Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
  • B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
  • B01J23/76—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
  • B01J23/84—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36 with arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
  • B01J23/85—Chromium, molybdenum or tungsten
  • B01J23/86—Chromium
  • B01J23/868—Chromium copper and chromium
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C209/00—Preparation of compounds containing amino groups bound to a carbon skeleton
  • C07C209/44—Preparation of compounds containing amino groups bound to a carbon skeleton by reduction of carboxylic acids or esters thereof in presence of ammonia or amines, or by reduction of nitriles, carboxylic acid amides, imines or imino-ethers
  • C07C209/50—Preparation of compounds containing amino groups bound to a carbon skeleton by reduction of carboxylic acids or esters thereof in presence of ammonia or amines, or by reduction of nitriles, carboxylic acid amides, imines or imino-ethers by reduction of carboxylic acid amides

Definitions

• the present invention relates to an improved process for obtaining long chain N, N-dimethyl-N-alkylamines by catalytic hydrogenation of the corresponding dimethylamides. It is a question of obtaining by this route N, N-dimethyl-N-alkylamines free of heavy alcohols intended, inter alia, for the manufacture of quaternary ammonium salts for detergency or of industrial bactericides or disinfectants.
• N, N-dimethyl-N-alkylamines by reaction of dimethylamine on an alkyl halide, on a fatty alcohol or on an alpha-olefin. These are industrial routes, but which use expensive raw materials.
• a more economical way consists in reacting dimethylamine with a fatty acid to form N, N-dimethyl-alkylamide, then in hydrogenating the fatty N, N-dimethylalkylamide in N, N-dimethyl-N-alkylamine.
• Several industrial embodiments are known thereof, which operate by catalytic hydrogenation under hydrogen pressure; for example :
• the present invention resides in a process for obtaining N, N-dimethyl-N-alkylamines of general formula
• R is an alkyl or alkenyl residue comprising from 12 to 24 carbon atoms, and preferably amines with a C12-C14 alkyl chain, containing less than 1% of fatty alcohols, by catalytic hydrogenation of the corresponding N, N-dimethylalkylamides , using catalysts of the copper chromite type, under a stream of circulating hydrogen, at pressures between 10 and 100 bars, and at temperatures between 220 and 280 ° C., the catalyst typically containing, in addition to copper oxide and copper chromite, manganese oxide.
• doped copper chromite catalyst is understood to mean compositions essentially based on copper and chromium oxides, containing a few percent of an oxide of another metal, such as barium, magnesium or calcium, the role of which is stabilize the catalyst by delaying the reduction of copper when the catalyst operates in hydrogenation, with a certain loss of activity and selectivity.
• Barium doped copper chromite catalysts are used to catalyze the hydrogenation of aldehydes to alcohols. It was not known that copper chromites doped with manganese are advantageous in the hydrogenation of amides into amino acids practically free from alcohols. It is this unexpected behavior of such a catalyst that one takes advantage of the invention to produce the N, N-dimethyl-N-alkylamines of desired quality.
• the thermal decomposition product, or the co-precipitate, once washed and dried in an oven, is calcined in air at a temperature above 350oC and not exceeding 600 ° C, and preferably at a temperature of the order of 450oC, then preferably reduced by hydrogen, at a temperature between 100 and 300oC.
• the catalytic compositions according to the invention contain from 10 to 75% by weight of copper oxide CuO, from 10 to 75% of chromium oxide Cr203 and from 2 to 20% of manganese oxide MnO2. Preferred were compositions of 45 to 49% CuO, 46 49% Cr203 and 2-10% MnO2.
• the catalyst is most often in black powdery form; it can be presented in tablets or extruded granules. Some of these compositions are also commercial.
• Reactors are used equipped with a turbine and stirring blades, constructed so as to be able to operate at a pressure of the order of 100 bars, which is loaded with N, N-dimethylalkylamide and 0.5 at 20% by weight of the catalyst, the amounts of approximately 5% being those which will be used in practice.
• the circulation of pressurized hydrogen is used for this; the water is condensed and the hydrogen is recycled using a booster.
• the reaction is carried out at temperatures between 180 and 300 ° C, and preferably between 220 and 280 ° C, and under a total pressure between 10 and 100 bars.
• the reaction proceeds more quickly under high pressure, but to the detriment of selectivity, in particular due to a greater contribution of the production of alcohols according to the reaction.
• the flow of circulating hydrogen is between 0.2 liters of H2 / g of amide / hour and 2 liters of H2 / g of amide / hour (i.e. very substantially between 0.2 mole H2 / mole amide / hour and 2 moles H2 / mole amide / hour).
• the choice of significantly higher flow rates is not followed by any improvement in the activity or in the selectivity of the catalyst.
• the choice of the catalyst doped with manganese and of the operating conditions indicated lead to a low level of alcohols in the reaction products, it is necessary to transform into amines the alcohols which could nevertheless have formed. What is achieved by adding dimethylamine, thanks to the reaction
