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
  • B01J21/00—Catalysts comprising the elements, oxides, or hydroxides of magnesium, boron, aluminium, carbon, silicon, titanium, zirconium, or hafnium
  • B01J21/06—Silicon, titanium, zirconium or hafnium; Oxides or hydroxides thereof
  • B01J21/063—Titanium; Oxides or hydroxides thereof
• • 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
  • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
  • B01J37/06—Washing
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D201/00—Preparation, separation, purification or stabilisation of unsubstituted lactams
  • C07D201/02—Preparation of lactams
  • C07D201/08—Preparation of lactams from carboxylic acids or derivatives thereof, e.g. hydroxy carboxylic acids, lactones or nitriles

Definitions

• the present invention relates to molding compositions which are suitable as a catalyst for the preparation of cyclic lactams by reacting aminocarbonitriles with water, comprising essentially titanium dioxide.
• shaped bodies made of titanium dioxide which are obtained by shaping titanium dioxide and calcining the shaped bodies at 300 to 800 ° C., the titanium dioxide being produced by hydrolysis of a titanium salt and before or after shaping with 0, 01 to 50 wt .-% based on titanium dioxide is treated with a mineral acid or an organic acid.
• Shaped bodies of this type have the disadvantage, however, that the titanium dioxide produced by hydrolysis has only a purity which is unsatisfactory for catalytic purposes. In reactions in which such shaped bodies are used as catalysts, this leads to losses in the yield and the selectivity.
• suitable compacts are known as catalysts which consist of up to 99% by weight of pyrogenically produced titanium dioxide with an SiO content of 0 to 1% by weight and an accessible pore volume of 45-55%. of the compact volume and a breaking strength of at least 1.630 N.
• Such compacts have the disadvantage that the use of a pressing aid, sieving the batch and converting the sifted mixture into a flowable powder must be used to produce tablets in order to produce tablets with the aid of a tablet press.
• suitable molding compositions which have no soluble constituents under the reaction conditions and contain, as an essential constituent, pyrogenic titanium dioxide, the molding compositions being obtainable by molding the pyrogenic titanium dioxide into shaped articles and treating the pyrogenic titanium dioxide before or after molding with 0, 1 to 30% by weight based on the pyrogenic titanium dioxide of an acid in which the pyrogenic titanium dioxide is sparingly soluble.
• the pyrogenic titanium dioxide can exist in various modifications such as amorphous, as anatase or as rutile or their phase mixtures.
• the above-mentioned titanium dioxide can, with compounds of the 1st to 7th, in particular 2nd, 3rd or 4th main group of the periodic table, preferably aluminum oxide, such as alpha or gamma aluminum oxide, or tin oxide, the 1st to 7th subgroup of Periodic table, the elements of the iron group or the lanthanides, preferably cerium oxide, or actinides, as well as mixtures of such compounds, or contain them.
• aluminum oxide such as alpha or gamma aluminum oxide, or tin oxide
• the 1st to 7th subgroup of Periodic table the elements of the iron group or the lanthanides, preferably cerium oxide, or actinides, as well as mixtures of such compounds, or contain them.
• these catalysts can be up to
• catalytically active oxides can be prepared in a manner known per se, for example by hydrolysis of the corresponding organyl, alcoholates, salts with organic or inorganic acids and subsequent tempering or calcining, and pyrogenically and are generally commercially available.
• the oxides are treated with an acid before or after molding.
• Organic acids such as oxalic acid, propionic acid, butyric acid, maleic acid or inorganic acids such as isopoly acids, heteropoly acids, sulfuric acid or hydrochloric acid come as the acid.
• Particularly suitable catalysts can be obtained by treatment with acetic acid, formic acid, nitric acid, in particular phosphoric acid.
• Mixtures of acids can also be used.
• the treatment can be carried out continuously or batchwise in one or more stages, the same acid, different acids or the same or different mixtures of acids being able to be used in the individual stages.
• the oxides can be treated with an acid in the manner mentioned before and after molding.
• the oxides are treated with an acid before molding.
• 0.1 to 30, preferably 0.1 to 10, in particular 0.1 to 5% by weight of acid, calculated as pure acid, based on the pyrogenic titanium dioxide, is used.
• the acid can be mixed with a liquid diluent such as water.
• the oxides can be used without additives to produce the catalysts. It is also possible, additives, such as binders, for example, titania sols, salts of the oxides used, soluble titanium salt compounds, hydrolyzable titanium compounds such as titanium alkoxides or aluminum salts such as P orentruckner, for example methyl cellulose, Kohlebstoffasern, fibers of organic polymers Add melamine, starch powder preferably before molding.
