolamides according to the process of the present invention, R’ is a saturated linear or branched alkyl radical having from 7 to 17 carbon atoms or a monounsaturated or polyunsaturated linear or branched alkenyl radical having from 7 to 17 carbon atoms, and is more preferably a saturated linear alkyl radical having from 9 to 14 carbon atoms.

As preferred examples of fatty acid monoethanolamide of formula (IV) , mentions can be made for a group consisting of lauric acid monoethanolamide, myristic acid monoethanolamide, caprylic acid monoethanolamide, capric acid monoethanolamide, palmitic acid monoethanolamide, stearic acid monoethanolamide and isostearic acid monoethanolamide, among which lauric acid monoethanolamide is particularly preferred. Here, it is also possible to use amides based on chain fractions or mixtures of these fatty acid monoethanolamides, preferably coconut fatty acid monoethanolamide.

In particular, when the alcohol subjected to oxidation according to the process of the present invention is a fatty acid monoethanolamide of formula (IV) , the invention provides a process for producing compounds of formula (V)

with B and R’ having the same meaning given above, and/or of the corresponding protonated acylglycine acids by oxidizing one or more fatty acid monoethanolamides of formula (IV) , characterized in that the oxidation is performed in a liquid phase using a peroxide as oxidant and in the presence of a base compound and a catalyst comprising at least: (i) gold metal, (ii) platinum metal and/or palladium metal, the gold metal/ (platinum metal and/or palladium metal) molar ratio is comprised between 2: 1 and 50: 1 with the exclusion of 3: 1, 10: 1 and 20: 1, and (iii) a CeO₂, TiO₂ and/or carbon support.

During the oxidation reaction in the basic medium, firstly the alkali metal salts (B＝Li, Na, K, Rb, Cs) of formula (V) are formed. To produce the free ether acylglycine acids (i.e. protonated carboxylic acids of compounds of formula (V) ) , the resulting alkali metal salts of formula (V) are reacted with acids. Preferred acids are hydrochloric acid and sulphuric acid.

Alternatively, in yet another embodiment, the alcohol subjected to oxidation according to the process of the present invention is selected from a group consisting of hexanol, octanol, 1-decanol, 1-dodecanol, 1-tetradecanol, 1-hexadecanol, 1-octadecanol, 1-octadecenol and mixtures thereof.

The base compound used in the process of the present invention may be selected from carbonates, hydroxides and oxides, and is preferably selected from hydroxides of formula BOH with B as defined above.

The peroxide used in the process of the present invention is not particularly limited, and may be selected from a group consisting of: hydroperoxides, such as hydrogen peroxide, tert-butyl hydroperoxide, and cumene hydroperoxide； diacyl peroxides, such as benzoyl peroxide, lauroyl peroxide, and the like； and ketone peroxides, such as methyl ethyl ketone peroxide, methyl isobutyl ketone peroxide, cyclohexanone peroxide, and the like. Particular preference is given to hydrogen peroxide and tert-butyl hydroperoxide, of which hydrogen peroxide is further preferred.

As hydrogen peroxide, hydrogen peroxide solution may be used. Typically, the concentration of the hydrogen peroxide solution used is 5 to 60 wt. ％, preferably 8 to 45 wt. ％ and more preferably 30 to 40 wt. ％.

The upperamount of use of peroxide in the process of the invention is not particularly limited. A typical amount of use of peroxide is 0.1 mol to 15 mol equivalent, preferably 0.5 mol to 10 mol equivalent, more preferably 2 mol to 8 mol equivalent of the alcohol reactant.

The process of the invention is preferably carried out in water.

The gold metal, platinum metal and/or palladium metal contained in catalyst used in the process of the invention are particularly pure metal.

Preferably, the gold particles used to produce the catalyst have an average particles size in the nanometer range, preferablyfrom 1 to 50 nm and more preferably from 2 to 10 nm. The platinum metal and/or palladium metal used to produce the catalyst have an average particles size in the nanometer range, preferablyfrom 0.1 to 30 nm and more preferably from 0.5 to 10 nm. The bimetallic Au-Pt and/or Au-Pd nonaparticles in the catalyst have average particles size in nanometer range, preferably from 0.1 to 15 nm. The particle size can be measured, e.g., by transmission electron microscopy or light scattering methods known in the art.

Preferably, the catalyst above mentioned is a heterogeneous catalyst.

The metal (s) of catalyst is applied to a support. Said supports are CeO₂, TiO₂ and/or carbon supports. Such supported catalyst can be produced by known methods such as adsorption, deposition-precipitation, or incipientwetness impregnation approach.

