Method of producing and cleaning pyromellitic anhydrite

FIELD: chemical engineering.

SUBSTANCE: method comprises step-by-step oxidizing of durol up to pyromellitic acid by oxygen in acetic acid environment at high temperature and pressure in the presence of salts of heavy metals and haloid compositions and subsequent cleaning the solution produced by means of hot filtering and solidification.

EFFECT: improved method.

2 dwg, 2 tbl, 18 ex

 

The invention relates to organic synthesis, in particular to the synthesis and purification pyromellitates of dianhydride (PMDA) is an extremely valuable Monomeric raw material for the production of heat-resistant polyimides, alkyd resins, effective plasticizers, water-soluble varnishes, lubricants, adhesives, cured epoxy resins, emulsifiers and dyes.

Known methods for producing PMDA based on the oxidation of durene as headspace (T≥400° (C)and liquid phase (T≤250° (C) methods, followed by purification of PMDA raw recrystallization in different nature organic solvents. When using a vapor-phase high-temperature oxidation of durene get PMDA raw immediately at the exit of the mass of the reactor, as are formed pyromellitate acid (PLA) in these conditions quantitatively dehydratases, and in the case of liquid-phase processes in the reactor exit receive PMK raw, which dehydration in the liquid phase to PMDA raw, and then subjected to purification.

There is a method of oxidation of durene to pyromellitic acid [U.S. Pat. U.S. No. 4755622, 1988] by molecular oxygen in the lower aliphatic acid in the presence of Co-Mn-Br catalyst with the addition of salts of zirconium or their otsutstvie the essence of which is that the reaction is carried out in two stages in the temperature in which Arvale 100-250° With the first stage of injected from 10 to 35% of the bromine from the total amount used in the process, and the second stage remaining. The temperature in the first stage is supported in the interval 125-165°and in the second stage, the temperature was raised to ˜175 to ˜250°C.

The main disadvantage of this process is the relatively high reaction temperature in the second stage (250° (C)that, as is well known, leads to destructive processes as durene, and solvent (CH3COOH) with their inevitable loss due to combustion and the formation of high-boiling side products of oxidative condensation and destruction.

Known purification method of PMDA by treatment and washing with an organic solvent consisting of a lower aliphatic ketone and isopropyl ether, cyclohexane, aliphatic hydrocarbon mixture or a saturated aliphatic hydrocarbon, C5-C10or a mixture of the ester of acetic acid with lower aliphatic ketone or Quaternary butanol in suspension with stirring at room temperature [U.S. Pat. Germany No. 1768881, 1972]. This low-temperature method allows in terms of incomplete dissolution (suspension) to improve the quality of PMDA to the content of the main product is 99%. To further improve the quality requires multiple processing and washing you perechislennye solvents, what complicates the cleaning process and makes it largely preparative synthesis than industrial.

Also known cleaning method of PMDA by recrystallization from a mixture of dioxane and acetic anhydride containing 50% or less of acetic anhydride [U.S. Pat. Japan No. 45-4050, 1970]. The quality of the product, the content of the basic substance (˜99%) can be used to obtain polyimides by condensation with diamines. For further purification PMDA obtained after recrystallization, it is assumed thermal treatment at 240°C and above in order decay traces pyromellitic acid. The main disadvantage of this method is the low quality of the resulting product, which requires additional use of other physical or physico-chemical methods of purification.

The known method of increasing the efficiency of purification of PMDA raw, based on a combination of the processes of complexation of the purified product with an aromatic hydrocarbon and decomposition of the complexes [U.S. Pat. Germany No. 1274107, 1968]. The essence of the method lies in the fact that PMD raw mixed with an aromatic hydrocarbon (benzene, toluene, o-xylene, p-xylene or a mixture thereof), heated to the boiling temperature (100-200°C), filtered at this temperature and from the filtrate by cooling vykristallizovyvalas complexes of PMDA with aromaticspecialities, which are separated from the suspension by filtration method and decompose thermally in a temperature range of 100-200°With the purified pyromellitic dianhydride and aromatic hydrocarbons. The use of high ability PMDA for complexation with aromatic hydrocarbons, and the use of relatively simple method of thermal decomposition of the complexes on the components, made it possible to effectively clean PMDA of impurities that are formed during gas-phase oxidation of durene, and primarily from mechanical impurities (catalyst, solid heat carrier and others). If PMD receive liquid-phase method, the application of this method of cleaning is not sufficient to achieve the desired product quality (of 99.98%), because in the latter case, other are formed by the nature of the impurity - phthalide, acceptale, clearing from which a technique of forming a complex with its subsequent decay, is ineffective and insufficient. Essentially the main disadvantage of this method is that it is not universal, its application is limited and depends on the qualitative and quantitative composition of impurities in PMDA raw.

The known method based on the combination of the processes of complexation of PMDA with different nature aromatic hydrocarbons donor and the decomposition of the complexes in selective key is oradatabase hydrocarbon solvents or hydrocarbon solvents, with the holding capacity of impurities during the decomposition of the complexes such as gasoline, isooctane, benzene [U.S. Pat. Of the Russian Federation No. 956454, 1982]. The essence of this cleaning method is that as the initial use of PMDA raw, obtained by vapor-phase oxidation of durene and containing impurities in the number 2-99,5%, and aromatic hydrocarbons with molecular weight 134-202, ionization potential 8,15-7,38 eV and axial symmetry of the molecule, the content of impurities 7-37%, and the formation of the complex is carried out at a temperature of(-5)-(+80)°and equimolecular the ratio of pure substances, and decomposition of the complex is carried out at 15-85°in an organic solvent. Received PMDA recrystallized.

