The method of obtaining cyclic lactams
(57) Abstract:Cyclic lactams obtained by hydrolysis of aliphatic NITRILES aminocarbonyl acids in the liquid phase in the reactor with a fixed bed of heterogeneous catalyst which does not contain components that are soluble in the working conditions of the process. Use a solution of nitrile aminocarbonyl acid concentration of 1-50 wt.% in water or mixtures of water with organic solvent. Caprolactam is obtained from the nitrile-6-aminocarbonyl acid. Easier separation of the catalyst from the liquid reaction products, reducing the amount of catalyst increases the yield of the final product. 4 C.p. f-crystals, 4 PL. The invention relates to a new method of obtaining cyclic lactams by transformation of NITRILES aminocarbonyl acid with water in the presence of catalysts.From U.S. patent 4 628 085 known transformation of the nitrile 6-aminocaproic acid with water in the gas phase in the pure silica gel at 300oC. the Product of this proceeding quantitatively transformation is caprolactam with an initial selectivity of 95%, however, there has been a rapid decline of productivity and selectivity. A similar method is described in U.S. patent 4 023 625, according to which wymiana, water and a carrier gas, is passed through a catalyst bed containing silica gel and a mixed oxide of copper(chromium), barium and titanium. When the degree of conversion of 85% caprolactam get with a selectivity of 91%. Also there is a rapid de-activated catalyst.The object of U.S. patent 2 301 964 is not catalytic conversion of nitrile 6-aminocaproic acid to caprolactam in the aqueous solution at 285oC. the Output is below 80%.In French patent 2 029 540 describes how cyclization of nitrile 6-aminocaproic acid to caprolactam using catalysts, and the catalysts used metallic zinc or copper powder, and the oxide, hydroxide, halides, cyanides rubidium, lead, mercury or elements with atomic numbers 21-30 or 39-48. These catalysts are used periodically operating the autoclave in the form of a suspension of the catalyst. Complete separation of the catalyst from the target product of caprolactam, however, is problematic, as caprolactam can form a connection with the soluble part of the applied metal or may be formed of small particles under mechanical stirring.The objective of the invention p the oil acids with water in the presence of catalysts, which does not have the above disadvantages, gives high yield and selectivity and allows you to carry out the process continuously.In addition, it was necessary to spend as little as possible of the catalyst. It was necessary also to overcome the problem of separation arising from the conduct of processes in suspension and caused by complexation of soluble catalysts with components of the reaction mixture or fine particles, which are formed due to large mechanical loads under stirring.This task according to the invention is solved in that the transformation is carried out in the liquid phase in the reactor with a fixed bed in the presence of heterogeneous catalysts, in which the operating conditions of the process do not contain soluble components. Heterogeneous catalysts are in a fixed bed, through which is continuously in the form of irrigation or by recharge from the bottom to pass the reaction mixture.Preferred embodiments of the present invention are characterized in the dependent claims.The starting compounds in the method according to the invention are NITRILES aminocarbonyl acids, preferably is employed, at least 3, preferably at least 4. R1and R2can be fundamentally Vice of any kind, and must be ensured that the deputies had no impact on the target cyclization reaction. Preferably R and R independently of one another denote a group C1-C6-alkyl or C5-C7-cycloalkyl, or C1-C12-aryl.Especially preferred parent compounds are NITRILES aminocarbonyl acids of General formula
m has a value of 3, 4, 5 or 6, in particular 5. For m = 5 the starting nitrile compound is 6-aminocaproic acid.According to the method according to the invention described above NITRILES aminocarbonyl acids turn with water in the liquid phase with the use of heterogeneous catalysts in a cyclic lactam. When using NITRILES aminocarbonyl acids of the formula (I) obtain the corresponding cyclic lactams of the formula (II)
< / BR>and
n, m, R1and R2have the above values. Particularly preferred such lactams, in which n=0 and m has a value of 4, 5 or 6, especially 5 (in this case, get caprolactam).The transformation of Khujand oC; the pressure is in General from 1 to 250 bar, preferably from 5 to 150 bar, and you should pay attention to the fact that the prevailing part of the reaction mixture in the working conditions of the process was liquid. The reaction time is from 1 to 120 minutes, preferably from 1 to 90 minutes. In some cases, the reaction time from 1 to 10 minutes is enough.1 mol of nitrile aminocarbonyl acid is used in the General case, at least 0.01 mol, preferably from 0.1 to 20 mol, and particularly preferably from 1 to 5 mol of water.Mainly nitrile aminocarbonyl acid is used in the form of a solution in water with a concentration of from 1 to 50 wt.%, in particular from 5 to 50 wt.%, particularly preferably from 5 to 30 wt.