MXPA00005087A - Method for producing lactams - Google Patents

Abstract

The invention relates to a method for producing lactams by means of cyclizing hydrolysis of aminonitriles with water in the gas-phase on catalysts which contain oxides or mixed oxides of metals of groups 3, 4, 5, 13 and/or 14 of the periodic table, and optionally one additional metal oxide of groups 6, 7, 8, 9 and/or 10. In addition, the catalysts comprise a phosphate, carbonate, silicate, arsenite, arsenate, antimonite, antimonate and/or nitrate of the aforementioned metals and/or a sulfate of the aforementioned metals when metal oxides of groups 6, 7, 8, 9 or 10 are present.

Description

"PROCEDURE FOR THE PREPARATION OF LACTAMAS" DESCRIPTION OF THE INVENTION The invention relates to a process for the preparation of lactams by cyclizing hydrolysis of aminonitriles with water in the gas phase in metal oxide catalysts. Lactams are compounds of multiple applications. For example, N-methylpyrrolidone is a versatile solvent and e-caprolactam is an important monomer for idle polyacrylic fibers. The preparation of caprolactam is technically carried out by means of a Beckmann rearrangement of the cyclohexanone oxime. In this reaction, large quantities of salts, in general sodium sulfate, are formed as by-products, which must be eliminated. U.S. Patent No. 2,357,484 discloses a process for the preparation of amides and lactams from the corresponding nitriles and amines, and the aminonitriles respectively, by reaction in the gas phase with water in catalysts with dehydrating properties. Useful catalysts are, in particular, aluminum oxide, silica gel and boricorphosphoric acid.

WO 96/22974 describes a process for the preparation of lactams by cyclizing hydrolysis of aminonitriles, wherein aluminum oxide catalysts with a specific surface area of > 10 m2 / g and a volume of pores (pores with a diameter of more than 500 Á) > 10 ml / 100 g. U.S. Patent 4,628,085 discloses a process for the preparation of lactams in the gas phase, where an aromatic or aliphatic aminotril and water are contacted with a catalyst on a siliceous earth base with BET surfaces of more than 250 m2 / g and pore diameters of less than 20 nm in the presence of hydrogen and ammonia. The use of metal phosphates, especially aluminum, zirconium, niobium and lanthanum phosphates as catalysts for the preparation of lactams in the gas phase from aminonitriles and water is described in EP-A 659,741. These catalysts can also be impregnated with basic alkaline earth or alkaline metal compositions, preferably cesium, rubidium and potassium. In EP-A 748,797 a process for the preparation of lactams from dinitriles is disclosed, wherein dinitrile is hydrated to aminonitrile and aminonitrile is transformed into lactam by cyclizing hydrolysis. Catalysts for molecular hydrolysis include molecular sieves, such as acid zeolites, silicates and non-zeolitic molecular sieves, metal phosphates and metal oxides and mixed metal oxides, which are optionally amphoteric or acidic by treatment with halogens, ammonium halides or acids , such as sulfuric acid or hydrohalic acids. A disadvantage of the described processes is an insufficient selectivity of the catalysts, which on the one hand makes the isolation of the lactam more difficult and on the other hand leads to poisoning of the catalysts by the formed by-products. It is also desirable to increase the activity of the catalysts. The present invention has as an objective to prepare a process for the preparation of lactams by cyclizing hydrolysis of aminonitriles, which produces them with high selectivity and great performance in space and time and also allows a long life of the catalyst. It was surprisingly found that this objective is achieved when aminonitriles are reacted with water in metal oxides of groups 3, 4, 5, 13 and / or 14 of the periodic system as catalysts, comprising a phosphate, carbonate, silicate, arsenite , arsenate, antimony, antimonate or nitrate of the aforementioned metals and possibly a metal oxide of groups 6, 1, 8, 9 and / or 10.

