The method of producing lactam

 

(57) Abstract:

The lactams produced by interactions in the vapor phase of aliphatic aminonitriles with water in the presence of a solid catalyst which is a metal phosphate of General formula (PO4)nHhM, (Imp)pwhere M is a divalent, trivalent, tetravalent or pentavalent element selected in the groups 2A, 3b, 4B, 5B, 6b, 7b, 8, 2B, 3A, 4A, and 5A of the Periodic system of elements or a mixture of several of these elements, or M=O, Impthat is the main impregnating compound consisting of alkali or alkaline earth metal or of a mixture of several of these metals are associated with a counterion to provide electrical neutrality, n=1, 2, or 3, h=0,1 or 2, p is a number between 0 and 1/3, and corresponds to the molar ratio between the impregnating agent Impand impregnated (PO4)nHhM. Application of these catalysts increases the selectivity of the reaction, increases the removal of the final product and increased mainegenealogy mileage and service life of the catalyst. 9 C.p. f-crystals, 3 tables.

The invention relates to the production of lactam hydrolysis by cyclization according to the tsya source compounds for obtaining polyamides (polyamide 6 from caprolactam).

One of the known methods of obtaining these lactams is to conduct hydrolysis by cyclization of the corresponding aminonitriles, more specifically unbranched aliphatic aminonitriles when passing them in the vapor phase with water over a solid catalyst.

Thus, in U.S. patent 2357484 described a method of producing lactam in the vapor phase, which consists in passing a mixture of water and aminonitriles over a dehydration catalyst, such as activated alumina, silica gel and titanium oxide or bartstra acid.

In U.S. patent 4628085 method for obtaining lactam in the vapor phase, which consists in contacting an aliphatic or aromatic aminonitriles and water with a catalyst based on silica in the form of spherical particles having a BET surface above 250 m2/g and an average pore diameter of less than 20 nm, typically in the presence of hydrogen and ammonia.

Typically, the catalysts used in the known methods, allow to obtain a good selectivity of transformation in the lactam. However, it often turns out that they are quick decontamination, which represents a very significant obstacle for the industrial implementation of these methods.

In the present invention proposes the new catalysts, which are leading to good selectivity reactions of aminonitriles in the lactam, have longer service life and, therefore, the need of regeneration occurs rarely.

More specifically, the invention consists in the method of producing lactam in the interaction in the vapor phase of aliphatic aminonitriles General formula (I)

N C-R-NH2< / BR>
in which

R is alkenyl radical containing 3 to 12 carbon atoms, with water in the presence of a solid catalyst, wherein the catalyst is a metal phosphate of General formula (II)

(PO4)nHhM, (Imp)p,

in which

M is a divalent, trivalent, tetravalent or pentavalent element selected in the groups 2A, 3b, 4B, 5B,6b, 7b, 8, 2B, 3A, 4A and 5A of the Periodic system of elements, or mixtures of several of these elements, or M = 0; Imprepresents a primary sealing compound consisting of alkali or alkaline earth metal or mixtures of several of these metals are associated with a counterion to provide electrical nitride impregnating agent Impand impregnated (PO4)nHhM.

Among aminonitriles formula (I), the most important are those that lead to lactams, employees source material for obtaining polyamides 4, 5, 6 and 10, i.e., those in the formula which the symbol R denotes a linear alkalinity radical having 3, 4, 5, or 9 carbon atoms. The preferred compound of formula (I) is 6-aminocaproate (or Epsilon-cupronickel), which leads to the caprolactam, in the polymerization of the polyamide 6.

Among the metals of groups 2A, 3b, 4B, 5B, 6b, 7b, 8, 2B, 3A, 4A and 5A of the Periodic system of elements can result, for example, beryllium, magnesium, calcium, strontium, barium, aluminum, boron, gallium, indium, 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.