The main disadvantage of this method is the lack of universality, i.e. this method allows you to clean PMDA only from those impurities which are specifically formed during the oxidation of durene vapor-phase oxidation method in the region of 400-450°when such intermediate and by-products, such as aromatic aldehydes, phthalide and acceptablity, almost quantitatively thermally decompose and as major impurities are thermally stable aromatic anhydrite patterns products deeper oxytelinae transformation than is the case when the liquid-phase oxidation of durene in the field of 160-220°C.

At the same time, the ri implementation of synthesis of PMDA a vapor-phase method and the proposed method of its purification yield of the target product usually does not exceed 60-70%, this is caused by thermal degradation, oxidative condensation and simply with the process of "burning" the source of hydrocarbons and products of its transformation at the stage of synthesis of PMDA.

The closest in technical essence and the achieved results is a method for intramolecular anhydrides benzoldicarbonic acids (pyromellitimide of dianhydride, trimellitic and phthalic anhydrides) [U.S. Pat. RF SU 1584342, 1987 (prototype)]. The essence of the method consists in the following. Oxidation of durene is carried out in the liquid phase in the temperature range 100 to 220°With oxygen in an acetic acid medium in the presence of Co-Mn-Zr-Ni-Br catalyst with a ratio of bromine to total metals (2,5-8,0):1 and the Ni content of the total mass of metals of 0.5-8%. As compounds of bromine using HBr, CoBr2and/or MnBr2or NH4Br, which is administered at the beginning of the reaction in the amount of 36-65% in terms of Br, and upon reaching the reaction products 70-98% benzoldicarbonic acids enter the remaining number of bromine (220° (C) in the form of Hydrobromic acid in a mixture with aliphatic compound selected from group (a methyl ethyl ketone, acetic acid, pentadecanol faction and others) in the amount of 4,8-82,3% by weight of oxidized hydrocarbon. Received pyromellitic acid after removal from oxidate all liquid products are subjected Ter is the practical ameridial environment pseudocumene at a temperature 230-235° With obtaining PMDA. Significant disadvantages of this method include the following:

1) a large number of components oxidizing reagents and catalyst, are introduced into the synthesis process, which complicates both the schema of the main process, the auxiliary stage of their regeneration;

2) use pseudocumene as environment for ameridial and cleanup of generated PMDA in one stage is not sufficient to produce the desired product of high purity, providing high-quality polymer products used in modern engineering (electronics, aviation, missile systems);

3) application at the main stages of the oxidation of complex devices with mechanical stirring, operating in aggressive environments and at elevated temperatures and pressures, increases the cost of manufacture and operation, complicates the process.

Analysis of the foregoing methods of synthesis and purification of PMDA shows that obtaining high purity of the target product (≥of 99.98%) with acceptable for usual industrial output by source durene not less than 90% currently no: headspace method for the synthesis of PMDA and its cleaning method that combines the processes of complexation with aromatic hydrocarbons and decomposition of the complexes in oxygen-containing organic hydrocarbons, about especiay the achievement of the required quality PMDA, however, the output does not exceed 60-70%; liquid-phase process can provide a higher output PMK, PMD on the basis of up to 90%, however, the quality of the target product is not below of 99.98% can be achieved with known methods of cleaning PMDA.

To solve this problem, a new method of synthesis of high-purity intramolecular dianhydride pyromellitic acid, based on the sequential processes of liquid-phase oxidation of durene in the moderate temperature range (140-220° (C) to pyromellitic acid, ameridial PMK to PMDA with simultaneous partial purification, mainly from the catalyst complexes and intermediate (side and neoamerican) products followed by recrystallization of PMDA in the mixed solvent.

The purpose of the invention is to simplify the process and improve the quality of PMDA. This goal is achieved by the fact that as a halide compounds used kaleidotrope acid (Ha) number of HBr, HCl, HF in the form of binary, ternary mixtures (HBr+HCl), (HBr+HF), (HBr+HCl+HF) in a ratio of Br ions:Cl:F, equal 1:(0,15-1,0):(0,01-0,5), and/or HBr, and as the metal catalyst (MC) - salts of Mn, Co, Zn in the form of acetates, bromides, chlorides or fluorides the ratio of metal ions (Co+Mn):Zn = 1:(0,5-0,1) respectively, with a total value MK:SC = 1:(1,2-3), and the oxidation is carried out in 4 stages in emperature range 140-220° C and at a pressure of 2.0 to 3.0 MPa so that the temperature at each step increase by 10-15°and the pressure reduced to 0.2-0.3 MPa to excess pressure on the 4th level, exceeding the vapor pressure of the reaction mass not less than 0.25 MPa, and the reaction time at each stage in the limit of 20-60 minutes to reach the transformation of durene in pyromellitic acid in the range of 22-35%, 50-78%, 88-93%, 95-98%, respectively, and after separation of oxidation products coming out of the 4th stage, sequentially subjected to ameridial with simultaneous cleaning in pseudocumene by hot filtration of the resulting solution pyromellitic anhydride from insoluble metal complexes of catalyst residues and PMK with further cooling and release of the obtained complexes PMDA with PMC followed by purification by recrystallization in a mixed solvent consisting of benzene and ethyl acetate.

The simplification process is achieved by the use efficiency of a catalytic system consisting of a 3-component mixture of the metals Mn-Co-Zn in combination with a binary or ternary mixture of halide compounds (Br+Cl) and/or (Br+F) and/or (Br+Cl+F), providing a more selective stepwise transformation of durene in PMK in a moderate increasing temperature, due to the lower reactivity of the reacting is Reducto in the final stages, and more efficient continuous reactivation of deactivated forms of the catalyst binary mixture of strong proton acids.

Step catalytic oxidation of durene with continuous reactivation of deactivated forms of the catalyst eliminates the precipitation from a solution of the solid phase (catalyst complexes with pyromellitates, methyltrienolone and trimellitic acid), which allows the use of simple reaction apparatus without mechanical mixing device such as a bubble column reactors, shell-and-tube gas-lift apparatus that greatly simplifies the process flow, instrumentation process, making it more efficient from the point of view of the cost of construction and operation.