The object of the present invention is therefore a process for the preparation of lactams by cyclizing hydrolysis of aminonitriles with water in the gas phase in catalysts of metal oxides, characterized in that the catalysts comprise: at least one oxide or a mixed oxide of the metals of groups 3, 4, 5, 13 and / or 14 of the periodic table, one or more oxides or mixed oxides of metals of the groups 6, 7, 8, 9 and / or 10, at least one carbonate, silicate, phosphate, arsenite, arsenate, antimony, antimonate and / or nitrate and / or in the presence of oxides or mixed oxides of the metals of groups 6 , 7, 8, 9 and / or 10, a sulphate of the aforementioned metals. The denomination of the groups of the periodic table is carried out in this specification according to the IUPAC proposal of 1985. According to the invention, the compounds of the Formula I are preferred as catalysts: MQa (ROb) cOd (I) wherein: M represents Zr, Ti, Hf, Se, Y, La, Ce, V, Nb or Ta, preferably Zr, Ti or Hf and more preferably Zr, R represents P, C, Yes, N, As or Sb, Q represents a metal of group 6, 7, 8, 9 or 10, a means a number from 0 to 10, b means a number from 0.5 to 5, c means a number of 0.001 at 0.15 and d is the magnitude required to obtain the neutrality of the load. The catalysts contain up to five water molecules per unit of formula. If a > 0.001, R may also represent S. Catalysts are more preferably used compounds of Formula I, wherein: R represents P or, if a > 0.001, can also represent S, Q represents Mn, a represents 0 to 0.1 and more preferably 0 to 0.03 and c represents 0.001 to 0.1 and more preferably 0.01 to 0.1, especially preferred are compounds in which R represents P and Q represents Mn. The catalyst materials can be used in any desired form, for example, as a powder, as chips or as other shape bodies. Co-bodies can be used, for example, extrudates or beads.

