Classifications

• • 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
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D223/00—Heterocyclic compounds containing seven-membered rings having one nitrogen atom as the only ring hetero atom
  • C07D223/02—Heterocyclic compounds containing seven-membered rings having one nitrogen atom as the only ring hetero atom not condensed with other rings
  • C07D223/06—Heterocyclic compounds containing seven-membered rings having one nitrogen atom as the only ring hetero atom not condensed with other rings with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached to ring carbon atoms
  • C07D223/08—Oxygen atoms
  • C07D223/10—Oxygen atoms attached in position 2
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P20/00—Technologies relating to chemical industry
  • Y02P20/50—Improvements relating to the production of bulk chemicals
  • Y02P20/52—Improvements relating to the production of bulk chemicals using catalysts, e.g. selective catalysts

Definitions

• the present invention relates to the preparation of lactam by cyclization of esters and amides of 6-aminocaproic acid.
• Aliphatic lactams such as in particular epsilon-caprolactam, are basic compounds for the preparation of polyamides (polyamide 6 from caprolactam).
• One of the known means of preparing these lactams consists in carrying out a cyclizing hydrolysis of the corresponding aminonitriies, more particularly of the unbranched aliphatic aminonitriies, by passage in vapor phase with water over a solid catalyst.
• US Pat. No. 2,357,484 describes a process for the preparation in the vapor phase of lactam, consisting in passing a mixture of water and aminonitrile over a catalyst, such as activated alumina, silica gel or borophosphoric acid.
• a catalyst such as activated alumina, silica gel or borophosphoric acid.
• US Patent 4,628,085 has proposed a process for the preparation of lactams in the vapor phase, comprising contacting an aliphatic or aromatic aminonitrile and water with a silica catalyst, in the form of spherical particles having a BET surface. greater than 250m 2 / g and an average pore diameter less than 20 nm, and generally in the presence of hydrogen and ammonia.
• Another possible route of access to caprolactam consists of a cyclization reaction of compounds such as 6-aminocaproic acid, esters of 6-aminocaproic acid, 6-aminocaproamide or their mixtures.
• patents WO98 / 37063 and EP 1 028109 describe a process for the cyclization of these compounds in the presence of superheated steam.
• US Patent 5,973,143 also describes the cyclization of these compounds in a liquid medium with an alcohol as solvent.
• the invention consists of a process for preparing lactam by cyclization in the vapor phase of a compound chosen from the group comprising the esters or amides of 6-aminocaproic acid or their mixtures, characterized in that the reaction is carried out in the presence of a solid catalyst.
• the reaction is carried out in the presence of water in vapor form.
• This water limits the production of by-products and promotes the recovery of caprolactam.
• the catalyst of the invention is chosen from the group comprising metal oxides such as aluminas, for example, zeolites, clays, metal phosphates.
• the clays suitable for the invention are in particular phyllosilicates which are classified by groups according to their nature and their physicochemical properties, groups among which mention may be made of kaolins, serpentines, smectites or montmorillonites, illites or micas, glauconites, chlorites or vermiculites, attapulgites or sepiolite, mixed-layer clays, allophanes or imogolites and clays with a high alumina content.
• Certain clays have a lamellar structure with an expandable network. They have the particularity of adsorbing various solvents, in particular water, between the sheets which compose them, which causes swelling of the solid as a result of the weakening of the electrostatic connections between the sheets.
• These clays essentially belong to the group of smectites (or group of montmorillonite) and for some of them to the group of vermiculites.
• Their structure is made up of “elementary” sheets with three layers: two simple layers of SiO tetrahedra in which part of the silicon can be replaced by other cations in tetrahedral position such as A
• This octahedral layer consists of a compact stack of oxygen originating either from the vertices of the preceding tetrahedra or from OH hydroxyl groups.
• the compact hexagonal network of these oxygen contains 6 octahedral cavities.
• the layer When the metal cations occupy 4 of these cavities (2 cavities out of 3 as in the case of aluminum for example), the layer is said to be dioctahedral; when they occupy all the cavities (3 cavities out of 3 as in the case of magnesium for example), the layer is said to be trioctahedral.