Preferably, the support particles may have a specific surface area comprises between 5 to 1300 m²/g. Preferably, surface area of CeO₂ ranges from 10 to 250 m²/g. Preferably, surface area of TiO₂ ranges from 10-1000 m²/g. Preferably, surface area of carbon ranges from 150-1200 m²/g.

The supported catalyst may comprise 0.5 to 10 wt. ％ of gold metal and platinum metal and/or palladium metal, preferably 1 to 5 wt. ％ of gold metal and platinum metal and/or palladium metal, based on the total weight of the supported catalyst.

In one embodiment, the gold metal/ (platinum metal and/or palladium metal) molar ratio is comprised between 2: 1 and 9.9: 1.

In another embodiment, the gold metal/ (platinum metal and/or palladium metal) molar ratio is comprised between 10.1: 1 and 19.9: 1.

In still another embodiment, the gold metal/ (platinum metal and/or palladium metal) molar ratio is comprised between 20.1: 1 and 50: 1.

Preferably the gold metal/ (platinum metal and/or palladium metal) molar ratio is comprised between 3.5: 1 and 9.5: 1, more preferably comprised between 4: 1 and 9: 1, particularly comprised between 4: 1 and 8: 1, specifically equal to 4, 5, 6, 7 or 8 or any possible range comprised between these values.

Preferably, at least part of the supported catalyst used in the process of the invention may be recycled. More preferably, all the supported catalyst is recycled to a fresh reaction solution.

Preferably, the recycled catalyst may be directly reused after physical separation from reaction solution.

The oxidation reaction according to the process of the invention is usually carried out at a temperature between 30℃ and 100℃, preferably between 40℃ and 90℃. The reaction pressure is generally atmospheric pressure, although higher pressure is also possible. The reaction time is generally between 1 hour and 20 hours, preferably between 5 hours and 15 hours.

The pH value in the liquid phase at the start of the oxidation reaction is preferably set between 9 and 15, more preferably between 10 and 14. Optionally, a uniform pH value is maintained throughout the reaction by adding a base in a given range.

When an alcohol is to be subjected to oxidation according to the process of the invention, the reaction can be allowed to proceed by successively adding the peroxide oxidant and the catalyst to a solution containing the alcohol and the base compound, or by successively adding the peroxide and the base compound to a mixture containing the fatty alcohol and the catalyst. Alternatively, the reaction can also be allowed to proceed conveniently by successively adding the peroxide oxidant to a mixture containing the alcohol, the base compound and the catalyst； or by mixing the peroxide, the alcohol, the base compound and the catalyst in advance to prepare a mixed reagent.

Description of embodiments

The following examples are provided to illustrate preferred embodiments of the invention and are not intended to restrict the scope thereof. Other aspects, advantages and modifications within the scope of the invention will be apparent to those skilled in the art to which the invention pertains.

Examples

Example 1

Method for Oxidizing Ethoxylated Fatty Alcohol using mixed catalyst

Gold and platinum nanoparticles were adsorbed on nanoparticulate cerium oxide using the following procedure: 350 mL aqueous solution of gold (III) chloride trihydrate (0.082 g, HAuCl₄ 3H₂O, Mw ＝393.83, Au 49.0％) and chloroplatinic acid hexahydrate (0.0103 g, H₂PtCl₆·H₂O, Mw＝518, ≥37.50％ Pt basis) in deionized water was added to 20 mL aqueous solution of 2.0 g cerium oxide in deionized water. The resulting slurry was continuously stirred vigorously for 1 hour at room temperature. To this, 5mL aqueous solution of sodium borohydride (0.13 g, Mw＝37.83, NaBH₄ 98％) in deionized water was dropwise added. The AuPt/CeO₂ solid thus produced was filtered and washed with several liters of deionized water until no traces of chlorides were detected by the AgNO₃ test, and then freeze-dried under vacuum for 24 hours. The dried AuPt/CeO₂ solid was analyzed by chemical analysis and transition electronic microscopy (TEM) , to determine the content and size of gold and platinum nanoparticles on the CeO₂ support. (Au: Pt＝8.9: 1mol ratio, 0.9wt. ％ Au and 0.1wt. ％ Pt on the CeO₂ Support)

Subsequently, 367.6 mg of the AuPt/CeO₂ solid thus produced was mixed with 355.6 mg of NaOH in 20 g of 20 wt. ％ polyoxyethylene lauryl ether (Mw＝494.7, 7EO, AEO 7 obtained from Sasol) aqueous solution, in a three necked-flask equipped with a magnetic stirrer, a cooling condenser and a pump injector, giving a NaOH/alcohol molar ratio of 1.1 and an alcohol/metal molar ratio of 432 in the mixture. The mixture was then stirred at 80℃ for 5 min. Then, 2.93 g of hydrogen peroxide solution (35 wt. ％, H₂O₂/alcohol ＝4 mol/mol) was dropwise added into the heated mixture during a period of 10 hours.