To give the form, a binder can be added, such as, for example, Aerosil, potato starch or celluloses, for example, Walocel from Wolff-Walsrode AG, these binders not being contained in the indicated Formula I. The catalyst materials can also be applied to a vehicle such as, for example, clay, silica gel, carbon, silicon carbide or silicon nitride. Preferably, the catalyst is used in the form of chíps or shape bodies in the process according to the invention. A component can be added to the catalyst bed to increase the selectivity in an amount of 0 to 70% by volume. Examples thereof are silicon dioxide, preferably quartz, silicon nitride and silicon carbide. The preparation of catalysts is carried out in a manner known per se and is known to the person skilled in the art. The catalysts according to the invention can be obtained, for example, by contacting at least one oxide and / or a hydroxide of a metal of groups 3, 4, 5, 13 and / or 14 of the periodic table one or more times with appropriate phosphates, sulfates, carbonates, silicates, arsenites, arsenates, antimonites, antimathates or nitrates and then calcined at room temperature. Suitable, for example, are the corresponding salts of metals of groups 3, 4, 5, 13 and 14 of the periodic table, the ammonium salts of the oxoacids of these metals and, if desired, the salts of the metals of groups 6 to 10 of the periodic table as well as phosphoric acid, sulfuric acid or nitric acid and their ammonium salts. The contacting is carried out, for example, by mixing an aqueous suspension of the oxide or hydroxide of metals of groups 3, 4, 5, 13 or 14 of the periodic table with a solution of the phosphates, carbonates, silicates, nitrates, arsenites , arsenates, antimonites, antimathates or desired sulfates or the corresponding free acids and then the water is removed. This procedure can be repeated. The desired components can be brought into contact at one time or in separate steps with the metal oxide suspension. Instead of the solutions of the aforementioned salts, it is also possible to use solutions of salts other than these metals in sulfuric acid, phosphoric acid or nitric acid optionally diluted with water, as long as the anion of these salts forms a volatile acid with the mineral acid . Therefore halides and acetates are also suitable salts, as long as they are used in one of the above-mentioned acids, or in aqueous solutions of these acids. The components can also be converted into a homogeneous solution, which can be obtained, for example, by evaporation or by addition of a precipitation medium, a mass of crude catalyst which is then transformed into the active form of the catalyst by dried and calcined. Another way to proceed is by spraying a body shaped metal oxide like pellets, beads, hemispheres or extrudates with aqueous solutions of suitable salts or free acids. This process can be repeated several times, drying steps generally being carried out between the different impregnation steps. In a preferred preparation process, the metals or metal oxides are contacted in a first step with one of the above-mentioned free acids and then, after a drying step, if desired, they are brought into contact with an aqueous solution. of a suitable salt of metals of groups 6 to 10 of the periodic table, in the case of manganese, for example, with Mn (N03) 2 / MnS04, MnHP0, MnC03 or MnCl2, the latter being used in sulfuric acid, nitric acid or possibly diluted phosphoric acid. It is then dried and calcined. In the preparation of catalysts based on zirconium oxide (the same applies to the other metal oxides), which are doped with P, one can proceed, for example, by suspending zirconium oxide and / or commercial zirconium hydroxide in water, in contact the -Si-suspension with diluted phosphoric acid or an aqueous solution of ammonium phosphate, removing the water, for example, by distillation under reduced pressure, and drying the residue. The crude mass of the catalyst thus obtained can be processed further and then calcined. After the drying step, another impregnation step can also be carried out with an aqueous solution of a salt of a metal of group 6 to 10, for example, a manganese salt. Calcination is commonly carried out at 500 to 900 ° C, preferably at about 700 ° C in 5 to 25 hours, preferably 10 to 20 hours. During the same it is transformed for example, HP042"or H2P04_ in P20 ~ and other cyclic phosphates and HCO3- in C032". However, this transformation, under the selected conditions, is preferably not carried out completely, so that, for example, using P, the remaining catalyst still contains P03. "The content of the individual catalysts in Zr, calculated by analysis X-ray fluorescence (R. Bock: Methoden der analytischen Chemie, Vol. 2, Nachweis- und Bestimmungsmethoden, Part 1, Verlag Chemie, Weinheim, 1980), is between 60 and 71 g, preferably between 65 and 70 g per 100 g of catalyst The content of P, S and Mn is determined by ICP (Inductively Coupled Plasma) atomic emission spectroscopy (A. Montasa, DW Golightly: Inductively Coupled Plasmas in Analytical Atomic Spectrometry, 2nd. Ed., Verlag Chemie, Weinheim). Typical values are P: 0.2 to 1 g / 100 g; S: 0.1 to 1 g / 100 g and Mn: 0.1 to 5 g / 100 g of catalyst. In the process according to the invention, aminonitriles of the Formula II are generally used: R'-HN-X-CN di: Where X means an alkylene unit with at least 2 and at most 20 atoms. In general, these are carbon atoms, but may also contain one or more, preferably however not more than three, boron, nitrogen, phosphorus, oxygen and / or sulfur atoms at any position within the alkylene unit. Between the amino group with the general formula -NR1 !! and the nitrile group contains at least 2 and preferably 3 to 6 atoms, preferably C atoms. Examples of alkylene are ethylene, 1,2- and 1,3-propylene, 1,2-, 1,3-, 1 , 4-, 2,3-butylene and 2-methyl-l, 3-propylene, 1,2-, 1,3-, 1,4-, 1,5-, 2,3-, 2,4-pentylene , 2-ethyl-l, 3-propylene, 2, 2-dimethyl-l, 3-propylene and 2- or 3-methyl-l, 4-butylene, 1,2-, 1,3-, 1,4- , 1,5- and 1,6-hexylene, 2-, 3- or 4-methyl-l, 5-pentylene, 2,2- or 2,3-dimethyl-1,4-butylene, 2- or 3- ethyl-l, 4-butylene, 2-ethyl-2-methyl-l, 3-propylene and 2-propyl-l, 3-propylene, 3-oxa- and 3-thia-l, 5-pentylene. R1 represents hydrogen or a straight or branched alkyl group with up to 20 carbon atoms. Suitable alkyl groups are, for example, methyl, ethyl, propyl, iso-propyl, n-butyl, sec-butyl, n-pentyl, n-hexyl and 2-ethylhexyl. Preferably, aminonitriles with linear alkylene units X of 3, 4, 5 or 6 carbon atoms and primary inogroups are used, ie 4-aminobutyronitrile, 5-aminovaleronitrile, e-aminocapronitrile and 7-arainoenantonitrile, more preferably e-aminocapronitrile. The ratio of water to aminonitrile can be in the range from 1 to 50 mol / mol, preferably from 1 to 15 mol / mol. The reaction can be carried out either in a bed of stirred catalyst or in a stationary one. Preferably the gas phase reaction is carried out in a fixed bed. The fixed bed can be a single bed or it can also be divided into several trays. In the latter case it is possible to influence the composition and the physical properties of the reaction mixture between the trays in positive form, for example, by adding reagents or inert gases or using for example, heat exchangers. The fixed bed can also be arranged in one or more reaction chambers, for example, in a tube bundle reactor. The reaction temperature will generally be in the range of 200 to 550 ° C, preferably 300 to 400 ° C. Too low a temperature would make evaporation of the starting material more difficult, and also under these conditions it is very difficult to obtain high conversions. At very high temperatures there is greater formation of by-products and decomposition products. During the reaction the pressure may be in the range of 0.01 to 10 bar. Preferably, the transformation is carried out at normal pressure. The reaction can also be carried out with the addition of an inert gas, for example, argon or nitrogen. The molar ratio between inert gas and aminonitrile may possibly be in the range of 0 to 100 mol / mol. In addition to the lactam, the reactor discharge generally contains unreacted aminonitrile and water, as well as ammonia or amine, and in reduced amounts by-products such as amide of aminocarbonic acid. The lactam can be obtained there in a known manner, for example, by distillation, extraction or crystallization. Typically 50 to 2000 g, preferably more than 500 g, of aminonitrile / 1 of catalyst and per hour are added to the reactor. Aminonitrile conversions are then in the range of 70 to 99.9%. The selectivity of lactam formation is generally above 85%, based on the aminonitrile used. For selected catalysts, selectivities are also achieved > 90% and especially > 93% These values are also reached after catalyst operating times of several hundred hours. The following examples are intended to clarify the process according to the invention, without limiting the scope of the invention.