Improving the quality of PMDA is achieved by using an effective design process ameridial PMK in pseudocumene with simultaneous cleaning of the catalyst and organic impurities in the form of a solid phase intermediate and final products of oxidation by means of hot filtration found in mode and also using a mixture of benzene and ethylbenzene in the final stage of purification by recrystallization method.

List of drawings and other materials

Figure 1: scheme of the laboratory setup oxidation of durene to PMC.

Figure 2: scheme of the laboratory setup of ameridial PMK is cleaning PMDA.

Table 1: conditions and results of experiments on the oxidation of durene to PMC.

Table 2: conditions and results of experiments on ameridial PMK and cleaning PMDA.

The invention is illustrated by examples.

Example 1. Experiments are performed on the continuous steps (figure 1) with a gas-lift reactor (V=1.2 l), made of titanium VT1-0. The plant is equipped with a collection of the original reaction mixture (IRS-1), pump-dispenser IRS-2, the oxidation reactor 3, a condenser 4, a compressor 5, a collection of phlegmy 6, a collection of oxidate 7, the receiver 8, the analyzers on O2, CO, CO211, rotameters air flow 12, Instrumentation, instruments for measuring temperature, pressure, sampling device. Air after the compressor is subjected to cleaning and drying the alkali dust and oil in the gas dehumidifier 9, 10 before feeding into the reactor. The inert gas fed into the reactor from the cylinder 13. Charged to the reactor 104 g of durene, 650 g of 98%acetic acid, 2.6 g of Co(SLA)2×4H2O, 7,15 g Mn(SLA)2×4H2O 0,82 g Zn(OAc)2.

The initial reaction mixture is heated in a current of inert gas at R=2,6 MPa to 100°With, in the reactor serves the air in quantities of 12 l/min and through the capsule pour a solution of 3 ml of HBr and 1.15 ml of HCl in 22 ml of 98%acetic acid. Due to the heat released in the oxidation process, there is a rapid R is threw the reaction mass up to 165° C. the Temperature of the reaction support by removing heat through the wall of the reactor. Introduced additional acetic acid is removed from the reactor by evaporation and collecting the condensate in the collection of phlegmy.

After the final absorption of oxygen (oxidation time 35 minutes) for the rest of the steps of introducing additives HBr and HCl in acetic acid in the same quantities as in the first stage, with the temperature oxidation 180° (R=2,4 MPa), 195° (P=2.2 MPa), 205° (P=2.0 MPa) and time of oxidation equal to 25, 20 and 20 minutes respectively, the degrees of oxidation. The total oxidation time of 100 minutes. The contents of the PMC in the product 98 wt.%, TMK+TSK of 0.38 wt.%. Output PMK $ 94.2%.

After completion of the process of oxidate remove acetic acid and water by the method of parki and the selected oxidation products are sent for installation of ameridial (figure 2). Setting ameridial includes reactor angelization 18, a furnace for heating the contents of the reactor 17, the mold 15, the filter of the hot filter 16, Florentine vessel 19, the cooler-condenser to trap water 4 gas dryer 9, the container with the inert gas for feeding into the reaction zone 13.

In the reactor-angelization 18 load 100 g of the obtained product and 700 ml (UCS) pseudocumene create nitrogen pressure ˜3,6 kg/cm2and heated (17) the contents of the reactor with stirring to 230°C. In these the conditions for 1.5 hours are ameridial PMK. Obtained ameridial water in the form of condensate from the UCS is captured in the condenser 4 and enters the Florentine vessel 19, where, after stratification accumulates at the bottom and periodically drained, and UCS through the upper fitting merges continuously into the reactor and maintained the natural cooling of the solution to 190-200°when operating the mixer.

When the temperature of the solution 190-200°to separate the catalyst and insoluble impurities are filtered through a filter hot filter 16 in the mold 15, which when mixed and the temperature drops to 20°To conduct crystallization of PMDA, followed by the separation of the obtained crystals, PMDA. The precipitate obtained PMDA after filtering are loaded into the reactor 18, there pour 300 ml of benzene and 300 ml of ethyl acetate, create nitrogen pressure (P=5,6 kg/cm2and the reactor is heated with stirring to 140°C. In these conditions for 1 hour to conduct the dissolution of PMDA. After the dissolution of the heating of the reactor stop and lead a natural cooling of the solution to 100°C, after which the solution is drained through the filter of the hot filter 16 in the mold 15, which when mixed and reducing the temperature to 20°To conduct crystallization of PMDA with further filtering and drying the final product. The final paragraph is oduct (PMDA) with the content of the basic substance 99.91 per cent with a total yield 88.1 percent.

Example 2. The experience is conducted under the conditions of example 1 with the only difference that the ratio of ions (Co+Mn):Zn is reduced from 1:0.10 to 1:0,05. Under these conditions, the qualitative indicators of "raw" PMK on the content of the basic substance remained on the same level, however, the concentration of by-products trimellitic acid and criminology acid (TMK+TSK) increased from 0.38 to 0.45%, the yield decreased from 93.4 to 92,0%. Received PMDA content of 99.9% and a yield of 87.7 per cent.

Example 3 (comparative). The experience is conducted under the conditions of example 1 with the only difference that the ratio of ions (Co+Mn):Zn increases from 1:0.1 to 1:0.3 to. The increasing ratio of the amount of ions of Co and Mn to Zn to the specified limit output PMK decreased from 93.4 to 89,2%, as crude product has deteriorated in content PMK with 98,05 to 96,1%, and the content of by-products (TMK+TSK) from 0.38 to 0.99%. This indicates that Zn plays the role of the speed regulator of a number of stages leading to the formation of by-products: at low concentrations of the reduced content of by-products; at higher concentrations acts as a competitor with (Co+Mn) is the slow speed of the main reactions leading to the formation of the target product (CIP). Received PMDA with the content owner of 99.87% and output 85,9%.

