EP3024809A1

EP3024809A1 - A method to obtain bisphenol a

Info

Publication number: EP3024809A1
Application number: EP14744653.8A
Authority: EP
Inventors: Maciej Kiedik; Antoni Marek KOREK; Anna Rzodeczko; Jerzy MRÓZ; Wieslaw Hreczuch; Adam Basta
Original assignee: Mexeo Wieslaw Hreczuch
Current assignee: Mexeo Wieslaw Hreczuch
Priority date: 2013-07-22
Filing date: 2014-07-02
Publication date: 2016-06-01
Also published as: WO2015012705A1; PL221981B1; PL404819A1

Abstract

The subject of the invention is a two- and three-step method to obtain Bisphenol A. Bisphenol A is obtained by condensing phenol with acetone in the presence of an acidic ion-exchange resin in which part of its sulfonic groups have been neutralized with 2,2-dimethyl-l,3-thiazolidine or cysteamine, in a single reactor which is divided into three reaction zones by filtration-slot nozzles whereupon Bisphenol A is separated from the resulting post-reaction mixture by way of one- or two-step suspension-crystallization, adduct decomposition and distilling-off of phenol. In an embodiment of the invention, the resulting Bisphenol A is subjected to falling-film fractional crystallization.

Description

A method to obtain Bisphenol A

This invention relates to a method to obtain Bisphenol A from phenol and acetone.

The patent No. US 5315042 discloses a continuous process to obtain Bisphenol A by contacting phenol with acetone in the presence of an acidic catalyst, at increased flow rates through the catalyst, the said flow rates being sufficient to reduce the conversion of acetone whereby the content of acetone is kept at a high level, leading to a high reaction rate and a corresponding increase in the yield of Bisphenol A. Owing to this, the residence time of Bisphenol A in the reaction zone is reduced and the content of byproducts affecting the coloration of Bisphenol A is reduced as well. The method has the disadvantage of consuming too much energy, which results from the low conversion of acetone and the corresponding low (10- 13%) increase in the concentration of Bisphenol A in the reaction, whereby the amount of unreacted raw materials for processing and regeneration per 1 ton of product is very high.

The Polish patent application No. P.381757 disclosed a method to obtain Bisphenol A from phenol and acetone in a reaction system comprising multiple steps, with inter-stage control of reaction temperature and control of water concentration before the final stage of the reaction system. The method provides a relatively low reaction selectivity of around 95% because the reaction is carried out without the presence of the 2,4-isomer of Bisphenol A or other by-products at a level which inhibits their formation in the reaction and, consequently, improves selectivity to at a minimum of 98%.

In the method disclosed in P.381757, an attempt to improve low selectivities is made by carrying out an isomerization step, where part of the stream of concentrated post-crystallization liquor, containing 2.21% of the 2,4-isomer of Bisphenol A and 0.71% of other by-products, is contacted with a macroporous, sulfonated ion-exchanger catalyst at temperatures in the range 328-353° K.

The isomerization as described above, cannot be effective because both the 2,4-isomer of Bisphenol A and the other by-products are present at a concentration much below their equilibrium level. Therefore, isomerization will not take place in that process and, consequently, it will not be possible to achieve selectivities above 95%, corresponding to a phenol unit consumption of as much as 868 kg/Mg BPA.

In the method described in that Patent, part of the stream of concentrated post-crystallization liquor is subjected to rectification with a simultaneous decomposition of phenol derivatives in the presence of KOH or NaOH - strong inorganic bases - at a temperature of at least 443° K.

It is generally known that catalytic decomposition of phenol derivatives - that is, mainly Bisphenol A and its 2,4-isomer - leads to the equimolar formation of phenol and 4-isopropenylphenol.

According to the method described in the said patent application, the phenol obtained in that step contained not more than 0.05% of isopropenylphenol (IPF), which expressly indicates that the IPF - a decomposition product and compound with a double bond, which is, therefore, susceptible to oligomerizatlon and polymerization - remains in the rectification column bottoms and is a waste product; this will obviously lead to extra losses and, consequently, cause a further increase in the unit consumption of phenol.

The method disclosed in P.381757 has another major drawback, namely, the very low increase in the concentration of Bisphenol A in the reaction, not higher than 10% according to the mass balance, which is good reason to expect high energy consumption in the process.