E J E M P L O S Preparation of the catalysts A moist zirconium hydroxide, in the form of a coarse powder, which can be obtained commercially, was used as starting material for the preparation of the catalysts. The following catalysts were prepared: Catalyst A (according to US 2.357.484): 167 g of dry Zr (OH) 4 are combined with 5% of Walocel (Wolf f-Walsrode AG) and 67 ml of H20 in a kneader for 45 minutes and then given the Extruded form of 2 mm at a pressure of 55 bar. The extrudates are then dried for 3.5 hours at 50 to 110 ° C and calcined for 16 hours at 700 ° C and then crushed. zr: 70.5 g / 100 g Catalyst B: 55 g of dry Zr (OH) 4 are impregnated with 1.05 g of H3PO4 (85%) and 250 ml of H20, the water is removed under vacuum in the rotary evaporator and the product obtained is calcined for 16 h at 550 °. C.

Catalyst C: 55 g of dry Zr (OH) are impregnated with 3.49 g of H3P04 (85%) and 250 ml of H20. The water is removed under vacuum in the rotary evaporator and the product obtained is calcined for 16 h at 700 ° C.

Catalyst D: 50 g of dry Zr (OH) are impregnated with 1.31 g of H3P0 (85%) and 400 ml of H20. He retires. water under vacuum in the rotary evaporator and the product obtained is dried for 16 h at 180 ° C. It is impregnated with a solution of 5.1 g of Mn (N03) 2 * 4H20 in 250 ml of H20, the water is removed under vacuum in the rotary evaporator and calcined for 16 hr at 700 ° C. Zr: 66 g / 100 g P: 0.21 g / 100 g Mn: 0.68 g / 100 g Catalyst D: 50 g of dry Zr (OH) 4 are impregnated with 1.31 g of H3P04 (85%) and 400 ml of H20. The water is removed under vacuum in the rotary evaporator and the product obtained is calcined for 16 h at 180 ° C. It is impregnated with a solution of 1 g of Mn (N03) 2 * 4H20 in 250 ml of H20, the water is removed under vacuum in the rotary evaporator and calcined for 16 hr at 700 ° C. Zr: 67.5 g / 100 g P: 0.9 g / 100 g Mn: 0.7 g / 100 g Catalyst F: 162 g of dry Zr (0H) 4 are impregnated with 2.62 g of H3P04 (85%) and 400 ml of H20. The water is removed under vacuum in the rotary evaporator and the product obtained is dried for 16 h at 180 ° C. It is impregnated with a solution of 2 g of Mn (N03) 2 * 4H20 in 250 ml of H20, the water is removed under vacuum. The product thus obtained is compacted with 5% of Walocel and 46 ml of water during 30 min in the mixer and is given the form of extrudates at a pressure of 35 bar, which are dried for 3.5 hours at 110 ° C and then they are calcined for 16 hr at 700 ° C. Zr: 66.5 g / 100 g P: 0.68 g / 100 g Mn: 0.42 g / 100 g Catalyst 6: 50 g of dry Zr (OH) 4 are impregnated with 4.9 g of (NH4) 2S04 and 400 ml of H20. The water is removed under vacuum in the rotary evaporator and the product obtained is dried for 16 h at 180 ° C. It is impregnated with a solution of 5.1 g of Mn (N03) 2 * 4H20 in 250 ml of H20, the water is removed under vacuum in the rotary evaporator and calcined for 16 hr at 700 ° C. Zr: 65 g / 100 g P: 0.63 g / 100 g Mn: 3 g / 100 g Catalyst H: 50 g of dry Zr (0H) 4 are impregnated with 1.6 g of (NH4) 2S04 and 400 ml of H20. The water is removed under vacuum in the rotary evaporator and the product obtained is dried for 16 h at 180 ° C. It is impregnated with a solution of 1 g of Mn (N03) 2 * 4H20 in 250 ml of H20, the water is removed under vacuum in the rotary evaporator and calcined for 16 hr at 700 ° C.