• the proportion of dimethylamine generally does not exceed 1 mol% (22.5% by weight) of the circulating hydrogen. It is advantageous to introduce dimethylamine only towards the end of the reaction, when the alkalinity has reached approximately 75% of the theoretical alkalinity.
• N, N-dimethyl-N-saturated alkylamines other than the alkyl- (C12-C14) -amines in particular to the N, N-dimethyl-N-alkylamines which have their origin in fatty acids of animal or vegetable origin, for example tallow fatty acids (on average C16-C18), soybeans (on average C16-C18 unsaturated) or rapeseed (on average C18-C22), and is transposed to obtaining homologs such as N, N-diethyl-N-alkylamines from N, N-diethylalkylamides. Its adaptation to a continuous process for the production of N, N-dimethyl-N-alkylamines is also within the reach of the skilled person.
• a Cu-Cr-Mn mass catalyst is prepared by mixing in 500 ml of distilled water 89 grams of Cu (NO3) 2, 6H2O, 240 grams of Cr (NO3) 3, 9 H2O and 10 grams of Mn (NO3), 4H2O.
• the hydroxides are precipitated with stirring by adding a 2 M solution of Na2CO3 (212 grams for 1 liter of water) to a pH of 6.5.
• the precipitate is filtered, washed abundantly with distilled water and the paste obtained is dried at 150 ° C. in an oven for 16 hours. After drying, the solid is ground into a fine powder (2 to 10 ⁇ m) and again calcined in air in an oven at a temperature of 450 ° C.
• the initially green powder turns black.
• This product is very partially crystallized.
• the X-ray diffraction diagram was given on plate 1/1, on which the characteristic peaks of the chromite CuCr204 are distinguished, and those of the copper oxide CuO.
• Manganese oxide peaks are absent, which testifies to the presence of manganese oxide in the amorphous phase.
• the catalyst of Example 1 is used in the hydrogenation of N, N-dimethylated amides of carbon chain length essentially C12-C14 (0.15% of C8, 0.2% of C10, 66% of C12, 33% of C14).
• N, N-dimethylalkylamides are obtained industrially by direct amidation of the corresponding fatty acids with dimethylamine, for example by maintaining the fatty acid at 170-190 "C for 10 to 16 hours under circulation of dimethylamine at 0.2- 2 bars, then removing under vacuum the excess of dimethylamine trapped in the N, N-dimethyl-alkylamide formed.
• the dimethylamide used has an amide alkalinity equal to 4.2 mol / kg and contains 0 , 44% residual C12-C14 fatty acid and 0.02% water.
• the temperature is increased to 235 ° C at a rate of 5 ° C / min and the pure hydrogen is then replaced by a H2-dimethylamine mixture containing 0.8% dimethylamine in 400 l / h of H2.
• Samples are taken so as to follow the kinetics of the reaction by measuring the amide alkalinity or by chromatographic analysis.
• the reaction is stopped by cutting the temperature supply and stirring, and reducing the pressure to atmospheric pressure, a quarter of an hour after obtaining zero amide alkalinity.
• the catalyst then settles hot in the N, N-dimethyl- (C12-C14) amine formed, and the latter is withdrawn by suction, after decompression of the autoclave through an orifice located on the cap of the reactor; the catalytic paste remains at the bottom of the reactor.
• the reactor is recharged with 400 grams of amide and 4 grams of Cu-Cr-Mn catalyst (in particular to compensate for the losses due to the taking of samples). The results obtained in the first operation on new catalyst, and in the following five operations on recycled catalyst, are reported in Table 1.
• the main reaction by-product is dialkylmethylamine, which can be easily separated from alkyldimethylamine by distillation. Esters with a fatty chain are also obtained in a proportion of less than 1%.
• the average yield of alkyldimethylamine is 87.3% by weight.
• Example 2 the same operating conditions were applied as in Example 2, in particular by practicing the same type of recycling, but with a Cu-Cr-Ba catalyst containing 40% of CuO, 45.5% of Cr203 and 9 , 5% BaO, with a specific surface of 36 m2 / g.
• This catalyst was prepared as in the example, unlike the use of Ba (NO3) 2, H2O instead of Mn (NO3), 4H2O.
• the tenth operation delivered 84 kg of raw amines and 8 kg of recyclable fat training.
• Example 5 The procedure was as in Example 5, with the difference that dimethylamine is introduced as soon as the operating temperature (235 ° C.) has been reached, at a time when the alkalinity developed is still very low.
• the crude amine obtained in the first cycle now only titers 90% of tertiary amines of the dimethyl- (C12-C14) amine type, which demonstrates the advantage of the practice, according to the invention, of not introducing dimethylamine. only when the alkalinity is established at approximately 75% of the theoretical value.

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• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)
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• 1988
  • 1988-07-08 FR FR8809280A patent/FR2633927B1/fr not_active Expired - Lifetime
• 1989
  • 1989-07-05 EP EP89908212A patent/EP0377732A1/fr active Pending
  • 1989-07-05 US US07/460,962 patent/US5075505A/en not_active Expired - Fee Related
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  • 1989-07-05 WO PCT/FR1989/000352 patent/WO1990000539A1/fr not_active Application Discontinuation
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• 1990
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