RU2626005C1 - Method for producing bisphenols - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: process comprises reacting phenol or its derivatives with a ketone or aldehyde at a temperature of 30-80°C in presence of a catalyst and hydrogen sulfide promoter. The cation-exchange resin is used as the catalyst, and hydrogen sulfide is fed at a pressure of 0.1-1.0 MPa, at a molar ratio of ketone or aldehyde: phenol or its derivatives: hydrogen sulphide 1: (2-10):(0.12-0.7).

EFFECT: method allows to produce high-quality bisphenols with main substance content of not less than 99,9 percent in high yield.

3 cl, 1 tbl, 2 ex

Description

The invention relates to organic chemistry, and in particular to the field of synthesis of bisphenols (Bisphenol, hereinafter referred to as BP). Bisphenols are the key monomers that are used in the manufacture of epoxy resins, as well as polycarbonates - linear polyesters of carbonic acid. Depending on the type of source BP, they have different physicochemical properties and are used in almost all industries, including aviation and space.

Various methods for producing BP are currently known. For example, a method is described [Pat. USA 2884462, IPC С07С 37/14, С07С 43/205; publ. 04/06/60], including the interaction of phenol with an aliphatic unsaturated compound in the presence of a catalyst — Lewis acid (for example, boron fluoride, aluminum trichloride) or sulfuric acid.

There is also known a method [Pat. U.S. 4814520, IPC B01J 27/00, B01J 27/10, C07B 61/00; publ. 03/21/89] conducting interactions in the presence of hydrochloric acid.

Industrial application has been obtained for the synthesis of BP by condensation of phenol or its derivatives with a ketone or aldehyde in the presence of acid catalysts (for example, strong mineral acids) and a promoter - compounds containing a sulfur atom with a valency of ≤2 (for example, mercaptans, sulfonyl chloride, thiosulfates, thiophenols, hydrogen sulfide )

It was found that the use of sulfur (divalent sulfur) compounds increases the reaction rate by several times.

The mechanism of action of sulfur compounds is their interaction with acetone carbocation in the presence of an acid catalyst with the formation of half mercaptetals, which upon cleavage give an extremely active new carbcation (much more active than acetone carbcation). Sulfur carbathion further interacts with phenol, and with high speed.

This reaction in general form for the first homologous series - bisphenol A (hereinafter - BPA) is as follows:

In addition, by this reaction it is possible to obtain compounds having several different functional groups, which significantly expands the range of applications of the synthesized compounds.

For example, it is known [Pat. USA 5969180, IPC B01J 1/10, С07B 61/00, С07С 51/353, publ. 10.19.99] the use of levulinic acid as a ketone, which ensures the presence of acid groups in the final product.

Thus, the main reaction for producing BP is the condensation of phenols with ketones and aldehydes. This method is implemented in industry, however, attempts are still being made to improve it. The main areas are: selection of catalyst, promoter and optimization of process parameters.

Due to the high corrosive activity of mineral acids and the formation of a large amount of non-utilizable acid waste, at present, almost the entire industry has switched to BP using heterogeneous catalysts, which are mainly strongly acidic ion-exchange resins [Pat. RF 2373994, IPC B01J 31/10, B01J 37/00, B01J 37/10, publ. 11.27.09] modified with various sulfur compounds capable of ionizing in water [US Pat. USA 6534686, IPC С07С 37/20, publ. 03/18/2003]. This is due to the fact that this type of catalyst allows eliminating highly aggressive components of homogeneous catalysts from the process and conducting the reaction in continuous equipment.

However, this group of catalysts also has significant drawbacks in comparison, for example, with the hydrochloric acid – hydrogen chloride – hydrogen sulfide system. None of the known catalysts allowed to achieve simultaneously high reaction rates, selectivity, degree of conversion of reactants and purity of the target product. The main problem is that when using a catalytic system: a heterogeneous acid catalyst - a promoter, the latter is washed out of the reaction medium, as a result of which the selectivity of the process sharply decreases and the final product is contaminated with sulfur-containing compounds.

Known methods for producing BP using the modification of the cation exchange resin, when the mercapto group is attached to sulfonate groups, thereby modifying the resin by partial neutralization of acid groups [Application US 2014051803, IPC C07C 39/16, C08G 64/06, C08L 69/00, publ. 02/20/14]. Despite the good stability of these resins, the problem of leaching mercapto groups remains relevant. One way to reduce catalyst degradation is to attach a promoter to the acid sites of the catalyst to form a covalent bond [US Pat. USA 4584416, IPC B01J 31/10, B01J 39/20, C07B 61/00, publ. 04/22/86].