% (and here the solvent is simultaneously a component of the reaction) or in the form of a solution in a mixture of water and solvent. The solvent can be called alcohols, such as methanol, ethanol, norms. and isopropanol, standards., ISO - and tert-butanol, polyols such as diethylene glycol and tetraethylene glycol, hydrocarbons such as petroleum ether, benzene, toluene, xylene, lactams, such as pyrrolidone or caprolactam, or substituted alkyl lactams, such as N-methylpyrrolidone acids with 1 - 8 carbon atoms. In the reaction medium may also contain ammonia. Of course, you can also apply a mixture of organic solvents. In some cases, particularly preferred are mixtures of water and alcohols in a weight ratio of water to alcohol is from 1:99 to 75:25, predominantly from 1:99 to 50:50.Likewise possible in principle to apply the NITRILES aminocarbonyl acids as components of the reaction and as a solvent.As heterogeneous catalysts can, for example, use: acid, basic and amphoteric oxides of elements of the second, third or fourth main group of the Periodic system of elements, such as calcium oxide, magnesium oxide, boron oxide, aluminum oxide, tin oxide or silicon dioxide in the form of pyrogene obtained silicon dioxide, silica gel, kieselguhr, quartz or mixtures thereof, and oxides of metals of the second and sixth side groups of the Periodic system of elements, such as titanium oxide, amorphous, as anatase or rutile, zirconium oxide, zinc oxide, manganese oxide or mixtures thereof. Also applicable oxides of the lanthanides and actinides, such as cerium oxide, thorium oxide, praseodymium oxide, samarium oxide, mixed oxide of rare earth IU the oxide of niobium, iron oxide, chromium oxide, molybdenum oxide, tungsten oxide or mixtures thereof. You can also apply a mixture of these oxides. Apply some sulfides, selenides and tellurides, such as zinc telluride, selenide, tin, molybdenum sulfide, tungsten sulfide, Nickel sulfide, zinc sulfide and chromium sulfide.In the above compounds can be added or they are suitable. may contain compounds of elements of the first and the seventh and the seventh main group of the Periodic system.Furthermore, it can be described as suitable catalysts zeolites, phosphates and heteroalicyclic, as well as acidic and alkaline ion exchangers, such as for example Nafion.If necessary, these catalysts can each contain up to 50 times the weight. % of copper, tin, zinc, manganese, iron, cobalt, Nickel, ruthenium, palladium, platinum, silver or rhodium.Applied catalysts, depending on their composition can be fully active catalysts or supported catalysts. For example, titanium dioxide can be applied in the form of charge particles or it can be applied as a thin layer on a carrier. For the deposition of titanium dioxide on a carrier such as silica gel, aluminum oxide or zirconium oxide Pisa organic compounds of titanium, such as isopropyl titanium or butyl titanium, or by hydrolysis of titanium tetrachloride or other titanium-containing inorganic compounds. You can also apply the Sol containing the titanium oxide Sol.The advantage of the process in a fixed bed is, on the one hand, the ability to carry out the cyclization simple way continuously. On the other hand, unexpectedly achieved high yields and selectivity, which allows small reaction times with very high bandwidth. As the applied catalysts according to the data available at the present time, have a high service life, requires extremely small amounts of catalyst. The problem of separation arising from the conduct of processes in suspension and caused by complexation of soluble catalysts with components of the reaction mixture or fine particles, which are formed due to large mechanical loads under stirring, during the process in a fixed bed completely disappear.Examples
In a heated tubular reactor with a capacity of 25 ml (diameter 6 mm, length 800 mm), filled with titanium dioxide (anatase) in the form of charge is atie in weight proportions, listed in the table. The product stream leaving the reactor were analyzed by gas chromatography and liquid chromatography under high pressure (ghvd). Results are also presented in table. 1
Comparative example.In conditions similar to those described in example 1 was carried out by transformation into a solution containing 10% nitrile aminocaproic acid, 6.4% of water and 83.6% of ethanol without heterogeneous catalyst at 250oC and a reaction time of 30 minutes in a hollow tubular reactor. The degree of conversion was 28% and the selectivity to caprolactam - 74%.Examples 7 to 16.Analogously to examples 1 to 6 in the same tubular reactor was carried out by examples 7 to 16, and applied 13.3 g of titanium dioxide (PL. 2).Examples 17 to 22.Similarly to examples 1 to 6 in the same tubular reactor was carried out by examples 17 to 22, and used 20 g of titanium dioxide (PL. 3)
Examples 23 to 27.Similarly to examples 1 to 6 in the same tubular reactor was carried out by examples 17 to 22, and applied different catalysts (table. 4). 1. The method of obtaining cyclic lactams by transformation of NITRILES aminocarbonyl acids with water when applying katalysatoren catalysts, which under the operating conditions of the process do not contain soluble components.2. The method according to p. 1, wherein the transformation is carried out at a temperature of 140 to 320oC.3. The method according to PP. 1 and 2, characterized in that use nitrile aminocarbonyl acid of General formula
moreover, m is 3, 4, 5 or 6.4. The method according to p. 3, characterized in that as nitrile aminocarbonyl acid use nitrile 6-aminocaproic acid.5. The method according to PP. 1 to 4, characterized in that the used solution of nitrile aminocarbonyl acid in water or in a mixture of water and an organic solvent at a concentration of 1-50 wt.%.
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
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