These catalysts were tested in an electrically heated tubular reactor with an inner diameter of 30 mm, which was packed with 20 ml of catalyst as chips < 1 mm, partially 20 ml of quartz chips as aggregate. The reactor was operated with downward flow, 50 ml of quartz chips or quartz rings were placed above the catalyst as the evaporation zone. E-aminocapronitrile was added with 750 g / 1 catalyst and per hour as a 50% aqueous solution. The reaction was carried out at 360 ° C with the addition of 10 1 nitrogen / h as carrier gas at normal pressure. The yield of e-aminocapronitrile (ACN) and the selectivity for caprolactam (CPL) were determined by means of gas chromatography with internal standard and mass balance. The determinations were made after the reaction had been developed at least two days in a stable manner, with A after 165 hours, with B after 254 hours, with C after 90 hours, with D after 65 hours, with E after 95 hours, with F after 768 hours, with G after 97 hours and with H after 122 hs. For the analysis, samples were collected for at least 12 hours. The results are presented in Table 1.

TABLE 1 It is observed that by means of the impregnated catalysts of the process according to the invention, higher selectivities can be achieved with respect to the formation of caprolactams.

Claims (7)

RE IVI ND I CAC I ONE S

1. A process for lactams by hydrolysis and cyclization of aminonitriles with water in gaseous phase on metal oxide catalysts, wherein the metal oxide catalysts used are compounds of the formula I: wherein: M is Zr, Ti, Hf, Se, And, La, Ce, V, Nb or Ta, R is P, As and / or Sb, Q is a metal of group 6, 7, 8, 9 or 10, a is a number from 0 to 0.1, b is a number from 0.5 to 5, c is a number from 0.001 to 0.15, and d has the magnitude needed to achieve charge neutrality, where R can also be S, if A > 0.001.

2. The process as recited in claim 1, wherein N is Zr, Ti or Hf, in particular Zr, R is P, Q is Mn, a is? a? .1, b is 3.5 to 4 and c is 0.001 to 0.1.

3. The process as mentioned in any of the preceding claims, wherein the aminonitriles used are compounds of the formula II R1HN-X-CN wherein X is a linear or branched alkylene unit having from 2 to 20 atoms and having, where appropriate, 1, 2 or 3 boron, nitrogen, phosphorus, oxygen and / or sulfur atoms, and R1 is H or a straight or branched chain alkyl group having up to 20 carbon atoms. The process as mentioned in any of the preceding claims, wherein the ratio of the water to aminonitrile is in the range of 1 to 50 mol / mol. The process as mentioned in any of the preceding claims, wherein the temperature is in the range of 200 to 550 ° C, preferably 300 to 400 ° C. The process as mentioned in any of the preceding claims, wherein the reaction is carried out under pressures in the range of 0.01 to 10 bar. The process as mentioned in any of the preceding claims, wherein from 50 to 2000 g, preferably more than 500 g of aminonitrile are fed per liter of catalyst and hour in the reactor. RESOLUTION OF THE INVENTION Process for the preparation of lactams by cyclizing hydrolysis of aminonitriles with water in the gas phase in catalysts of metal oxides which contain: at least one oxide or a mixed oxide of the metals of groups 3, 4, 5, 13 and 14 from the periodic table, optionally one or more oxides or mixed oxides of metals of groups 6, 7, 8, 9 and / or 10, at least one phosphate, carbonate, silicate, arsenite, arsenate, anti-onylate, antimonate and / or nitrate of the aforementioned metals and / or, in the presence of oxides or mixed oxides of the metals of groups 6, 7, 8, 9 or 10, a sulphate of the aforementioned metals. Compounds of Formula I are used as metal oxide catalysts: MQa (R0b) c0d where: M represents Zr, Ti, Hf, Se, Y, La, Ce, V, Nb or Ta, R represents P, C, Si, As, Sb, and / or N, Q represents a metal of group 6, 7, 8, 9 or 10, a means a number between 0 and 10, b means a number between 0.5 and 5, c means a number between 0.001 and 0.15 and d is the quantity required to obtain the neutrality of the load, R can also represent S, when a > 0.001.