WO2014031019A1

WO2014031019A1 - Method of transforming by-products in the process of synthesis of bisphenol a

Info

Publication number: WO2014031019A1
Application number: PCT/PL2013/050004
Authority: WO
Inventors: Kamil Kulesza; Bogusław TKACZ; Wojciech Balcerowiak; Andrzej Krueger; Maria Majchrzak; Stanisław MATYJA; Teresa RDESIŃSKA-Ćwik; Przemysław BARTOSZEWICZ; Renata Fiszer; Alina Iwanejko; Henryk IWA; Ewa ZASZŁY-TURKO; Bogumiła FILIPIAK
Original assignee: Instytut Cieżkiej Syntezy Organicznej "Blachownia"
Priority date: 2012-08-23
Filing date: 2013-02-07
Publication date: 2014-02-27
Also published as: RU2015110072A; DE112013004111T8; PL219656B1; CN104703958A; PL400471A1; DE112013004111T5; BR112015003769A2; RU2620086C2

Abstract

A method of transforming by-products in the process of synthesis of bisphenol A characterized in that a solution of by-products and p,p'-BPA in phenol, containing not more than 18% of the p,p'-BPA isomer, not more than 0.5% of water and not less than 0.15 mol of the o,p'-BPA isomer per 1 mol of p,p'-BPA and at least 0.01 mol of trisphenols per 1 mol of p,p'-BPA is contacted at a temperature of at least 60°C and up to 80°C as well as at a volumetric and spatial flow rate of up to 2.0 m³/(rri³ _k∙h) with macroporous, sulphonic ion-exchange resin in the hydrogen form with bimodal ion structure, and the total volume of pores with a radius not greater than 20 nm in the resin is less than 0.5 ml/g, while the total volume of pores with a radius of 20 nm to 100 nm is greater than 0.8 ml/g.

Description

Method of transforming by-products in the process of synthesis of bisphenol A

This invention relates to the method of transforming by-products in the process of synthesis of bisphenol A, a monomer for producing polycarbonates used in the electronics, computing, optical, automotive, building industries and medicine as well as epoxy resins for producing protective coats, composites, paints and adhesives. Plastic materials based on bisphenol A (BPA) are used in consumer products such as mobile phones, computers, household appliances, bicycle helmets. Bisphenol A is also used for producing unsaturated polyester resins, polysulphonic resins and polyetherimides as well as additives for plastic materials, e.g. flame retardants and thermal stabilizers.

Bisphenol A is obtained by condensation reaction of a carbonyl compound - acetone and an aromatic hydroxyl compound, e.g. phenol, in the presence of acidic catalysts. The catalyst typically used for BPA synthesis is sulphonic polystyrene-divinylbenzene (PS- DVB) resin, optionally with the addition of a promoter (thiol compounds, e.g. 2,2- dimethyl-l,3-thiazolidine and 2-aminoethanethiol) which increases the yield and selectivity of the condensation reaction of phenol and acetone to bisphenol A and the isomerization reaction of by-products to bisphenol A. Other effective catalysts for the synthesis of bisphenol A, as described in the literature, include zeolites, metal oxides, polysiloxanes and acidic catalysts affixed to organic or inorganic support.

In the presence of acidic catalysts, reversible isomerization reactions of p,p '-BPA and o,p '-BPA as well as a reaction of trisphenol I and phenol takes place. The reaction of BPA synthesis occurs within a narrow temperature range at an optimally high molar ratio of phenol to acetone and during sufficient contact time. In addition to the main product - bisphenol - the reaction mixture contains an excess amount of phenol, catalyst, non- reacted acetone, water, different by-products such as a mixture of phenol isomers and derivatives, e.g. 2-(2-hydroxyphenyl)-2-(4-hydroxyphenyl)propane, so-called o,p '-BP A isomer, and 2,4-(4-hydroxycumyl)phenol (trisphenol I). Also, a cyclic dimer of PIPF -

1.1.3- trimethyl-3-(4-hydroxyphenyl)-5-indanol and a co-dimer of 4-(4-hydroxyphenyl)-

2.2.4- trimethylchroman are formed in substantial quantities. Isopropenylphenol trimers, jointly referred to as trisphenol II, are also undesirable products. By-products may accumulate in process streams which has an adverse impact on the product quality. The post-reaction mixture from BPA synthesis is distilled to remove non-reacted ingredients and water. At a high temperature, BPA degrades to phenol and isopropenylphenol which undergo further reactions and thus increase the percentage of by-products, including colour complexes of metals with phenols, which results in high colouration of the raw BPA. Methods for reducing the scale of formation of by-products, as known from patent descriptions, include e.g. an isomerization reaction of o,p '-BP Ά to p,p'-EPA (JP 08333290, EP 630878, JP 05271132, JP 05294872, EP 630878, WO 9708122, WO 0134544) which takes advantage of the fact that after crystallization of the BP A/phenol adduct, the concentration of the o,p '-BPA isomer is higher than the equilibrium concentration and the process of catalytic decomposition occurs under the influence of acidic (WO 0040531) or basic (PL 181992) catalysts. The formation of by-products, e.g. 2-(2-hydroxyphenyl)-2-(4- hydroxyphenyl)propane, can also be limited or partially eliminated by selecting appropriate process parameters and recycling post-crystallization liquors to successive synthesis stages (US 6858759, PL 199344, PL 210812). The greatest advantage regarding the limitation of formation of the o, ? '-BPA isomer consists in recycling the mother liquor to the first synthesis stage, and therefore the patent literature includes first of all embodiments consisting in recycling part of the mother liquor to successive synthesis stages as an optional possibility only, with no indication of the resulting advantages (US 6858759).

