RU2307120C2 - Production of 1,5-diaminonaphthalene - Google Patents

Abstract

FIELD: organic chemistry.

SUBSTANCE: claimed method includes reduction of 1,5-dinitronaphthalene with hydrogen in presence of heterogeneous catalyst in medium of organic solvent at elevated temperature and pressure in recirculated apparatus. Reaction zone of this apparatus is filled with high-porous block catalyst comprising of alumina-based carrier and active components such as metal palladium and sulfated zirconia in amount of 0.1-3 mass % and 5-8 mass %, respectively based on carrier mass. As organic solvent aniline or mixture thereof with 1,5-diaminonaphthalene may be used. Compound of present invention is useful as synthetic intermediate of polymer materials, physiologically active substances, dies, etc.

EFFECT: simplified process without steps of filtration and preliminary catalyst grinding; product of high quality and high yield.

2 cl, 1 tbl, 9 ex

Description

The present invention relates to chemical technology, in particular to methods for producing aromatic amines - important intermediate products in the synthesis of polymeric materials, dyes, physiologically active compounds and a number of other valuable chemical products.

1,5-Diaminonaphthalene (1,5-DAN) is widely used in various fields of technology, although the main direction of its use is the production of polyisocyanates (Desmodur (R) 15) and various polymeric materials based on it.

For a long time, the main method for producing amino derivatives of naphthalene was the reduction of the corresponding nitro compounds with metal sulfides (Berkman B.E. Industrial synthesis of aromatic nitro compounds and amines. M: Chemistry, 1964, p.242-273). Later, various reducing agents have been proposed for this purpose, in particular hydrazine (Pat. Japan 56059738, 1981).

The most widely used are catalytic reduction processes of 1,5-dinitronaphthalene (1,5-DNN) with molecular hydrogen (Pat. Japan 4154745, 1992, Pat. Great Britain 1499699, Pat. USA 4026944, 1977, Pat. Germany 2438542 and 2432015 , 1974). In these processes, mainly metals of the VIII group of the Table of D.I. Mendeleev were used as catalysts.

In the prototype (US Pat. US 4,026,944), diaminonaphthalenes are prepared by reacting the corresponding dinitronaphthalenes with hydrogen in the presence of a heterogeneous reduction catalyst in an organic solvent. Powders of skeletal nickel and / or iron or a platinum group metal on activated carbon are used as a catalyst. The process is carried out in a reactor with vigorous stirring, pressure up to 50 MPa and a temperature of 20-180 ° C. The resulting solution of the amino compound is filtered off from the catalyst, separated from the reaction water and sent to the selection of the target product.

The main disadvantages of the prototype is grinding during the process of a powder catalyst, which leads to a decrease in the activity of the latter and losses during filtration, as well as the need for the filtering stage itself.

The invention is aimed at eliminating the grinding of the catalyst and the stage of separation of the catalyst from the reaction mass in the process of obtaining 1,5-DAN. This is achieved by using a stationary catalyst with high catalytic activity.

The invention consists in a method for producing 1,5-diaminonaphthalene by reacting 1,5-dinitronaphthalene with hydrogen in the presence of a heterogeneous reduction catalyst in an organic solvent at elevated temperature and pressure, characterized in that the process is carried out in a circulating apparatus, the reaction zone of which is filled with highly porous block a catalyst consisting of a carrier based on aluminum oxide and active components - metallic palladium and sulfated zirconium oxide, mass which make up 0.1-3% and 5-8% of the mass of the carrier, respectively. As follows from the essence of the invention, we propose to use, instead of a powder catalyst based on skeletal nickel or palladium / platinum on coal, a stationary (made in the form of a block filling the entire reaction zone) catalyst based on high-strength cellular alumina with a porosity of 85-97%, to the surface which deposited metallic palladium in an amount of 0.1-3% by weight of the carrier and sulfated zirconium oxide in the amount of 5-8% by weight of the carrier.

The process is proposed to be carried out in a circulation apparatus, consisting, for example, of two vertical cylindrical zones (reaction and recirculation), connected by overflows in the lower and upper parts. This design of the apparatus allows the recirculation of the reaction mass due to the density difference of the gas-liquid mixture in the reaction zone and the liquid in the recirculation.

The intensity of mixing in the reaction zone is ensured by the presence in the catalyst of transport pores of small diameter and high speed gas-liquid mixture formed when hydrogen is supplied to the flow of a circulating solution. If necessary, the circulation can be increased due to the operation of the pump dosing the nitro compound solution.

The use of a circulating apparatus makes it possible to maintain a low concentration of 1.5-days in the reaction zone. At a high content of 1,5-DN in the solution, a sharp decrease in the process rate is observed due to its adsorption on the surface of the catalyst. At the same time, 1,5-DAN formed during the reduction process increases the solubility of 1,5-DNN.

Obtaining 1,5-DAN is carried out in an organic solvent (toluene, aniline) at a temperature of 30-120 ° C and a pressure of 0.1-1 MPa. Isolation of the resulting 1,5-DAN in the form of crystals occurs when the reaction mixture is cooled below 30 ° C.