The end products in the reactor were analyzed and quantified by 1H NMR and 13C NMR, which found that 83％ of polyoxyethylene lauryl ether was converted with a 92.3％ selectivity to sodium polyoxyethylene lauryl ether carboxylate.

Example 2

Method for Oxidizing lauric acid ethanolamide using mixed catalyst

367.6 mg of the AuPt/CeO₂ solid thus produced in example 1 was mixed with 355.6 mg of NaOH in 20 g of 12.5.0 wt. ％ lauric acid ethanolamide (Mw＝243.3) and sodium dodecanoylglycinate (Mw＝ 279.2) aqueous solution, in a three necked-flask equipped with a magnetic stirrer, acooling condenser and a pump injector, giving a NaOH/alcohol molar ratio of 1.1 and an alcohol/metal molar ratio of 432 in the mixture. The mixture was then stirred at 80℃ for 5 min. Then, 2.93 g of hydrogen peroxide solution (35 wt. ％, H₂O₂/alcohol ＝6.4 mol/mol) was dropwise added into the heated mixture during a period of 10 hours. The end products in the reactor were analyzed and quantified by 1H NMR and 13C NMR, which found that 84.1 ％ of lauric acid ethanolamide was converted with a 90.7 ％ selectivity to sodium dodecanoylglycinate.

Comparative Example 1

This comparative example is performed in the same way of Example 1. The molar ratio of different catalysts to alcohol is same.

1％Au/Al₂O₃, 1％Au/TiO₂ and 1％Au/ZnO are from Stream.

5％Pt/C, 5％Ru/C, 5％Ru-Bi/C and 5％Pt-Bi/C are from Johnson Matthey.

Except 0.9％Au0.1％Pt/CeO₂, the rest catalysts are prepared as follows.

0.95％Au/CeO₂

Gold nanoparticles were adsorbed on cerium oxide (surface area: 150 m²/g, Solvay) using the following procedure: 350 mL aqueous solution of gold (III) chloride trihydrate (0.082 g, HAuCl₄ 3H₂O, Mw ＝393.83, Au 49.0％) in deionized water was added to 20 mL aqueous solution of 2.0 g cerium oxide in deionized water. The resulting slurry was continuously stirred vigorously for 1 hour at room temperature. To this, 5mL aqueous solution of sodium borohydride (0.13 g, Mw＝37.83, NaBH₄ 98％) in deionized water was dropwise added. The Au/CeO₂ solid thus produced was filtered and washed with several liters of deionized water until no traces of chlorides were detected by the AgNO₃ test, and then freeze-dried under vacuum for 24 hours. The dried Au/CeO₂ solid was analysed by chemical analysis and transition electronic microscopy (TEM) , to determine the content and size of gold nanoparticles on the CeO₂ support (Au: 0.95 wt. ％) on the CeO₂ support.

0.98％Pt/TiO₂

Platinum nanoparticles were adsorbed on titanium oxide (P25, Evonik) using the following procedure: 350 mL aqueous solution of chloroplatinic acid hexahydrate (0.1032 g, H₂PtCl₆·H₂O, Mw＝518, ≥37.50％ Pt basis) in deionized waterwas added to 20 mL aqueous solution of 2.0 g titanium oxide in deionized water. The resulting slurry was continuously stirred vigorously for 1 hour at room temperature. To this, 5mL aqueous solution of sodium borohydride (0.13 g, Mw＝37.83, NaBH₄ 98％) in deionized water was dropwise added. The Pt/TiO₂ solid thus produced was filtered and washed with several liters of deionized water until no traces of chlorides were detected by the AgNO₃ test, and then freeze-dried under vacuum for 24 hours. The dried Pt/TiO₂ solid was analyzed by chemical analysis and transition electronic microscopy (TEM) , to determine the content and size of gold and platinum nanoparticles on the TiO₂ support (Pt: 0.98 wt. ％) on the TiO₂ support.