Among the lanthanide phosphates can distinguish the first family, which groups the orthophosphate light rare earths, also called cerium rare earths, including lanthanum, cerium, praseodymium, neodymium, samarium and europium. These orthophosphate are dimorphic. They have hexagonally of lanthanide phosphates consists of orthophosphate gadolinium, terbium and dysprosium. These orthophosphate have the same structure as the orthophosphate cerium rare earths, but also has a third crystal phase quadratic structure at high temperature (about 1700oC).

The third family of lanthanide phosphates consists of orthophosphate heavy rare earths, also called yttrium rare earths including yttrium, holmium, erbium, thulium, ytterbium and latency. These compounds crystallize only in quadratic form.

Among the different families of the above orthophosphate rare earths preferred can be called orthophosphate cerium rare earths.

You can use a metal phosphate of formula (II), which are mixtures of phosphates few of the previously mentioned metals, or mixed phosphates of several of the previously mentioned metals, or mixed phosphates of one or more of the previously mentioned metals and one or more other metals, such as alkaline or alkaline earth metals.

Counterions included in the formula impregnating compound Impare the main. You can, for example, to use ions of hydroxide phosphate, monopotassium phosphate, secondary key is.

The molar ratio of p is preferably lies between 0.02 and 0.2.

If we start from the usual methods of preparation of phosphates (such as described, for example in "PASCAL P. Nouveau traitÚ de Chimie minerale", so X (1956), pages 821-823 and in "GMELINS Handbuch der anorganischen Chemie" (8th ed.), so 16(C), pages 202-206 (1965), one can distinguish two main ways of obtaining phosphates. On the one hand, the precipitation of the soluble metal salt (chloride, nitrate) primary acidic ammonium phosphate or phosphoric acid. On the other hand, dissolution of the oxide or metal carbonate (insoluble) phosphate acid, usually by heating, with subsequent sedimentation.

Precipitated phosphates obtained in accordance with one of the specified paths, can be dried, treated with an organic base (such as ammonia) or mineral base such as the hydroxide of an alkali metal) and can be subjected to calcination, these three operations can be performed in the order shown or in a different order.

A metal phosphate of formula (II) where the symbol p is greater than 0, can be obtained by impregnating compounds (PO4)nHhM received in accordance with one of the previously described methods, a solution or suspension of Impin volatile dissolve the more soluble and when the connection (PO4)nHhM is freshly prepared.

So, expedient way of obtaining phosphates of the formula (II) is:

(a) the implementation of the synthesis of compounds (PO4)nHhM, then preferably without selection (PO4)nHhM from the reaction environment;

b) enter impregnant Impin the reaction environment;

C) optionally, separating the residual liquid from the solid reaction product;

g) is dried and optionally calcined.

Performance characteristics of the catalyst of formula (II) and, in particular, its resistance to deactivation can be further enhanced by calcination. The temperature of calcination is advisable to lie between 300 and 1000oC, preferably between 400 and 900oC. the duration of the calcination can be varied within wide limits. As an example, it can be usually a time between 1 and 24 hours

Among the preferred catalysts of formula (II) for the method of the invention can lead to more concretely, lanthanum phosphate, calcined phosphate of lanthanum, the lanthanum phosphate associated with the derived caesium, rubidium or potassium hydroxide, calcined cerium phosphate, cerium phosphate, associated with the connection of cesium is osvat aluminum, associated with the connection of cesium, rubidium or potassium hydroxide, calcined phosphate, niobium, niobium phosphate associated with the connection of cesium, rubidium or potassium hydroxide, calcined acidic zirconium phosphate, acid phosphate of zirconium associated with the connection of cesium, rubidium or potassium.

Usually the catalyst is used in the form of powder, tablets, pellets or extrudates, this form if necessary can be obtained by using a binder. In some cases it may be advantageous to at least a portion of the free volume of the reactor was filled with an inert solid product, such as, for example, quartz, in order to facilitate the evaporation and dispersion of the reactants.

The hydrolysis reaction with the cyclization requires water. The molar ratio of water and used aminonitriles is usually between 0.5 and 50, preferably between 1 and 20.