Another approach to this problem is possible, namely the use as a promoter of compounds containing not only mercapto and amino, but also sulfonate groups, for example aminomercaptosulfonic acid [US Pat. USA 5939494, IPC B01J 31/02, B01J 31/10, B01J 31/40, publ. 08/17/99]. Known use as a promoter of hydrogen sulfide [US Pat. USA 6858758, IPC С07В 61/00, С07С 37/16, С07С 37/20, publ. 02.22.05].

Another example are the catalysts obtained using sultones [US Pat. USA 6133190, IPC B01J 31/10, С07С 37/20, publ. 17.10.00]. One of the methods for their preparation consists in treating a polystyrene resin containing halogen-alkyl groups with a solution of n-butyllithium and sultone in tetrahydrofuran, further adding thioacetate to the resin to open the sultone ring and treating it with acid, as a result of which a radical is attached to the carbon skeleton of the polymer (see reaction schemes (2) and (3) containing both mercapto and sulfonate groups, for example:

However, none of the patents indicate the degree of conversion of the ketone, which casts doubt on the effectiveness of the catalysts mentioned above.

To obtain both a high degree of conversion of the starting components and a process selectivity, a necessary condition is a high acidity of the catalyst and a sufficient high concentration of the promoter, and these indicators must be constant during the synthesis.

A high degree of conversion of ketone (more than 90%) and selectivity (more than 90%) was achieved using hydrochloric acid or hydrogen chloride in addition to a sulfonate resin, fully or partially neutralized by mercaptoamines at atmospheric pressure and temperature from 40 to 100 ° C [Pat. USA 5914431, IPC B01J 31/08, С07В 61/00, С07С 37/20, publ. 06.22.99], as well as at elevated pressure from 0.07 to 0.1 MPa and a temperature from 20 to 70 ° C [Pat. U.S. 4317944, IPC C07C 37/20. publ. 03/02/82]. However, when implementing this method, problems again arise of neutralizing the reaction mixture, isolating the target product and corrosion of the equipment.

The closest technical solution is [Pat. US 7227046, IPC С07С 39/12, С07В 61/00, С07С 37/20, С07С 39/16, declared 01/08/2002, publ. 06/05/2007] a continuous method for producing BPA by the interaction of phenol and acetone in a molar ratio of 2: 1 to 50: 1 in the presence of a strongly acidic catalyst — a sulfonate resin (or hydrogen chloride) and a cocatalyst (promoter), in particular, a dithioether of formula R (R ¹ ) C (SR ² ) ₂ . where R and R ¹ = H, C ₁ -C ₁₂ straight or branched chain alkyl or phenyl, R ² = C ₁ -C ₁₂ straight or branched alkyl and a substituent carboxylic acid group.

The specified dithioether may be a derivative of methyl mercaptan. The contact time is 5-180 min at 25-180 ° C, which corresponds to a contact load on the catalyst for acetone of 0.3-12 ¹ / h, a pressure of 0.5-20 bar (0.05-2 MPa), the content of dithioether was 0 5-50 mol.% Of the amount of acid catalyst. The use of excess pressure allows you to maintain a constant concentration of sulfur promoter in the reaction mass, to eliminate losses and thereby significantly reduce its consumption.

At the end of the process, the excess pressure is released, while the vapor phase, which contains mainly dithioether and a certain amount of acetone and water, is returned back to the synthesis. Thereby, the maximum use of dithioether is achieved.

The disadvantages of this method of producing bisphenol are:

- rather complicated manufacture of dithioether catalysts: VMTP (2,2-bis (methylthio) propane) and VMTM (bis (methylthio) methane);

- rather complicated purification of the target bisphenol from impurities of sulfur-containing compounds having high boiling points of 155 ° C and 147 ° C, respectively.

The developers of the invention had the task of developing a new method for producing BP from phenol or its derivatives, by interacting with a ketone or aldehyde using an available catalyst and promoter, which would minimize the loss of the target product and obtain BP of various grades of high quality with high yield.