1％Pt/CeO₂

Platinum nanoparticles were adsorbed on cerium oxide (surface area: 150 m²/g, Solvay) using the following procedure: 350 mL aqueous solution of chloroplatinic acid hexahydrate (0.1079 g, H₂PtCl₆·H₂O, Mw＝518, ≥37.50％ Pt basis) in deionized water was added to 20 mL aqueous solution of 2.0 g cerium oxide in deionized water. The resulting slurry was continuously stirred vigorously for 1 hour at room temperature. To this, 5mL aqueous solution of sodium borohydride (0.13 g, Mw＝37.83, NaBH₄ 98％) in deionized water was dropwise added. The Pt/CeO₂ solid thus produced was filtered and washed with several liters of deionized water until no traces of chlorides were detected by the AgNO₃ test, and then freeze-dried under vacuum for 24 hours. The dried Pt/CeO₂ solid was analyzed by chemical analysis and transition electronic microscopy (TEM) , to determine the content and size of platinum nanoparticles on the CeO₂ support (Pt: 1wt. ％) on the CeO₂ support.

1％Au0.1％Pd/CeO₂

Gold and palladium nanoparticles were adsorbed on cerium oxide (surface area＝150 m²/g, Solvay) using the following procedure: 350 mL aqueous solution of gold (III) chloride trihydrate (0.082 g, HAuCl₄ 3H₂O, Mw＝393.83, Au 49.0％) and palladium (II) chloride (0.0035 g, PdCl₂, Mw＝177.3, ≥60％ Pd basis) in deionized water was added to 20 mL aqueous solution of 2.0 g cerium oxide in deionized water. The resulting slurry was continuously stirred vigorously for 1 hour at room temperature. To this, 5mL aqueous solution of sodium borohydride (0.13 g, Mw＝37.83, NaBH₄ 98％) in deionized waterwas dropwise added. The AuPt/CeO₂ solid thus produced was filtered and washed with several liters of deionized water until no traces of chlorides were detected by the AgNO₃ test, and then freeze-dried under vacuum for 24 hours. The dried AuPd/CeO₂ solid was analyzed by chemical analysis and transition electronic microscopy (TEM) , to determine the content and size of gold and palladium nanoparticles on the CeO₂ support (Au: 1 wt. ％, Pd: 0.1 wt. ％, Au: Pd＝5.4: 1 mol ratio) on the CeO₂ support.

1.1％Au0.11％Pt/TiO₂ Gold

and platinum nanoparticles were adsorbed on nanoparticulate cerium oxide using the following procedure: 350 mL aqueous solution of gold (III) chloride trihydrate (0.082 g, HAuCl₄ 3H₂O, Mw ＝393.83, Au 49.0％) and chloroplatinic acid hexahydrate (0.0103 g, H₂PtCl₆·H₂O, Mw＝518, ≥37.50％Pt basis) in deionized water was added to 20 mL aqueous solution of 2.0 g titanium oxide (P25, Evonik) in deionized water. The resulting slurry was continuously stirred vigorously for 1 hour at room temperature. To this, 5mL aqueous solution of sodium borohydride (0.13 g, Mw＝37.83, NaBH₄ 98％) in deionized water was dropwise added. The AuPt/CeO₂ solid thus produced was filtered and washed with several liters of deionized water until no traces of chlorides were detected by the AgNO₃ test, and then freeze-dried under vacuum for 24 hours. The dried AuPt/TiO₂ solid was analyzed by chemical analysis and transition electronic microscopy (TEM) , to determine the content and size of gold and platinum nanoparticles on the TiO₂ support (Au: 1.1 wt. ％, Pt: 0.11 wt. ％, Au: Pt＝9.9: 1 mol ratio) on the TiO₂ support. Catalyst performance over various noble metal catalysts is reported in Table 1.

It appears catalyst of the present invention show excellent performance over other noble metal catalysts.

Table 1

Catalyst	AECA6 yield ％	TON AECA6
1％Au/Al₂O₃	81	346
1％Au/TiO₂	80	321
1％Au/ZnO	74	225
0.95％Au/CeO₂	52	249
1％Pt/CeO₂	3.0	60
5％Pt/C	14	235
0.98Pt/TiO₂	56.4	349
5％Pt-Bi/C	67.9	290
1％Au0.1％Pd/CeO₂	74.7	319
0.9％Au0.1％Pt/CeO₂	77	367
1.1％Au0.11％Pt/TiO₂	89	350
5％Ru/C	3.4	14
5％Ru-Bi/C	4.0	15