• the elementary sheets of these clays carry negative charges which are compensated for by the presence of exchangeable, alkaline cations such as Li + , Na + , K + , alkaline earths such as Mg 2+ , Ca 2+ , and possibly the hydronium ion H 3 0 + .
• the smectites have charge densities on the sheets lower than those of clays of the vermiculite type: approximately 0.66 charges per elementary mesh against 1 to 1.4 charges per elementary mesh for the vermiculites.
• the compensating cations are essentially sodium and calcium in smectites, magnesium and calcium in vermiculites. From the point of view of charge densities, smectites and vermiculites are intermediate between talc and pyrophyllite on the one hand, whose sheets are neutral and micas on the other hand, characterized by a high charge density on the sheets (approximately 2 per elementary mesh) generally compensated by K + ions.
• interfoliar cations of smectites and vermiculites can be fairly easily replaced by ion exchange by other cations such as, for example, ammonium ions or ions of alkaline earth metals or rare earth metals.
• the swelling properties of clays depend on various factors including the charge density and the nature of the compensating cation.
• smectites the charge density of which is lower than that of vermiculites, have swelling properties clearly superior to those of the latter, and therefore constitute a very interesting class of solids.
• the repetitive distance or basal spacing represents the shortest distance separating two crystallographically identical patterns located in two adjacent sheets.
• the basic spacing of the smectites can thus reach, by swelling, values ranging from about 1 nm to more than 2 nm.
• swelling phyllitous silicates of the smectite type
• main solids of general formula may be mentioned:
• M 2 is the metal in octahedral position
• M 3 is the metal in tetrahedral position x is the number of charges provided by the cation Mi
• the clay which constitutes the catalyst for cyclization of the esters or amides of 6-aminocaproic acid into lactam is a smectite. More preferably, the clay is montmorillonite.
• a method consisting in introducing bridges constituted by oligomers of a metal hydroxide, in particular aluminum hydroxide, has been described by LAHAV, SHAMI and SHABTAI in Clays and Clays Ore, vol.26 (n ° 2 ), p. 107-115 (1978) and in French patent 2,394,324.
• the formation of bridges consisting of oligomers of mixed hydroxides of silicon and boron is described in US Pat. No. 4,248,739.
• a technique for bridging smectites, by dialysis, using aluminum hydroxides, chromium, zirconium and titanium, etc. is claimed in patent EP 0.073.7 8.
• These methods consist in principle of bringing the clay into contact with a solution containing more or less oligomerized ionic species of the hydroxyaluminic type (in the case of aluminum). This operation is generally carried out in a slightly concentrated solution, at a temperature below 80 ° C. and if possible in the absence of cloudiness consisting of the start of precipitation of the metal hydroxide.
• concentrations of metal ion and clay must be optimized so that sufficient solid pillars are formed and the porosity of the clay is not greatly reduced by the insertion of too much metal oxide.
• the bridged smectites acquire a strong acidity although globally lower than those of conventional zeolites of type Y or mordenite for example.
• the clay used as a catalyst for cyclization of esters or amides of 6-aminocaproic acid into lactam is bridged.
• the catalyst can comprise, in addition to a clay, one or more other metallic compounds, often called dopants, such as for example chromium, titanium, molybdenum, tungsten, iron compounds, zinc.
• dopants such as for example chromium, titanium, molybdenum, tungsten, iron compounds, zinc.
• these dopants usually represent, by weight per weight of clay, from 0% to 10% and preferably from 0% to 5%.
• metal compound means both the metal element and the metal ion or any combination comprising the metal element.
• Another preferred catalyst class of the invention consists of a particulate catalyst obtained by shaping at least one simple or mixed mineral oxide of at least one element chosen from the group consisting of silicon, aluminum, titanium, zirconium, vanadium, niobium, tantalum, tungsten, molybdenum, iron, rare earths.
• the particulate catalyst comprises at least one macroporosity characterized by a pore volume corresponding to the pores with a diameter greater than 500 ⁇ , greater than or equal to 5 ml / 100 g.
• This macroporosity is advantageously formed during the process of forming the particles by techniques described below or as, for example, the addition of porogen.