Example 4. The experience is conducted under the conditions of example 1 with the only difference that the ratio Br:Cl vary from 1:0.3 to 1:0.15 in. Quality is about PMK and its output has fallen slightly, the content of the main product in the oxidation products decreased from 98 to 97%, the output PMK decreased from 93.4%to 93%. Received PMDA content of 99.2% and a yield of 87.9 per cent.

Example 5. The experience is conducted under the conditions of example 1 with the only difference that as halide compounds using ternary mixture containing HBr, HCl and HF in the ratio Br:Cl:F=1:0.15 to:0,1. The output of the PMK had risen 94,1%. Qualitative indicators crude PMK practically remained at the level of example 1, which used a binary mixture of halides. Received PMDA content 99,92% and yield of 88.5 percent.

Example 6. The experience is conducted under the conditions of example 1 with the only difference that the content of HCl is increased by changing the ratio Br:Cl of 1:0.3 to 1:0.5 in. Output PMK declined slightly by 0.7%, the content of PMC products of oxidation decreased with 98.0 up to 96.9%. Received PMDA with the content of 99.90 percent and access to 87.9%.

Example 7 (comparative). The experience is conducted under the conditions of example 6 with the only difference that the ratio Br:Cl changed from 1:0.4 to 1:2, i.e. the number of Cl with respect to Br increased in 2 times. Output PMK decreased significantly with 92,7 to 84%, the content of PMC products of oxidation decreased with up to 96.9 80,4%.

Ameridial and recrystallization is carried out in the conditions of example 1. The result: quality PMDA on the content of the basic substance of 99.85%, the total yield of 73.2 per cent.

Example 8. The experience is conducted under the conditions of example 1 with the only difference, is that instead of Cl use F in the ratio Br:F=1:0,1. The output of the PMC and its quality indicators in the context of reduced 3 times the number of F compared to Cl (in experiment 2 Br:Cl=1:0,3) remained almost at the same level, which indicates that increased the promoting ability of F compared to Cl.

Ameridial and recrystallization is carried out in the conditions of example 1 with the only difference that the solvent in the recrystallization was used again pseudotumor, the use of which does not significantly reduce remaining after ameridial impurities. Result: the content of the basic substance 99.4%of the total output stages of oxidation and ameridial 85,6%.

Example 9. The experience is conducted under the conditions of example 8 with the only difference that the ratio Br:F changed from 1:0.1 to 1:0.5 in. The quality indicators PMK did not change significantly, and its output decreased by 0.5%.

Ameridial and recrystallization is carried out in the conditions of example 1. The result: quality PMDA on the content of the main product of 99.9%, the total yield of 88,2%.

Example 10 (comparative). The experience is conducted under the conditions of example 9 with the only difference that the ratio Br:F changed from 1:0.05 to 1:0,2, i.e. the content of F with respect to Br increased in 4 times. The contents of the PMC in the products of oxidation decreased with 97,5 to 95.4 percent.

Ameridial and recrystallization is carried out in the conditions of example 1. The result: quality PMDA content based the aqueous substance 99.89 per cent, the total yield of 86.1%.

Example 11 (comparative). The experience is conducted under the conditions of example 1 with the only difference that as a halide compound use only HBr, i.e. do not use Cl. Output PMK slightly decreased from 93.4 to 90.8%, the content of by-products (TMK and TMSC) increased from 0.38 to 0.85%, the content of PMC products of oxidation decreased with 98,0 to 96.8 per cent.

Ameridial and recrystallization is carried out in the conditions of example 1, with the only difference that when recrystallization as solvent is benzene, which is also not significantly reduce the content of individual organic impurities in the final product, in particular 4.5 to dicarboximide. The result: quality PMDA 99,5%; total yield of 84.3%.

Example 12 (comparative). The experience is conducted under the conditions of example 1 with the only difference that the temperature in degrees decreased from 205°→195°C→180°→165°s, respectively. The quality of the product has deteriorated significantly in content PMK with 98.0 to 90.2%, output fell by 4.2,%. Quality PMDA 99,77; total output to 82.1%.

Example 13 (comparative). The experience is conducted under the conditions of example 1 with the only difference that the pressure in each stage, reduce and cook until equilibrium corresponding to the vapor pressure of the reaction mass at each step at the respective temperatures: 165°→180°→195°→205�B0; S, which corresponds to the pressure (MPa): 0,15→0,17→0,19→0,2. In these conditions, the yield decreased by 5.3%, and the quality of the product (MCP) deteriorated over the content of the basic substance in the products of oxidation and amounted to 92.1%. Quality PMDA 99,79%; output to 82.3%.

Example 14 (comparative). The experience is conducted under the conditions of example 1 with the only difference that the reaction time at each step is reduced so that the total time of the oxidation reaction was 60 minutes. Output decreased to 80%, product quality has deteriorated significantly, the content of the basic substance was 78.3%. Quality PMDA 99,77%, the yield of 80.3%.

Example 15. (comparative). The experience is conducted under the conditions of example 1 with the only difference that the composition of the catalyst excluded Zn, Cl and F. the Output decreased from 93.4 to 88.8%, as the product of oxidation on the content of the basic substance decreased from 98 to 90.8%, the number of products increased from 0.38 to 1.92%, i.e. in 5 times. Quality PMDA of 99.75%; the yield of 79.8%.

Example 16. The experience is conducted under the conditions of example 1 with the only difference that the temperature in degrees of oxidation increased by 15°i.e. 180°→195°→205°→220°s, respectively. Under these conditions, the product quality has improved in content PMK in the product by 0.6, and the output decreased by 0.8%. Quality PMDA 99,92%, the yield of 87.6%.