• additives such as binders, for example, titania sols, salts of the oxides used, soluble titanium salt compounds, hydrolyzable titanium compounds such as titanium alkoxides or aluminum salts such as P orenbildner, for example methyl cellulose, Kohlebstoffasern, fibers of organic polymers Add melamine, starch powder preferably before molding.
• the shaped bodies can be in various forms, for example as a ball, tablet, cylinder, hollow cylinder, pellet, granulate or strand. Shaped bodies of this type can be produced in a manner known per se using appropriate molding machines such as tableting machines, extrusion molding machines, rotary granulators, pelletizers or combinations of such machines.
• the shaped material if appropriate after an acid treatment, is advantageously dried, in particular at temperatures from 20 to 120 ° C., preferably in an inert gas atmosphere or in air and then calcined, in particular at 400-750 ° C., preferably in an inert gas atmosphere or in air
• the molding compositions can advantageously be used as a catalyst for the preparation of cyclic lactams by reacting aminocarbonitriles with water in the liquid phase in a fixed bed reactor.
• the heterogeneous catalysts can be arranged in a fixed bed.
• the reaction can be carried out in a manner known per se, for example in a trickle or preferably in a bottoms mode, in particular continuously, by bringing the reaction mixture into contact with the catalyst bed.
• the starting materials in the process mentioned are aminocarbonitriles, preferably those of the general formula I.
• n and m can each have the values 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9 and the sum of n + m is at least 3, preferably at least 4.
• R 1 and R 2 may be substituents of any kind in principle, it merely being necessary to ensure that the desired C yclmaschinesretress is not influenced by the substituents.
• R 1 and R 2 are each independently Ci-C ß alkyl or C 5 -C 7 -cycloalkyl or C 6 -C 2 aryl groups.
• Particularly preferred starting compounds are aminocarboxylic acid nitriles of the general formula
• m has a value of 3, 4, 5 or 6, in particular 5.
• the starting compound is 6-aminocaproic acid nitrile.
• the aminocarbonitriles described above can be reacted with water in the liquid phase using heterogeneous catalysts to form cyclic lactams.
• the corresponding cyclic lactams of the formula II are obtained
• the reaction can be carried out in the liquid phase at temperatures of generally 140 to 320 ° C, preferably 160 to 280 ° C; the pressure should generally be in the range from 1 to 250 bar, preferably from 5 to 150 bar, care being taken that the reaction mixture is predominantly liquid under the conditions used.
• the residence times are generally in the range from 1 to 120, preferably 1 to 90 and in particular 1 to 60 minutes. In some cases residence times of 1 to 10 minutes proved to be completely sufficient.
• At least 0.01 mol, preferably 0.1 to 20 and in particular 1 to 5 mol, of water are used per mol of aminocarbonitrile.
• the aminocarbonitrile can advantageously be in the form of a 1 to 50% by weight, in particular 5 to 50% by weight, particularly preferably 5 to 30% by weight solution in water (in which case the solvent is also the reactant) or be used in water / solvent mixtures.
• solvents are alkanols such as methanol, ethanol, n- and i-propanol, n-, i- and t-butanol and polyols such as diethylene glycol and tetraethylene glycol, hydrocarbons such as petroleum ether,
• the advantage of the process mentioned lies in the possibility of operating the cyclization continuously in a simple manner with high yields and selectivities and short residence times with very high throughputs. Since the catalysts used have a long lifespan according to previous observations, the catalyst consumption is extremely low.
• Example 1 Production of strands from pyrogenic titanium dioxide
• the product stream essentially contains ⁇ -aminocaproic acid ethyl ester and ⁇ -aminocaproic acid amide. Both can also be cyclized to caprolactam. In addition there are 5 to 8% caprolactam oligomers which can be cleaved to caprolactam.
• Catalysts 1 and 2 were produced in accordance with catalyst example 1:
• Catalyst 1 Pyrogenic titanium dioxide with 3% phosphoric acid
• Catalyst 2 Pyrogenic titanium dioxide with 0.5% formic acid extruded to 4 mm strands and then to 1.6 - 2.0 mm

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• Materials Engineering (AREA)
• Chemical Kinetics & Catalysis (AREA)
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• Polyamides (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

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• 1998
  • 1998-08-24 JP JP2000508655A patent/JP2001514076A/ja not_active Withdrawn
  • 1998-08-24 AU AU94364/98A patent/AU9436498A/en not_active Abandoned
  • 1998-08-24 KR KR1020007002192A patent/KR20010023544A/ko not_active Application Discontinuation
  • 1998-08-24 CN CN98808837A patent/CN1269787A/zh active Pending
  • 1998-08-24 BR BR9811613-4A patent/BR9811613A/pt not_active IP Right Cessation
  • 1998-08-24 CA CA002302441A patent/CA2302441A1/en not_active Abandoned
  • 1998-08-24 EP EP98947448A patent/EP1015426A1/de not_active Withdrawn
  • 1998-08-24 WO PCT/EP1998/005356 patent/WO1999011615A1/de not_active Application Discontinuation
  • 1998-08-24 US US09/486,488 patent/US6663844B1/en not_active Expired - Fee Related

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