• the catalyst can be used in various forms such as balls, crushed, extruded in the form of hollow or solid cylindrical granules, honeycomb, pellets, the shaping possibly being possible using a binder. .
• beads of mineral oxides resulting from shaping by oil-drop can for example be prepared by a process similar to that described for the formation of alumina beads in patents EP-A-0 015 801 or EP-A-0 097 539.
• the control of the porosity can be produced in particular, according to the process described in patent EP-A-0 097539, by coagulation in drops of a suspension, of an aqueous dispersion of mineral oxide.
• the balls can also be obtained by the agglomeration process in a bezel or rotating drum.
• the porosity of these extrudates can be controlled by the choice of the oxide used and by the conditions of preparation of this oxide or by the conditions of kneading of this oxide before extrusion.
• the mineral oxide can thus be mixed during mixing with porogens.
• the extrudates can be prepared by the process described in US Pat. No. 3,856,708.
• the catalyst particles have a specific surface greater than 10 m 2 / g and a pore volume equal to or greater than 10 ml / 100 g, the pore volume corresponding to pores with a diameter greater than 500 ⁇ being greater than or equal to 10 ml / 100 g.
• the catalyst particles have a specific surface greater than 50 m 2 / g.
• they have a total pore volume greater than or equal to 15 ml / 100 g with a pore volume corresponding to the pores with a diameter greater than 200 ⁇ , greater than or equal to 15 ml / 100 g, preferably greater than or equal to 20 ml / 100 g.
• These particulate catalysts can also comprise at least one element chosen from the list consisting of silicon, titanium, zirconium, vanadium, niobium, tantalum, tungsten, molybdenum, iron, rare earths or by deposition and / or adsorption of at least one oxygen-containing compound of at least one element chosen from the group consisting of elements belonging to groups 1 to 16 of the universal classification of elements (new classification), this list also including rare earths. These elements or compounds are deposited or adsorbed on the particulate catalyst.
• these elements are advantageously chosen from the list comprising silicon, titanium, zirconium, vanadium, niobium, tantalum, tungsten, molybdenum, phosphorus, boron, iron, alkalis, alkaline earths, rare earths.
• the oxygenated compound is advantageously a simple or mixed oxide of one or more of the elements mentioned above.
• the porous catalyst is preferably an aluminum oxide.
• this alumina has the characteristics of specific surface and distribution of pores defined above.
• the concentration by weight of oxygenated compound supported on a porous support is advantageously between 1000 ppm and 30% expressed in mass of element of the oxygenated compound relative to the total mass of the catalyst. This concentration is more preferably between 0.5% and 15% by weight.
• the porous supports correspond to aluminas in accordance with the invention, these are generally obtained by dehydration of gibbsite, bayerite, nordstandite or of their various mixtures. The different processes for preparing aluminas are described in the KIRK-OTHMER encyclopedia, volume 2, pages 291 - 297.
• the aluminas used in the present process can be prepared by contacting a hydrated alumina, in finely form divided, with a stream of hot gas at a temperature between 400 ° C and 1000 ° C, then maintaining contact between the hydrate and the gases for a period ranging from a fraction of a second to 10 seconds and finally separation of the partially dehydrated alumina and the hot gases.
• a stream of hot gas at a temperature between 400 ° C and 1000 ° C
• alumina agglomerates obtained previously in an aqueous medium, optionally in the presence of acid, at a temperature above 100 ° C. and preferably between 150 ° C. and 250 ° C., for preferably between 1 and 20 hours, then drying and calcining.
• the calcination temperature is adjusted so as to obtain specific surfaces and pore volumes located in the zones of values indicated above.
• the catalysts of the invention advantageously have a specific surface greater than 50 m 2 / g.
• they advantageously have pores with a diameter greater than 0.1 ⁇ m, the pore volume provided by these pores being greater than or equal to 5 ml / 100 g, advantageously greater than or equal to 10 ml / 100 g.
• these catalysts also comprise pores with a diameter equal to or greater than 0.5 ⁇ m, the corresponding pore volume being equal to or greater than 5 ml / 100 g, preferably greater than or equal to 10 ml / 100 g.
• This pore volume generated by the pores with a diameter greater than 500 ⁇ , preferably greater than 0.1 ⁇ m and advantageously greater than 0.5 ⁇ m makes it possible to obtain catalysts with a long cycle time as a catalyst for the cyclization reaction.