A method for reducing the degradation of BPA consists in neutralizing acidic impurities present in the post-reaction mixture by introducing neutralizing compounds (carbonates and alkali metal hydroxides), filtering the raw BPA through cation-exchange resin (Na, K, Li, Ca, Mg) or inorganic ion-exchangers (US 6512148). Under conditions of the process during which an isomerization reaction of o,p '-BPA to p,p '-BPA occurs, other reactions may take place which result in the formation of the p,p '-BP A isomer, more particularly the reaction of trisphenol I and phenol, as referred to in the EP 1 985 602 patent description.

During the transformation process there are also other undesirable reactions which lead to the formation of by-products, in that mostly reactions resulting in the formation of the cyclic dimer of 4-isopropenylphenol (Kulesza, K.; German, K. Modern Polym. Mater, for Env. Appi. ; Pielichowski, Ed. K., WNT TEZA, Cracow, 3 (2008), 93).

According to the patents no. JP 3312920, JP 62178532, JP 2011098301 the efficiency of the process of bisphenol A synthesis depends on the morphological structure of catalyst particles, first of all their diameter, porosity and oxidation resistance (total organic carbon, TOC). The structure of porous ion-exchange catalysts used as catalysts for producing bisphenol A in the form of quasi- spherical grains has an effect on the thermosensitivity and hydrophobicity of an ion-exchanger which allows determining the correlation between the effectiveness of ion-exchange catalysts and their average pore size in the swollen state. A method is known for describing the porous structure of ion-exchange catalysts in the swollen state by the complementary use of methods of thermoporometry of macroporous sulphonic cation exchangers as well as methods of speciation of sulphonic groups (Balcerowiak, W.; Kulesza, K. Przemysl Chemiczny 86/5 (2007) 382-385), however the correlation between the effectiveness of ion-exchange catalysts and their average pore size in the swollen state remains unknown.

The object of the invention was to improve the method of transformation of byproducts in the synthesis of bisphenol A towards the p,p '-BP A isomer as well as towards limitation of the quantity of the resulting undesirable by-products.

It has transpired unexpectedly that at a temperature below 65°C the desirable reaction of isomerization to the p,p '-BPA isomer clearly decelerates and at the same time reactions leading to the formation of by-products occur, while at a temperature above 80°C undesirable by-products starts prevailing in the process of transformation.

It has also transpired unexpectedly that good catalysts for the transformation of by- products include catalysts in which the total volume of pores with a radius not greater than 20 nm is less than 0.5 ml/g and the total volume of pores with a radius of 20 nm to 100 nm is greater than 0.8 ml/g.

The essence of the method according to the invention is characterized in that a solution of by-products and p,p '-BPA in phenol, containing not more than 18% of the p,p '- BPA isomer, not more than 0.5% of water and not less than 0.15 mol of the o,p '-BPA isomer per 1 mol of p,p '-BPA and at least 0.01 mol of trisphenols per 1 mol of p,p '-BPA is contacted at a temperature of at least 60°C and up to 80°C as well as at a volumetric and spatial flow rate of up to 2.0 m³/(m³k*h) with macroporous, sulphonic ion-exchange resin in the hydrogen form with bimodal ion structure, and the total volume of pores with a radius not greater than 20 nm in the resin is less than 0.5 ml/g, while the total volume of pores with a radius of 20 nm to 100 nm is greater than 0.8 ml/g.

Preferably, the transformation of by-products in the synthesis of p,p '-BPA is carried out at a temperature of 65-75°C.

Preferably, not more than 50% of the post-reaction solution is recycled in the process. Preferably, a catalyst containing 5.0-5.34 mmol of -SO₃H groups per 1 g of the dry weight of the catalyst is used in the process.

Preferably, the process is carried out with the use of a catalyst in the form of resin in which the total volume of pores with a radius of up to 20 nm is 0.4 - 0.49 ml/g and the total volume of pores with a radius of 20 nm to 100 nm is 1.0 - 1.5 ml/g. The transformation of by-products in the synthesis of p,p '-BP A is carried out by the method according to the invention at a temperature of 60-80°C, under atmospheric pressure, in a flow reactor with a fixed-bed catalyst in the form of macroporous, strongly acidic ion-exchange resin. The characteristics of polystyrene ion-exchange resin is determined by the method of speciation of sulphonic groups and by measuring the size of pores in the swollen state using the method of thermoporometry.