Example 17. The experience is conducted under the conditions of example 1 with the only difference that the temp is the temperature in degrees of oxidation was reduced by 25° With, i.e. 140°→155°→170°→180°s, respectively. The quality of the product has deteriorated significantly in content PMK and amounted to 96.9%, [TMK+TSK]=0,98%, the yield decreased to 92,0%. Quality PMDA of 99.85%, 87.3%.

Example 18 (prototype). The conditions of the experiment correspond to the prototype of the oxidation of durene. The basic substance content in the product amounted to 85.4 percent, including [TMK+TSK]=3,6%.

The result on the stage of ameridial: quality PMDA 96,1%, [PMK] of 1.6%, [organic matter] of 1.8%.

Low quality product at the stage of oxidation due to the inefficiency of the regime of oxidation in two stages, the composition of the catalyst and introduced additives promoter in the form of Hydrobromic acid in a mixture with aliphatic compounds selected from the group: methyl ethyl ketone, pentane-hexane fraction and the other in the amount of 4,8-82.3% of the mass of oxidizable hydrocarbon, which complicates the basic process of oxidation of durene and not provide the desired product of high purity.

Thus, the obtained data show that, compared with the prototype of the invention allows for more selective conducting phase oxidation of durene to pyromellitic acid and the stage of purification by recrystallization in a mixture of solvents to increase the output of PMDA and improve its quality.

92,0
Table 1

Conditions and results of oxidation of durene to PMC
No. of experimentsRatioTemperature (° (C) in degreesPressure (MPa) speedThe oxidation time (min) speedQuality PMK after IV stageThe output of the PMC,%
(Co+Mn)/ZnBr/ClBr/F123412341234[TMK+TSK],%PMC,%
11/0,101/0,3-1651801952052,62,42,22,0352520200,3898,05for 93.4
21/0,051/0,3-1651801952052,62,42,22,0302720200,4598,0
3 (Wed)1/0,301/0,3-1651801952052,62,42,22,0252520360,9996,189,2
41/0,101/0,15-1651801952052,62,42,22,0302720200,7297,093,0
51/0,101/0,151/0,11651801952052,62,42,22,0302720200,4897,994,1
61/0,101/0,5-1651801952052,62,42,22,0302720200,4996,9of 92.7
7 (Wed)1/0,101/2-/td> 1651801952052,62,42,01,830272020to 2.5780,484,0
81/0,10-1/0,11651801952052,62,42,22,0302720200,57of 97.893,3
91/0,10-1/0,051651801952052,62,42,02,0302720200,4997,592,3
10 (Wed)1/0,10-1/0,21651801952052,62,42,01,8302720200,9095,4to 92.1
11 (Wed)1/0,101/-1/-1651801952052,42,22,0302720180,8596,890,8
12 (Wed)1/0,101/0,3-2051951801652,62,42,22,0302720201,0990,289,2
13 (Wed)1/0,101/0,3-1651801952051,51,71,92,0302720201,23to 92.1at 88.1
14 (Wed)1/0,101/0,3-1651801952052,62,42,01,8201614101,85to 78.380,0
15 (Wed)1/-1/--1651801952052,62,42,01,830 2720181,9290,8and 88.8
161/0,101/0,30-1801952102202,62,42,22,0302720200,3698,6592,6
171/0,101/0,30-1401551701852,22,01,81,6302720200,9896,992,0
18 prototype1/0,061/0,03-180220--3,03,0--60120--3,6085,480,3

Table 2

The results of ameridial and cleaning PMDA
no PPStage ameridialStage recrystallization
Quality

PMD, %
Sod. PMC, %Sod. org. approx., %Quality of PMDA, %T square, °CC, mg KOH/gContent. PMC, %The output PMD, %Metal cat-RA %
1789101112131415
199,230,450,3299.91 per286,410310,02at 88.1UTS.
299,180,430,3999,90286,310300,0387,7UTS.
3 (Wed)99,100,420,48of 99.97285,410250,0485,9UTS.
499,210,440,3599,90286,410300,0387,9UTS.
599,240,440,3099.91 per286,410310,3388,5UTS.
699,180,43 0,3999,90285,710300,0387,9UTS.
7 (Wed)98,70,420,8899,85285,110250,0473,2UTS.
899,240,440,3299,40285,310230,3485,6UTS.
999,260,430,3799,9286,110240,0488,2UTS.
10 (Wed)99,210,420,3299.89 per285,110230,0586,1UTS.
11 (cp)99,250,340,4299,50285,110220,2484,3UTS.
12 (cp)99,080,420,3099,82286,010230,682,1UTS.
13 (cp)99,020,350,7399,79285,810210,0682,3 UTS.
14 (cp)the 98.90,370,7299,77285,710210,0680,3UTS.
15 (cp)of 98.20,390,79of 99.75285,410210,0779,8UTS.
1699,240,440,3099,92286,010310,0287,6UTS.
1799,100,420,4899,85285,510270,05of 87.3UTS.
18 (prototype)96,100,821,80------

The method of obtaining an intramolecular dianhydride pyromellitic acid by sequential oxidation of durene to pyromellitic acid with oxygen in an acetic acid medium at elevated temperature and pressure in the presence of salts of heavy metals and halide compounds, in particular bromine, entered dispersed at each stage, thermal americasales oxidation products in pseudocumene and following the cleaning by hot filtration of the resulting solution and crystallization, characterized in that as a halide compounds used kaleidotrope acid Ledger number HBr, HCl, HF in the form of binary or ternary mixtures (HBr+HCl), (HBr+HF), (HBr+HCl+HF) ratio Br:Cl:F, equal 1:(0,15-1,0):(0,01-0,5) and/or HBr, and as the metal catalyst MK - salts of Mn, Co, Zn in the form of acetates, bromides, chlorides or fluorides in the ratio of metal ions (Co+Mn:Zn = 1:(0.05 to 0.1), respectively, with a total value MK:SC=1:(1,2-3), and the oxidation is carried out in 4 steps in the temperature range 140-220°and a pressure of 2.0 to 3.0 MPa so that the temperature at each step increase by 10-15°and the pressure reduced to 0.2-0.3 MPa to excess pressure on the 4th level, exceeding the vapor pressure of the reaction mass not less than 0.25 MPa, and the reaction time at each step within 20-60 min, and cleanup PMDA carried out by recrystallization in a mixed solvent consisting of benzene and ethyl acetate.