The essence of the invention lies in the fact that a method has been developed for producing BP from phenol or its derivatives by reacting with a ketone or aldehyde at a temperature of 30-80 ° C in the presence of a catalyst and a hydrogen sulfide promoter according to the present invention, a cation exchange resin is used as a catalyst, and hydrogen sulfide served under a pressure of 0.1-1.0 MPa, with a molar ratio of ketone: phenol: hydrogen sulfide 1: (2-10) :( 0.12-0.7). The contact load on the catalyst for ketone is 0.05-1.00 ¹ / h.

In this case, bisphenol A is obtained at a temperature of 30-50 ° C, and high molecular weight bisphenols - bisphenol Z, bisphenol C, bisphenol TMS, bisphenol FL - at a temperature of 50-80 ° C.

The method is carried out by supplying components in a molar ratio of ketone: phenol: hydrogen sulfide = 1: (2 ÷ 10) :( 0.12 ÷ 0.7).

As the resin used (sulfonic cation exchanger KU-2-8chS) of Russian production (GOST 20298-74, and as a promoter - gaseous hydrogen sulfide.

The technical result of the developed method for producing BP is to use a combination of the available KU-2-8hS catalyst and the hydrogen sulfide promoter (H ₂ S), obtained on an industrial scale, which allow at moderate temperatures of 30-80 ° C and pressure of 0.1-1.0 MPa to achieve a conversion of ketone of more than 90% and get high quality BP with a basic substance content of at least 99.9% with a high yield of up to 85-90%. In addition, under these conditions it is possible to obtain a wide range of BP of various brands.

The use of KU-2-8chS as a catalyst for producing BP is due to:

firstly, its high acidity due to the presence of active sulfo groups, high strength and resistance to destruction. This has a positive effect on the quality and yield of the target product;

secondly, KU-2-8chS is characterized by high osmotic stability, chemical resistance to aggressive reagents, durability, easily regenerated.

The use of hydrogen sulfide as a promoter is also due to several reasons:

- firstly, hydrogen sulfide effectively increases the reaction rate compared to some other sulfur-containing compounds (tert-butyl mercaptan, thiosulfate, sulfur monochloride, etc.);

- secondly, the selectivity of the process is one of the key factors in obtaining BP.

Although some studies have shown that mercaptans exhibit a higher catalytic activity than hydrogen sulfide, however, this activity increases only with a decrease in the length of the hydrocarbon radical.

For this reason, methyl mercaptan is attractive as a promoter, however, the advantage of hydrogen sulfide is fundamentally due to the low selectivity of the process, which determines the presence of impurities in the product, due to which coloring and further inhibition of polymerization occur, and this makes it difficult to use it in the production of polycarbonates.

An important point for achieving high selectivity is the creation of such conditions under which a high concentration of the promoter in the reaction mixture is maintained throughout the synthesis, which can be achieved by carrying out the process under pressure.

In addition, the problem of purification of the final product from the promoter itself, especially when using sulfur compounds, in the case of using hydrogen sulfide, is solved quite simply. At the end of the synthesis, when reducing pressure, almost all hydrogen sulfide (boiling point minus 60.3 ° C), when heated to 80 ° C, is removed from the reaction volume (residual content less than 0.1 wt.%).

Example 1 (comparative, prototype)

In a flowing metal reactor with a volume of 2.5 dm ³ , filled with 193 g of Amberlust® 15 strong acid solid catalyst (the remaining volume of the reactor is filled with an inert nozzle), equipped with a jacket, thermocouple and manometer, 58 g / h (1 mol / h) of acetone are continuously fed 940 g / h (10 mol / h) of phenol and 5 g / h (2.5% of the catalyst) BMTP (2,2-bis (methylthio) propane) or BMTM (bis (methylthio) methane). The reactor is hermetically sealed and heating is turned on to a temperature of 80 ° C. Due to the evaporation of the synthesis products, the pressure in the reactor increases to 0.3 MPa. The contact load on the catalyst for acetone is 0.3 ¹ / h. At the end of the synthesis, the mixture from the reactor is reduced, resulting in the formation of the crystalline adduct BPA - phenol, the light phase - BMTP or VMTM, which returns to the process and the heavy phase - phenol, which after regeneration returns to the synthesis. After isolation and purification, crystalline BPA is obtained.