Aminonitriles and water can be introduced into the reaction in the form of their mixtures in the vapor state or they may be introduced into the reactor separately. It is possible to conduct a preliminary evaporation of the reagents, which then circulate in the mixing chamber.

You can without inconvenience to use any inert gas as a carrier, such as nitrogen, goby reagents were in the form of vapour. Usually it is between 200 and 450oC, preferably between 250 and 400oC.

The contact time between aminonitriles and the catalyst is not critical. It can vary depending on, for example, from the used temperature. Is the preferred contact time is from 1 to 200, even more preferably it ranges from 50 to 100 C.

Pressure is not critical way. So, you can work at a pressure of from 10-3up to 200 bar. Preferably the process is conducted at a pressure of from 0.1 to 20 bar.

It is not excluded the use of a solvent inert under the reaction conditions, such as, for example, alkane, cycloalkane, aromatic hydrocarbon, or one of those hydrocarbons previously halogenated, and thus to have a liquid phase in the reaction stream.

The following examples illustrate the invention.

Example 1-6. In a cylindrical reactor of pericoloso glass with a capacity of 20 ml, situated vertically and provided with means for heating, the holes for the supply and withdrawal of gas flows and introduction of reagents sequentially load 10 ml of quartz, 1 ml of catalyst in powder form 0,8 - 1,25 Ám (the nature of the catalyst decree is in air flow (flow rate 1.5 l/h) for 2 hours Then the reactor is cooled to 320oC (selected reaction temperature and passed a current of nitrogen with a flow rate of 1 l/h).

Then injected using a pump a mixture of 6-aminocaproate (DCA) and water (mass ratio of 50/50 or the molar ratio of water to DCA is 6.2). The rate of introduction of the mixture of 1.2 ml/h

At the exit of the reactor vapor condenses in a glass trap at room temperature for 2 h

The final reaction mixture was analyzed by gas chromatography.

Determine the degree of transformation (TT) aminoacetonitrile, output (RT) caprolactam (CPL) in relation to developed aminoacetonitrile and activity of the catalyst, measured in grams of the resulting caprolactam/ml of catalyst h

The results are shown in table 1.

Examples 7-9. Repeat examples 1 to 9, following the increase in the activity of various catalysts over time to 35 hours

In table 2 below, the activity of each catalyst for increasing reaction times (ND = not determined).

Examples 10 and 11. Repeat example 1 in the same conditions, but carrying out the hydrolysis reaction by cyclization under different temperature is 1.

Comparative experience A.

Repeat example 1, replacing phosphate Za on silica (sold under the trade name Aerosil 200), calcined for 16 h at 600oC.

Working conditions are the same as in example 1 (temperature 320oC, the molar ratio of water/DCA 6,2, duration 2 h).

Get the following results:

TT DCA - 17.6 PER CENT;

RT KPL - 53%;

The activity of the catalyst (0.04 g KPL/ml of catalyst h

The silicon oxide gives a low yield of caprolactam and has a very low activity.