 

Same patents:

FIELD: organic chemistry, chemical technology.

SUBSTANCE: invention relates to an improved method for synthesis of halogenphthalic acid. Method involves mixing from 3 to 7 weight parts of acetic acid with 1 weight part of halogen-ortho-xylene, with from 0.25 to 2 mole% of cobalt source as measured for above said halogen-ortho-xylene, with from 0.1 to 1 mole% of manganese source measured for above said halogen-ortho-xylene, with from 0.01 to 0.1 mole% of metal source as measured for above said halogen-ortho-xylene wherein this metal is chosen from zirconium, hafnium and their mixtures, with from 0.02 to 0.1 mole% of bromide source as measured for above said halogen-ortho-xylene wherein halogen-ortho-xylene is represented by the formula (IV): wherein X represents halogen atom. Method involves holding the reaction mixture under pressure 1600 KPa, not less. At temperature 130-2000C, addition of molecular oxygen-containing gas to the reaction mixture in consumption 0.5 normal m3 of gas/h per kg of halogen-ortho-xylene in the reaction mixture for time sufficient for 90% conversion of halogen-ortho-xylene to yield halogenphthalic acid. Also, invention relates to a method for synthesis of halogenphthalic anhydride by distillation and dehydration of halogenphthalic acid, and to a method for synthesis of polyesterimide that involves interaction of halogenphthalic anhydride with 1,3-diaminobenzene to yield bis-(halogenphthalimide) of the formula (II): wherein X means halogen atom, and interaction of bis-(halogenphthalimide) of the formula (II) with alkaline metal salts of dihydroxy-substituted aromatic hydrocarbon of the formula (IV): OH-A2-OH wherein A2 means a bivalent radical of aromatic hydrocarbon to yield polyesterimide.

EFFECT: improved method of synthesis.

20 cl, 2 tbl, 5 ex

FIELD: chemical technology.

SUBSTANCE: invention relates to an improved method for preparing o-xylene-air mixture used in synthesis of phthalic anhydride. Method involves complete evaporation of o-xylene in vaporizer in the absence of oxygen. Then vapor is superheated in superheater to prevent its condensation followed by mixing with technological air, and this mixture is fed into reactor for synthesis of phthalic anhydride. Method provides the charge value of the parent reaction mixture by o-xylene in the limits from 80 g of o-xylene per 1 nm3 of air to 120 g of o-xylene to 1 nm3 of air.

EFFECT: improved method for preparing mixtures, increased yield of end product.

5 cl, 3 dwg, 1 ex

FIELD: organic chemistry, chemical technology.

SUBSTANCE: invention relates to the improved method for preparing phthalic anhydride from vat waste resin in manufacture of phthalic anhydride. Method involves treatment of vat waste resin in manufacture of phthalic anhydride with dimethylformamide at stirring at temperature 60-70°C and isolation of phthalic anhydride. Resin is a toxic waste in manufacture. Using a solvent under optimal conditions in resin treatment provides the wasteless manufacture and value product - phthalic acid is recovered. Phthalic acid is used in synthesis of pigment, phthalocyanine.

EFFECT: improved preparing method.

1 ex

The invention relates to the field of anhydrides of carboxylic acids, in particular, to methods selection of phthalic anhydride from a mixture flowstone

The invention relates to the production of ortho-substituted benzoldicarbonic acids and their intramolecular anhydrides, in particular trimellitic acid and its anhydride, which find wide application in the manufacture of polymeric materials: high quality plasticizers, high temperature polyamidoamine coatings, insulating varnishes

The invention relates to the chemical industry, to technology utilization of solid industrial waste, in particular waste of phthalic anhydride

The invention relates to a method of separation of phthalic anhydride from a mixture flowstone

The invention relates to the chemical industry and can be used in the production of plasticizers in polymers processing

The invention relates to a method of allocating dianhydride pyromellitic acid from high-temperature gas containing vapours, in particular from high-temperature gas contact formed by vapor-phase oxidation of durene

The invention relates to novim retinoid compounds of General formula I, II, III, IV with retinoid negative hormone biological activity and/or activity of antagonist retinoids, compositions based on them, a method of determining the retinoid antagonists hormones,the method of treating a pathological state in a mammal, vospriimchivosti to treatment with retinoid antagonist or negative hormone by injection of compound I or II

The invention relates to new triazinyl compounds of formulas Ia and Ib:

< / BR>
or their salts, where in the formula Ia W represents N or C-CO-R, where R denotes HE OC1-C6alkyl or NR3R4where R3and R4- N or C1-C6alkyl, or formula Ib Az denotes imidazopyridine and in both formulas Ia and Ib R1represents C1-C4alkyl, R2denotes phenyl fragment or 2,5-cyclohexadiene-3,4-ridin-1 silt fragment
The invention relates to the selection of 2.5-biphenyldicarboxylic acids from oxidation products of 2,5-dimethylbiphenyl

The invention relates to a method for producing monomer, in particular 2,5-biphenyldicarboxylic (filteredfiles) acid, which can be used together with other aromatic acids and dialami for the production of thermotropic liquid crystal polyesters (TGCP) industrial

FIELD: process for continuous production of terephthalic or isophthalic acid by liquid phase oxidation of respective aromatic dialkyl hydrocarbon.