Example 2

58 g / h (1 mol / h) of acetone and 940 g / h (10 mol / h) of phenol are fed into the reactor, filled with 580 g of KU-2-8hS sulfocationion according to Example 1. The reactor is sealed, heated to a temperature of 40 ° C and hydrogen sulfide is supplied from a cylinder under a pressure of 0.7 MPa, as a result of which, according to Henry's law, at this temperature, 17 g (0.5 mol) of H ₂ S are supplied. Contact load on the catalyst for acetone is 0.1 ¹ / h At the end of the synthesis, the mixture from the reactor is reduced, resulting in the formation of crystalline adduct BPA - phenol (with residual acetone and impurities) and the light phase - H ₂ S, which is returned to the process. In the adduct, gas chromatography determines the amount of acetone and BPA (conversion and selectivity), and after isolation, purification and analysis of BPA, the yield of the target product is determined. As a result, the following results were obtained: the conversion of acetone was 97.0%, the selectivity was 96.0%. The output of the BPA was 90.5%.

Other experiments are carried out similarly, examples and results of which are presented in the Table.

As follows from the Table, the BP yield of more than 85% with a ketone conversion of more than 90% with high selectivity of more than 86.0% is achieved when KU-2-8hC sulfocationionite is used as a catalyst in the range of 2-10 moles of phenol and 0.12-0, 7 moles of hydrogen sulfide per 1 mol of initial ketone, with acetone contact load of the catalyst 0.05-1.00 ¹ / h in the temperature range 30-50 ° C for low molecular weight BPA and 50-80 ° C for higher molecular weight bisphenols HRV, BPZ , VRTMS, BPFL, and in the pressure range of 0.1-1.0 MPa (see Table, items 2, 5, 7, 9, 11, 13, 15, 16-19). A decrease in the amount of phenol to 2 moles (the limiting value according to stoichiometry) and a decrease in the pressure of hydrogen sulfide are less than 0.1 MPa, which corresponds to a decrease in the amount of H ₂ S of less than 0.12 moles, leads to a decrease in all quantitative indicators (see the Table, p. 3, 6), and an excess of phenol of more than 10 moles and an increase in hydrogen sulfide pressure of more than 1.0 MPa, which corresponds to an increase in the amount of hydrogen sulfide more than 0.7 mol, a decrease in the contact load of less than 0.05 ¹ / h, no longer have a significant effect on the conversion, yield and selectivity of BP ( m. Table, pp 4, 8, 10). A lower temperature of less than 30 ° C and an increase in contact load of more than 1.00 ¹ / h lead to both a decrease in the conversion of ketone and a decrease in the yield of BP (see Table, items 12, 14). An increase in temperature above 80 ° C leads to a sharp decrease in the conversion of ketone and the yield of BP, and ultimately to the grinding of the reaction mass due to, apparently, an increase in the rate of side processes (not shown in the Table).

The differences between the developed method for producing BP based on ketones and phenols from the known method (see Table 1) is that a new combination of a heterogeneous catalyst is proposed: a promoter, and gaseous hydrogen sulfide under pressure is used as the latter, which allows to increase the solubility of the promoter in the reaction mass and ensure its constant high concentration and thereby achieve a high conversion of ketone (more than 90%) and a BP yield of more than 85%, and also improve the quality of the target product (selectivity of more than 90%).

In addition, the method is technologically advanced - the stage of separation of the promoter from the interaction products is simplified, and also allows to obtain, in addition to BPA, a wide range of other brands of bisphenols. Thus, the problem facing the authors has been solved - a new effective method for producing BP from available raw materials has been developed using an inexpensive catalyst that can minimize BP losses and produce a high quality product with high yield.

Claims (3)

1. A method of producing bisphenols, comprising reacting phenol or its derivatives with a ketone or aldehyde at a temperature of 30-80 ° C in the presence of a catalyst and a hydrogen sulfide promoter, characterized in that a cation exchange resin is used as a catalyst, and hydrogen sulfide is fed under a pressure of 0.1 -1.0 MPa, with a molar ratio of ketone or aldehyde: phenol or its derivatives: hydrogen sulfide 1: (2-10) :( 0.12-0.7). 2. The method according to p. 1, characterized in that the contact load on the catalyst for ketone or aldehyde is 0.05-1.00 ¹ / h 3. The method according to PP. 1 and 2, characterized in that bisphenol A is obtained at a temperature of 30-50 ° C, and high molecular weight bisphenols are obtained at a temperature of 50-80 ° C.