• esters or amides of 6-aminocaproic acid in lactams can be used in industrial processes for the production of lactams.
• the catalysts comprising oxygenated compounds supported by a porous catalyst are obtained, generally by impregnation of the catalyst, in particular of alumina, by a solution of a salt or compounds of the elements mentioned above, then dried and calcined at a temperature equal to or greater than 400 ° C, to optionally and advantageously transform said compounds or salts into oxygenated compounds, preferably into oxides.
• the oxides are deposited on the surface of the pores of the porous catalyst.
• the element compounds can be added to the material constituting the porous catalyst before it is formed or during the forming process.
• the calcination of the impregnated catalysts is preferably carried out under an oxidizing atmosphere such as air.
• the catalyst can be a metal phosphate of general formula:
• M O
• - Imp represents a basic impregnation compound consisting of an alkali or alkaline-earth metal, or mixtures of several of these metals, associated with a counter anion to ensure electrical neutrality, - n represents 1, 2 or 3,
• - p represents a number between 0 and 1/3 and corresponds to a molar ratio between the impregnating Imp and the impregnated ( ⁇ 4) n H ⁇ M.
• metals of groups 2a, 3b, 4b, 5b, 6b, 7b, 8, 2b, 3a, 4a and 5a of the periodic table of the elements there may be mentioned in particular beryllium, magnesium, calcium, strontium, barium, aluminum, boron, gallium, Pindium, yttrium, lanthanides such as lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium, zirconium, titanium, vanadium, niobium, iron, germanium, tin, bismuth.
• beryllium magnesium, calcium, strontium, barium, aluminum, boron, gallium, Pindium, yttrium, lanthanides such as lanthanum, cerium, praseodymium, neodymium,
• lanthanide phosphates a first family can be distinguished which groups the light rare earth orphophosphates, also called ceric rare earths, including lanthanum, cerium, praseodymium, neodymium, samarium and europium. These orthophosphates are dimorphic. They have a hexagonal structure and evolve towards a monoclinic structure, when they are heated to a temperature of 600 to 800 ° C.
• a second family of lanthanide phosphates groups the gadolinium, terbium and dysprosium orthophosphates. These orthophosphates have the same structure as the ceric rare earth orthophosphates, but also have a third crystalline phase of quadratic structure at high temperature (around 1700 ° C).
• a third family of lanthanide phosphates includes the orthophosphates of heavy rare earths, also called yttric rare earths, including yttrium, holmium, erbium, thulium, ytterbium and lutetium. These compounds crystallize only in the quadratic form.
• ceric rare earth orthophosphates preferential use is made of ceric rare earth orthophosphates. It is possible to use metal phosphates of the preceding formula which are mixtures of phosphates from several of the metals indicated above or mixed phosphates from several of the metals indicated above or alternatively mixed phosphates containing one or more of the metals indicated above and one or more other metals such as alkali or alkaline earth metals.
• the counter anions entering the formula of the impregnation compound Imp are basic. It is possible in particular to use the hydroxide, phosphate, hydrogen phosphate, dihydrogen phosphate, chloride, fluoride, nitrate, benzoate, oxalate ions, without these citations being limiting.
• the molar ratio p is preferably between 0.02 and 0.2. If we refer to the general techniques for the preparation of phosphates (as described in particular in "PASCAL P. New treaty of mineral chemistry” volume X (1956), pages 821-823 and in "GMELINS Handbuch der anorganischen Chemie” (8 th edition) volume 16 (C), pages 202-206 (1965), we can distinguish two main routes of access to phosphates: On the one hand, the precipitation of a soluble salt of the metal (chloride, nitrate) by l ammonium hydrogen phosphate or phosphoric acid, on the other hand, dissolving the metal oxide or carbonate (insoluble) with phosphoric acid, usually hot, followed by precipitation.
• the precipitated phosphates obtained according to one of the indicated routes can be dried, treated with an organic base (such as ammonia) or mineral (such as an alkali metal hydroxide) and be subjected to calcination, these three operations being able to be performed in the order indicated or in a different order.
• an organic base such as ammonia
• mineral such as an alkali metal hydroxide
• the metal phosphates of the preceding formula for which the symbol p is greater than 0, can be prepared by impregnating the compound (P ⁇ 4) n H n M prepared according to one of the techniques described above, with a solution or a suspension of Imp in a volatile solvent, such as water preferably.