SUBSTANCE: in order to prepare reaction solvent at least part of mother liquor separated from produced acid is used. Oxidation catalyst concentration in mother liquor is measured beforehand and then oxidation catalyst concentration is continuously corrected due to direct control (regardless of water content). Predetermined quantities of solvent and aromatic hydrocarbon as raw material are continuously supplied to oxidizing reactor for oxidizing aromatic hydrocarbon by means of molecular oxygen. Water concentration in condensate returned from reactor is measured and controlled by means of discharged quantity of returned condensate for stabilizing water concentration in reaction system in order to obtain in the result dicarboxylic acid. Oxidation temperature is sustained stable due to controlling pressure; oxygen concentration in exhaust gas is sustained stable due to controlling feed of oxygen containing gas.

EFFECT: production of stable quality acid, rational consumption of resources, power and water for performing process.

FIELD: organic chemistry, chemical technology.

SUBSTANCE: invention relates to an improved method for synthesis of halogenphthalic acid. Method involves mixing from 3 to 7 weight parts of acetic acid with 1 weight part of halogen-ortho-xylene, with from 0.25 to 2 mole% of cobalt source as measured for above said halogen-ortho-xylene, with from 0.1 to 1 mole% of manganese source measured for above said halogen-ortho-xylene, with from 0.01 to 0.1 mole% of metal source as measured for above said halogen-ortho-xylene wherein this metal is chosen from zirconium, hafnium and their mixtures, with from 0.02 to 0.1 mole% of bromide source as measured for above said halogen-ortho-xylene wherein halogen-ortho-xylene is represented by the formula (IV): wherein X represents halogen atom. Method involves holding the reaction mixture under pressure 1600 KPa, not less. At temperature 130-2000C, addition of molecular oxygen-containing gas to the reaction mixture in consumption 0.5 normal m3 of gas/h per kg of halogen-ortho-xylene in the reaction mixture for time sufficient for 90% conversion of halogen-ortho-xylene to yield halogenphthalic acid. Also, invention relates to a method for synthesis of halogenphthalic anhydride by distillation and dehydration of halogenphthalic acid, and to a method for synthesis of polyesterimide that involves interaction of halogenphthalic anhydride with 1,3-diaminobenzene to yield bis-(halogenphthalimide) of the formula (II): wherein X means halogen atom, and interaction of bis-(halogenphthalimide) of the formula (II) with alkaline metal salts of dihydroxy-substituted aromatic hydrocarbon of the formula (IV): OH-A2-OH wherein A2 means a bivalent radical of aromatic hydrocarbon to yield polyesterimide.

EFFECT: improved method of synthesis.

20 cl, 2 tbl, 5 ex

FIELD: chemical industry; petrochemical industry; methods of extraction of the unreacted xylene from the acetic acid at production of the terephthalic or isophthalic acid.

SUBSTANCE: the invention is pertaining to the field of production of the terephthalic or isophthalic acid by oxidation of the corresponding alkyl benzene, in particular, to the stage of separation of the reaction mixture including the acetic acid in the capacity of the dissolvent. The method is intended for extraction of the unreacted para-xylene or meta-xylene at the regeneration of the acetic acid using isobutyl acetate as the azeotropic agent for dehydration of the acetic acid. From the azeotropic distillation column at the temperature of 94-100°С separate the fraction containing the para-xylene or meta-xylene, which is fed into the run-down tank, where separate the aqueous phase from the organic phase. In the azeotropic section of the azeotropic distillation column determine the ratio of the para-xylene or meta-xylene and the isobutyl acetate in the stored fraction of the organic phase and periodically remove the accumulated part of the organic phase until the mass ratio of the concentrations of the para-xylene or meta-xylene and the azeotropic agent attains the interval from 0.5 up to 6. As the version of realization of the method route the circulation of the part of the accumulated fraction of the organic phase from the run-down tank to the azeotropic column. The technical result of the invention is upgrade of the production process of regeneration of the acetic acid and the unreacted alkylbenzene using the phase of the azeotropic distillation of xylenes from the acetic acid.

EFFECT: the invention ensures the upgrade of the production process of regeneration of the acetic acid and the unreacted alkylbenzene using the phase of the azeotropic distillation of xylenes from the acetic acid.

8 cl, 4 tbl, 5 dwg

FIELD: method and composition for selective removal of iron solvent oxide from surface of titanium parts without damaging them.

SUBSTANCE: method comprises steps of adding to distillation tower organic acid such as alkyl mono-carboxylic acid having 2 - 6 C atoms or benzoic acid or their mixture at first temperature range 30 -125°C; passing said organic acid through distillation tower at absence of molecular oxygen; adding to organic acid of first temperature and without molecular oxygen aqueous solution of hydro-halide acid whose temperature is less that said first temperature for preparing aqueous solution of solvent composition at second temperature that is less than first temperature; providing contact of titanium part and solvent composition in distillation tower at absence of molecular oxygen.

EFFECT: possibility for selective removal of iron oxide from surface of titanium parts without damage of said parts.

18 cl, 1 dwg, 6 tbl, 14 ex

FIELD: chemical industry; methods of production of the purified crystalline terephthalic acid.