1 1. The method of producing lactam interaction in the vapor phase of aliphatic aminonitriles General formula I 6 N = C - R - NH2, 1 in which R is alkilinity radical having 3 to 12 carbon atom, 1 with water in the presence of a solid catalyst, wherein the catalyst is a metal phosphate of General formula II 6 (PO4)nHhM(Imp)p, 1 in which M is a divalent, trivalent, tetravalent or pentavalent element selected in the groups 2A, 3b, 4B, 5B, 6b, 7b, 8, 2B, 3A, 4A and 5A of the Periodic system of elements, or a mixture of several of these elements, or M - O; 4 Imp- the main sealing connection status is divaina, to provide electrical neutrality; 4 n = 1,2 or 3; 4 h = 0,1 or 2; 4 p is a number selected from 0 and 1/3, and the corresponding molar ratio between the impregnating agent Impand impregnated (PO4)nHhM. 2 2. The method according to p. 1, characterized in that aminonitriles General formula I is 6-aminocaproate. 2 3. The method according to p. 1 or 2, characterized in that in formula II phosphates of metals of groups 2A, 3b, 4B, 5B, 6b, 7b, 8, 2B, 3A, 4A and 5A of the Periodic system of elements represented by M, is chosen among beryllium, magnesium, calcium, strontium, barium, aluminum, boron, gallium, indium, yttrium, lanthanides, such as lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium, as well as zirconium, titanium, vanadium, niobium, iron, germanium, tin, bismuth. 2 4. The method according to PP. 1 to 3, characterized in that the use of phosphates of the formula II, which are a mixture of phosphates of several metals M, or mixed phosphates of several metals M, or mixed phosphates containing one or more metals M and one or more other metals, such as alkaline or alkaline earth metals. 2 5. The method according to PP.1 to 4, characterized in that the counterions included in SIDA, phosphate, monopotassium phosphate, secondary acid phosphate, chloride, fluoride, nitrate, benzoate, oxalate. 2 6. The method according to PP.1 to 5, characterized in that the molar ratio of p is preferably equal to 0,02 - 0,2. 2 7. The method according to PP.1 - 6, characterized in that the catalyst of the formula II is subjected to calcination at a temperature of 300 - 1000C, preferably 400 - 900C. 2 8. The method according to PP.1 to 7, characterized in that the catalyst is more specifically selected from among lanthanum phosphate, calcined phosphate of lanthanum, lanthanum phosphate, associated with the derived caesium, rubidium or potassium hydroxide, calcined cerium phosphate, cerium phosphate, associated with the connection of cesium, rubidium or potassium, samarium phosphate associated with the connection of cesium, rubidium or potassium, aluminum phosphate, aluminum phosphate, associated with the connection of cesium, rubidium or potassium hydroxide, calcined phosphate, niobium, niobium phosphate associated with the connection of cesium, rubidium or potassium hydroxide, calcined monopotassium phosphate zirconium, monopotassium phosphate zirconium associated with the connection of cesium, rubidium or potassium. 2 9. The method according to PP.1 to 8, characterized in that the molar ratio between water and aminonitriles, which came in the reaction is between 0,e 200 - 450C, preferably 250 to 400C.

 

Same patents:

FIELD: organic chemistry, chemical technology.

SUBSTANCE: invention relates to technology for preparing caprolactam by the cyclization reaction of derivatives of aminocaproic acid. Method is carried out by cyclizing hydrolysis of compound chosen from the group comprising aminocaproic acid esters or amides, or their mixtures. The process is carried out in the presence of water, in vapor phase at temperature 200-450°C in the presence of a solid catalyst comprising of aluminum oxide that comprises at least one macroporosity with pores volume corresponding to pores with diameter above 500 Å taken in the concentration 5 ml/100 g of above. Preferably, the specific square of catalyst particles is above 10 m2/g and the total volume of pores is 10 ml/100 g or above wherein pores volume corresponds to pores with diameter above 500 Å is 10 ml/100 g or above. Invention provides improving the process indices due to the improved properties of the solid catalyst.

EFFECT: improved preparing method.

5 cl, 2 ex

FIELD: chemistry.

SUBSTANCE: present invention relates to a method for synthesis of caprolactam from alkylcyanovalerate which involves bringing alkylcyanovalerate into contact with hydrogen in gaseous state in the presence of a hydrogenation catalyst and a ring formation catalyst, and treatment after condensation of a gaseous stream containing the formed lactam in order to separate ammonium which may be present, the formed alcohol and/or the caprolactam solvent and extraction of caprolactam, where the hydrogenation catalyst includes a metal element or a mixture of metal elements selected from a group containing an active metal element in form of iron, ruthenium, rhodium, iridium, palladium, cobalt, nickel, chromium, osmium and platinum or several metals from this list, and the ring formation catalyst is porous aluminium oxide.

EFFECT: obtaining caprolactam without intermediate separation of alkylaminocaproate.

10 cl, 5 ex, 1 tbl

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