After separation of the product, the filtered mother liquor can be used to prepare a solution of 1,5-DNN, going for recovery. At the same time, the concentration of 1,5-DAN in the solution increases and its crystallization upon cooling is facilitated. At the same time, in the presence of 1,5-DAN, the probability of 1,5-DNN falling out of the dosed solution decreases.

Examples 1-7

In a vertically mounted heated cylindrical reactor with an internal diameter of 50 mm and a volume of 400 ml, a highly porous cellular catalyst is placed in the form of a single unit with a volume of 95 ml fixed in the middle of the apparatus. The mass of the catalyst is 21.1-21.9 g, the density is 0.22-0.23 g / cm ³ , the porosity is 94-95%. The active part of the catalyst consists of activated zirconium oxide in an amount of 6-8% by weight of the catalyst, the content of palladium metal is 0.16% by weight of the catalyst. A solution of 1.5 g of dinitronaphthalene in 90 ml of aniline is loaded into the reactor and heated to the reaction temperature. Then the reactor is transferred from vertical to horizontal (to ensure contact of the solution with the catalyst) and include reciprocating mixing. The results are presented in the table.

Table Example No. The temperature of the experiment, ° C Pressure, MPa Half-time *, s The load on the catalyst **, hour ^-1 one 90 0.7 180 0.46 2 84 0.9 107 *** 0.78 3 90 0.9 140 0.92 *** four 95 0.9 102 0.84 5 89 1,1 95 0.88 6 91 1.3 86 0.97 7 92 1,5 74 1.13 * half-time - the time of absorption of 50% hydrogen from its total consumption in the reaction; ** load on the catalyst - the amount of g of 1,5-DNN, reacting to 1 g of catalyst per unit time; *** full conversion time - 8 minutes; **** in the experiment used - 2, 2 g of dinitronaphthalene

After the completion of the experiments, the obtained reaction masses were analyzed by GLC. Only three peaks are present on the chromatograms: aniline, 1,5-DNN and 1,5-DAN. The content of 1,5-DNN in products is less than 0.5%.

Example 8

In the catalytic zone of the circulation circuit, which consists of two vertical pipes with a diameter of 50 mm and a height of 6 m, connected by flows at the top and bottom (total volume of the circuit is 25 l), 1250 g of catalyst was placed in the form of a solid block 2.5 m long. Corundum based catalyst contains 3% metallic palladium and 7% sulfated zirconia (catalyst density 0.25 g / cm ³ , porosity 93%). 20 L of aniline was poured into the circuit and at the same time, the supply of a 5% solution of DNN in aniline and hydrogen was started. The flow rate of the solution is 2000 ml / h, the pressure is 0.5 MPa, the temperature in the lower part of the reaction zone is 95 ° C, in the upper - 105 ° C, the continuous operation time is 24 hours. A total of 2.4 kg of 1.5-days was dispensed. The content of 1,5-DN in the reaction product was 0.006-0, 030% in the course of the experiment. Upon cooling the reaction mass obtained 1.6 kg of 1,5-DAN - raw, containing 75% of the main product, 0.18% - 1,5-DN, the rest is aniline. Mp obtained after separation of the aniline product 187-188 ° C. Yield 69% (1,5-DAN remaining in the aniline solution was not taken into account when calculating the yield).

Example 9

The installation for preparation and the catalyst are the same as in Example 8. After filling the system with a 5% solution of 1,5-DAN in aniline, the flow of a 5% solution of 1,5-DNN in a 5% solution of 1,5-DAN in aniline and hydrogen is simultaneously started . The flow rate of the solution is 2000 ml / h, the pressure is 0.53 MPa, the temperature in the lower part of the reaction zone is 97 ° C, in the upper - 107 ° C, the continuous operation time is 29 hours. A total of 2.9 kg of 1.5-days was dispensed. The maximum concentration of 1,5-DAN in the reaction mass was 11%, the content of 1,5-DAN in 1,5-DAN during the experiment ranged from 0-0.5%. When the reaction mixture was cooled to 20 ° C, 1.9 kg of 1,5-DAN, a crude product containing 75% of the main product, 0.1% of 1,5-DAN, the rest was aniline, was obtained. Mp obtained after separation of the aniline product 187.5-188 ° C. Yield 67%. With partial distillation of aniline from the mother liquor, 0.7 kg of 1,5-DAN (mp 187-188 ° C) was additionally obtained and the total yield increased to 92%.

Claims (2)

1. The method of producing 1,5-diaminonaphthalene by the interaction of 1,5-dinitronaphthalene with hydrogen in the presence of a heterogeneous reduction catalyst in an organic solvent at elevated temperature and pressure, characterized in that the process is carried out in a circulating apparatus, the reaction zone of which is filled with a highly porous block catalyst, consisting of a carrier based on aluminum oxide and active components - metallic palladium and sulfated zirconium oxide, the masses of which are 0.1-3 and 5-8% by weight of Itel, respectively. 2. The method according to claim 1, characterized in that aniline or a mixture thereof with 1,5-diaminonaphthalene is used as an organic solvent.