SUBSTANCE: the invention is pertaining to the improved method of production and separation of the crystalline terephthalic acid containing less than 150 mass ppm of the p-toluene acid in terms of the mass of the terephthalic acid. The method provides for the following stages: (1) loading of (i) para- xylene, (ii) the water reactionary acetic-acidic medium containing the resolved in it components of the oxidation catalyst, and (iii) the gas containing oxygen fed under pressure in the first zone of oxidation, in which the liquid-phase exothermal oxidization of the para-xylene takes place, in which the temperature and the pressure inside the first being under pressure reactor of the oxidization are maintained at from 150°С up to 180°С and from 3.5 up to 13 absolute bars; (2) removal from the reactor upper part of the steam containing the evaporated reactionary acetic-acidic medium and the gas depleted by the oxygen including carbon dioxide, the inertial components and less than 9 volumetric percents of oxygen in terms of the non-condensable components of the steam; (3) removal from the lower part of the first reactor of the oxidized product including (i) the solid and dissolved terephthalic acid and (ii) the products of the non-complete oxidation and (ii) the water reactionary acetic-acidic medium containing the dissolved oxidation catalyst; (4) loading of (i) the oxidized product from the stage (3) and (ii) the gas containing oxygen, into the second being under pressure zone of the oxidation in which the liquid-phase exothermal oxidization of the products of the non-complete oxidization takes place; at that the temperature and the pressure in the second being under pressure reactor of the oxidization are maintained from 185°С up to 230°С and from 4.5 up to 18.3 absolute bar; (5) removal from the upper part of the second steam reactor containing the evaporated water reactionary acetic-acidic medium and gas depleted by the oxygen, including carbon dioxide, the inertial components and less, than 5 volumetric percents of oxygen in terms of the non-condensable components of the steam; (6) removal from the lower part of the second reactor of the second oxidized product including (i) the solid and dissolved terephthalic acid and the products of the non-complete oxidation and (ii) the water reactionary acetic-acidic medium containing the dissolved oxidation catalyst; (7) separation of the terephthalic acid from (ii) the water reactionary acetic-acidic medium of the stage (6) for production the terephthalic acid containing less than 900 mass ppm of 4- carboxybenzaldehyde and the p-toluene acid; (8) dissolution of the terephthalic acid gained at the stage (7) in the water for formation of the solution containing from 10 up to 35 mass % of the dissolved terephthalic acid containing less than 900 mass ppm of the 4- carboxybenzaldehyde and the p-toluene acid in respect to the mass of the present terephthalic acid at the temperature from 260°С up to 320°С and the pressure sufficient for maintaining the solution in the liquid phase and introduction of the solution in contact with hydrogen at presence of the catalytic agent of hydrogenation with production of the solution of the hydrogenated product; (9) loading of the solution of the stage (8) into the crystallization zone including the set of the connected in series crystallizers, in which the solution is subjected to the evaporating cooling with the controlled velocity using the significant drop of the temperature and the pressure for initiation of the crystallization process of the terephthalic acid, at the pressure of the solution in the end of the zone of the crystallization is atmospheric or below; (10) conduct condensation of the dissolvent evaporated from the crystallizers and guide the condensed dissolvent back into the zone of the crystallization by feeding the part of the condensed dissolvent in the line of removal of the product of the crystallizer, from which the dissolvent is removed in the form of the vapor; and (11) conduct separation of the solid crystalline terephthalic acid containing less than 150 mass ppm of the p-toluene acid in terms of the mass of the terephthalic acid by separation of the solid material from the liquid under the atmospheric pressure. The method allows to obtain the target product in the improved crystalline form.

EFFECT: the invention ensures production of the target product in the improved crystalline form.

8 cl, 3 tbl, 2 dwg, 3 ex

FIELD: organic chemistry, chemical technology.

SUBSTANCE: invention relates to the improved method for preparing dimethyl-1,5-naphthalene dicarboxylate that is used in preparing polymers based on thereof and articles made of these polymers. The economic and effective method involves the following stages: (1) dehydrogenation of 1,5-dimethyltetraline to yield 1,5-dimethylnaphthalene; (2) oxidation of 1,5-dimethylnaphthalene prepared at dehydrogenation stage to yield 1,5-naphthalene dicarboxylic acid being without accompanying isomerization stage, and (3) esterification of 1,5-naphthalene dicarboxylic acid prepared at oxidation stage in the presence of methanol to yield the final dimethyl-1,5-naphthalene dicarboxylate.

EFFECT: improved preparing method.

9 cl, 3 dwg, 5 ex

FIELD: organic chemistry, chemical technology.

SUBSTANCE: invention elates to a method for preparing pure isophthalic acid. Method involves step-by-step oxidation of m-xylene with oxygen-containing gas in acetic acid medium in the presence of catalyst comprising heavy metal salts and halide compounds under increased pressure and temperature up to the definite degree of conversion of m-xylene to isophthalic acid and the following isolation of the end product. Oxidation of m-xylene is carried out for tree steps at discrete change of temperature by steps to side of decreasing and with the following increasing, or increasing with the following decreasing by the schedule: T1 > T2 < T3 or T1 < T2 > T3 in the temperature range 180-200°C in the presence of manganese-cobalt-bromide catalyst modified with additives of zinc and/or nickel salts in the following ratio of metals Mn : Co : Ni = 1:(0.5-2):(0.005-0.01):(0.005-0.01), respectively, in the total concentration of metals 490 p. p. m. in the reaction mass in the equimolar ratio of the amount of bromine with respect to metals and mixing time of reagents added to the reagents zone <10 s. Then oxidized compound from the 3-d step is subjected for cooling, crystalline isophthalic acid is isolated and treated successively by washing out with acetic acid at temperature 80-100°C in the mass ratio isophthalic acid : CH3COOH = 1:(2-2.5) to remove catalyst and with water at increased temperature 150-230°C in the ratio isophthalic acid : water = 1:(2-3) to remove acetic acid. Then the washed out product is isolated and dried by known procedures to obtain highly pure isophthalic acid. Method provides simplifying the process and to improve quality of isophthalic acid.

EFFECT: improved preparing method.

2 tbl, 1 dwg, 10 ex

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