• an advantageous process for the preparation of these phosphates consists of: a) carrying out the synthesis of the compound (P04) n H ⁇ M; then preferably without separating (P ⁇ 4) n H ⁇ M from the reaction medium; b) introducing the impregnating agent Imp into the reaction medium; c) separating any residual liquid from the reaction solid; d) dry and possibly calcine.
• the performance of these catalysts and in particular their resistance to deactivation can be further improved by calcination.
• the calcination temperature will advantageously be between 300 ° C and 1000 ° C and preferably between 400 ° C and 900 ° C.
• the duration of the calcination can vary within wide limits. As an indication, it is generally between 1 hour and 24 hours.
• lanthanum phosphate calcined lanthanum phosphate, lanthanum phosphate associated with a derivative of cesium, rubidium or potassium
• cerium phosphate cerium phosphate associated with a cesium, rubidium or potassium compound
• aluminum phosphate phosphate aluminum associated with a cesium, rubidium or potassium compound
• calcined niobium phosphate, niobium phosphate associated with a cesium, rubidium or potassium compound calcined zirconium hydrogen phosphate, associated zirconium hydrogen phosphate to a compound of cesium, rubidium or potassium.
• the cyclization reaction preferably requires the presence of water to limit the formation of by-products.
• the molar ratio between water and the compound to be cyclized is usually between 0.5 and 50 and preferably between 1 and 20.
• the compound to be cyclized and the water can be used in the form of their mixtures in the vapor state or can be introduced separately into the reactor.
• Any inert gas can be used without disadvantage as a carrier, such as nitrogen, helium or argon.
• the temperature at which the process of the invention is implemented must be sufficient for the reactants to be in the vapor state. It is generally between 200 ° C and 450 ° C and preferably between 250 ° C and 400 ° C.
• the contact time between the compound to be cyclized and the catalyst is not critical. It can vary depending on the apparatus used in particular. This contact time is preferably between 0.5 to 200 seconds and even more preferably between 1 and 100 seconds.
• Pressure is not a critical process parameter. Thus, it is possible to operate under pressures from 10 "3 bar to 200 bar. Preferably, the process will be carried out under a pressure of 0.1 to 20 bar.
• an inert solvent under the reaction conditions such as for example an alkane, a cycloalkane, an aromatic hydrocarbon or one of these. previous hydrocarbons in halogenated form, and thus to have a liquid phase in the reaction flow.
• a medium comprising methyl aminocaproate in solution in water or methanol is introduced using a syringe pump at a flow rate of 4.3 L / h in a pyrex tube placed vertically in an oven whose temperature is 300 ° C and swept by a nitrogen current of 5.3 L / h.
• 2g of catalyst (macroporous alumina sold by the company PROCATALYSE under the name SCM 139 XL are placed between 2 layers of glass powder of volume 5 ml. The injection is made just above the upper glass layer, the current of nitrogen carries the products through the catalyst bed, leaving the oven, the gases are condensed in a tube placed in an ice bath and then analyzed by gas chromatography.
• Example 1 the medium contains 60% by weight of aminocaproate methyl the conversation of methyl aminocaproate is total, the selectivity for caprolactam is 26%
• Example 2 the medium contains 40% by weight of methyl aminocaproate the conversation for methyl aminocaproate is total, the selectivity for caprolactam is 68%.

Landscapes

• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Catalysts (AREA)

Applications Claiming Priority (3)

Publications (1)

Family

ID=8870837

Family Applications (1)

Country Status (7)

Families Citing this family (1)

Family Cites Families (5)

• 2001
  • 2001-12-21 FR FR0116659A patent/FR2833946B1/fr not_active Expired - Fee Related
• 2002
  • 2002-12-13 EP EP02799811A patent/EP1456177A1/fr not_active Withdrawn
  • 2002-12-13 CN CN2010102978788A patent/CN102050773A/zh active Pending
  • 2002-12-13 RU RU2004122428/04A patent/RU2275358C2/ru not_active IP Right Cessation
  • 2002-12-13 CN CNA028271734A patent/CN1615298A/zh active Pending
  • 2002-12-13 WO PCT/FR2002/004344 patent/WO2003053935A1/fr not_active Application Discontinuation
  • 2002-12-13 AU AU2002364448A patent/AU2002364448A1/en not_active Abandoned
  • 2002-12-20 TW TW091136805A patent/TWI332498B/zh not_active IP Right Cessation

Non-Patent Citations (2)

Also Published As

Similar Documents

Legal Events