Comparative Example 2

This comparative example is performed in the same way of Example 1. The molar ratio of different catalysts to alcohol is same. This comparative example relates to catalytic recyclability test. It shows catalyst of the present invention could be recycled for more times than other noble metals without loss of catalytic activity

Table 2

Claims

A process of oxidizing an alcohol of formula

ROH (I) ,

wherein R represents a saturated or unsaturated, linear, branched or cyclic C₃-C₅₀ hydrocarbon group which is optionally substituted with a heteroatom, characterized in that the oxidation is performed in a liquid phase using a peroxide as oxidant and in the presence of a base compound and a catalyst comprising at least: (i) gold metal, (ii) platinum metal and/or palladium metal, the gold metal/ (platinum metal and/or palladium metal) molar ratio is comprised between 2: 1 and 50: 1 with the exclusion of 3: 1, 10: 1 and 20: 1, and (iii) a CeO₂, TiO₂ and/or carbon support.
The process of claim 1, wherein the gold metal/ (platinum metal and/or palladium metal) molar ratio is comprised between 2: 1 and 9.9: 1 or between 10.1: 1 and 19.9: 1 or between 20.1: 1 and 50: 1.
The process of claim 2, wherein the gold metal/ (platinum metal and/or palladium metal) molar ratio is comprised between 2: 1and 9.9: 1.
The process of claim 3, wherein the gold metal/ (platinum metal and/or palladium metal) molar ratio is comprised between 3.5: 1and 9.5: 1.
The process of claim 4, wherein the gold metal/ (platinum metal and/or palladium metal) molar ratio is comprised between 4: 1and 9: 1.
The process of claim 2, wherein the gold metal/ (platinum metal and/or palladium metal) molar ratio is comprised between 10.1: 1and 19.9: 1.
The process of claim 1, wherein the alcohol is an ethoxylated fatty alcohol of formula (II)

R¹ (OCH₂CHR²) _nOCH₂CH₂OH (II)

wherein: R¹ represents an alkyl radical having 1 to 22 carbon atoms or a monounsaturated or polyunsaturated linear or branched alkenyl radical having 2 to 22 carbon atoms, optionally comprising at least a substituent and/or a heteroatom such as N or O； R² represents a hydrogen atom or a methyl group or a mixture thereof in the individual molecule； and n has an average number between 2 and 20.
The process of claim 7, wherein R¹ is selected from an alkyl group having10-16 carbon atoms.
The process of claim 7, wherein R¹ is an alkyl group substituted with at least one substituent selected from a group consisting of―OR³, ―CH₃, ―CH₂CH₃, -COOH, -CONH₂ and-COOR³, wherein R³ represents an alkyl or aryl group.
The process of any of the claims 7-9, for producing compounds of formula (III)

R¹ (OCH₂CHR²) _nOCH₂COOB (III)

with B being a cation, and/or of the corresponding protonated carboxylic acids by oxidizing one or more ethoxylated fatty alcohols of formula (II) .
The process of claim 10, further comprising reacting the compounds of formula (III) with acids.
The process of claim 1, wherein the alcohol is a fatty acid monoethanolamide of formula (IV)

wherein R’ represents a saturated, linear or branched alkyl radical having from 1 to 21 carbon atoms or a monounsaturated or polyunsaturated linear or branched alkenyl radical having from 2 to 21 carbon atoms.
The process of claim 12, wherein the fatty acid monoethanolamide of formula (IV) is lauric acid monoethanolamide.
The process of claim 12 or 13, for producing compounds offormula (V)

with B being a cation, and/or of the corresponding protonated acylglycine acids by oxidizing one or more fatty acid monoethanolamides of formula (IV) .
The process of any one of the preceding claims, wherein the base compound is selected hydroxides of formula BOH, wherein B is an alkali metal cation selected from a group consisting of Li, Na, K, Rb and Cs.
The process of any one of the preceding claims, wherein the peroxide is selected from the group consisting of hydrogen peroxide and tert-butyl hydroperoxide.
The process of any one of the preceding claims, wherein the supported catalyst comprises 0.5 to 10 wt. ％of gold metal and platinum metal and/or palladium metal based on the total weight of the supported catalyst.
The process of claim 17, wherein the supported catalyst comprises 1 to 5 wt. ％of gold metal and platinum metal and/or palladium metal based on the total weight of the supported catalyst.
The process of any one of the preceding claims, wherein at least part of catalyst is recycled.
The use of the process of any one of the preceding claims for the production of carbonyl compounds.
The method of producing carbonyl compounds comprising the step of the process of any one of the preceding claims.