Examples 1-12

The process of transformation of by-products in the synthesis of p,p '-BP A is carried out in a flow reactor with a fixed-bed catalyst of 1.0 dm³. In the reactor, 1.0 dm³ of macroporous sulphonic resin with the following characteristics is mixed:

• ion-exchange capacity - 5.34 mol S03H/g^s (g^s - gram of the dry weight of the catalyst),

• volume of pores with a radius of up to 20 nm - 0.47 ml/g,

• volume of pores with a radius of 20 nm to 100 nm - 1.2 ml/g.

A solution of by-products in phenol is pumped through the catalyst bed while maintaining a temperature of 60-75°C. The flow of the liquid is regulated in the range of 0.6 m³/m³ _k*h and 1.8 rVmVh. The water content in the stream at the inlet to the reactor is 0.09%. Table 1 shows the results of the analysis of the process products. The post-reaction solution is divided into two streams, where the smaller stream (30% of the post-reaction solution) is heated in a flow heat exchanger up to the reaction temperature (60-75°C) and mixed in a static mixer with a fresh solution of by-products in the synthesis of p,p '-BPA in phenol at the inlet to the flow reactor. The larger stream containing 70% of the post-reaction solution from the ion-exchange reactor is a product of the transformation process.

Table 1 shows the basic parameters of the process and results of the transformation of by-products in the synthesis of p,p '-BP A.

0,6 1 50 1,72 0,16 0,06 0,32 14,4 23,8

2 65 1.50 0,12 0,07 0,54 25,4 42,8

3 70 1,40 0,10 0,08 0,65 30,3 52,4

4 75 1.37 0,10 0.12 0.66 31.9 52,4

1,2 5 60 1,83 0.17 0,05 0,20 9,0 19,0

6 65 1,51 0,15 0,06 0,52 24,9 28.6

7 70 1,39 0,12 0,07 0,65 30,8 42,9

8 75 1,38 0.12 0,10 0,64 31,3 42,9

1,8 9 60 1,89 0,18 0,05 0,12 6,0 14,3

10 65 1,56 0,16 0,05 0,46 22,4 23,8

11 70 1.47 0,15 0,06 0,57 26,9 28,6

12 75 1.40 0,15 0,08 0,60 30,3 28,6

A solution of the following by-products in phenol is fed into the reactor:

'-BPA isomer - 12.0%,

o,p '-BP A isomer - 2.01%,

trisphenols 1, II - 0.21%,

- cyclic dimer - 0.05 %,

- phenol - the remainder.

The data in Table 1 show clearly the slow progress of the reaction at a temperature of 60°C and an unexpectedly insignificant effect of the greater flow rate of the reaction solution through the catalyst bed with bimodal distribution of pore diameters on the deceleration of the isomerization reaction of o, ? '-BPA to p,p '-EPA at a flow rate in the range of 0.6 - 1.8 m³/(mVh). Comparative examples 13-16

The process of transformation of by-products in the synthesis of ρ,ρ'-BPA is carried out by the same method as described in examples 1-12, but at temperatures out of the range subject to patent claims or at flow rates out of the range subject to patent claims.

Table 2 shows the results of transformation of by-products in the synthesis of p,p '- BP A for examples 13-16.

Table 2. Results of transformation of by-products in the synthesis of p,p '-BP A

The data in Table 2 clearly show that:

• as soon as the temperature exceeds 80°C undesirable by-products starts prevailing in the process of transformation,

• a flow rate of more than 2 m³/(m³ _k*h) clearly decelerates the process, even though it is carried out in the preferable temperature range.

Claims

1. A method of transforming by-products in the process of synthesis of bisphenol A characterized in that a solution of by-products and p,p '-BPA in phenol, containing not more than 18% of the ρ,ρ '-ΕΡΚ isomer, not more than 0.5% of water and not less than 0.15 mol of the o, ? '-BPA isomer per 1 mol of p '-BPA and at least 0.01 mol of trisphenols per 1 mol of p,p '-BPA is contacted at a temperature of at least 60°C and up to 80°C as well as at a volumetric and spatial flow rate of up to 2.0 m³/(rriVh) with macroporous, sulphonic ion- exchange resin in the hydrogen form with bimodal ion structure, and the total volume of pores with a radius not greater than 20 nm in the resin is less than 0.5 ml/g, while the total volume of pores with a radius of 20 nm to 100 nm is greater than 0.8 ml/g.

2. A method according to claim 1 characterized in that the transformation of by-products in the synthesis of p,p '-BPA is carried out at a temperature of 65-75°C.

3. A method according to claim 1 characterized in that not more than 50% of the post- reaction solution is recycled in the process.

4. A method according to claim 1 characterized in that a catalyst containing 5.0-5.34 mmol of -SO₃H groups per 1 g of the dry weight of the catalyst is used in the process.

5. A method according to claim 1 characterized in that the process is carried out with the use of a catalyst in the form of resin in which the total volume of pores with

a radius of up to 20 nm is 0.4 - 0.49 ml/g and the total volume of pores with a radius of 20 nm to 100 nm is 1.0 - 1.5 ml/g.