The Polish Patent No. PL 107987 describes a structure of a reactor for carrying out chemical reactions which are catalyzed by ion exchangers, specifically, exothermal reactions. The said reactor is in the form of a vertical cylinder-shaped column, equipped with filtering elements in the reactor in its bottom and top sections, which protect against the ion exchanger escaping from the reactor and is provided with a system of filtration-slot nozzles located in the reactor at a level between 1/3 and 2/3 of its total height and there is a partition below the said filtration-slot nozzles which is provided to reduce the reactor's cross-sectional area.

The International Patent Application No. WO/19302 describes a method to obtain Bisphenol A, according to which the reaction is carried out using a phenol-to- acetone ratio by mole from about 4 to about 12, in the presence of a modified ion- exchange resin catalyst in an essentially vertical, multistage suspension stripping apparatus. The entire phenol required for the reaction of condensation with acetone is fed to the tower-reactor at a point over the top plate. Part of the entire acetone required is fed to the plate below the top one and to some or all of the plates located at lower levels while an inert gas stream is made to flow upwards through a catalytic chamber, thus forming a liquid-solid suspension, to strip off any water from the reaction mixture. Technically, the method is highly complex and impracticable.

Patent PL 201330 describes a process carried out with the use of a double- zone catalytic bed, combined with post-reaction mixture take-off methods that are appropriate for such zones and with keeping appropriate values of water concentration and temperature in the catalytic bed, as well as with sufficient purification of the resulting product. Moreover, the process is characterized by low increase in Bisphenol A in the reaction, due to which the consumption of energy in the process is too high.

The European Patent No. 1809589 discloses a method in which preliminary conversion to obtain an increase in the concentration of Bisphenol A in the range 2- 15%, preferably 3-5%, is effected in the reactor in Step I whereas in Step II the reaction is carried out so that the difference in water concentrations between the reactor inlet and outlet in Step II is kept in the range 0.1-0.5%, preferably 0.1-0.2%, while the difference in acetone concentrations between the reactor inlet and outlet in Step II is kept at a maximum of 2%, preferably 1%, the difference between the concentrations of Bisphenol A between the inlet and outlet of that reactor is kept in the range 1-5%, preferably 1-2%, and the difference in temperatures between the reactor inlet and outlet in Step II is kept at a maximum of 15°C, preferably 5°C.

According to that method, part of reaction water is removed from the reaction mixture in condensation Step II in a continuous manner. The post-reaction mixture resulting from Step II, which contains not less than 15%, preferably not less than 23%, of Bisphenol A is made to flow to a distillation system to distill off a fraction that contains acetone, water and phenol, whereby crude Bisphenol A that contains not more than 5%, preferably not more than 1%, of phenol, is obtained as a residue. The crude Bisphenol A is separated by distillation or is made to flow to the melt fractional crystallization to obtain a visually pure Bisphenol A and a residue that contains Bisphenol A, its isomers and other byproducts. The post-reaction mixture from the condensation reaction Step II is optionally sent to the suspension- crystallization unit to obtain a crystalline Bisphenol A-phenol adduct in the form of a suspension which is then subjected to filtration or centrifugation to separate the adduct which is then sent to a distillation system in order to separate Bisphenol A.

In the known method as described above, after distilling off any water, the post-crystallization liquor is made to flow back to the reaction or to the distillation system for separation. The residue from separation by distillation or from the fractional crystallization is diluted with a stream of phenol and is subjected to a static crystallization to obtain a Bisphenol A-phenol adduct, which is made to flow to the distillation system together with the post-reaction mixture stream from the condensation reaction Step II. The residue after static crystallization is carried outside the process after distilling-off of phenol. The Step II reactors and, optionally, also the Step I reactors, are divided each into at least two reaction sections by at least three sets of slot nozzles which are located at various levels in the reactors. From one to six Step II reactors fall to every Step I reactor. The method of the invention enables a visually pure Bisphenol A to be obtained with selectivities up to 98%.

According to the method disclosed in the European Patent Application No. EP 2090562, Bisphenol A is obtained from phenol and acetone in the presence of acidic ion-exchange resin catalyst in two serially-connected reactors which are divided into reaction zones by filtration-injection nozzle sets, located at not less than three levels, in four steps. Steps I and II are effected in a first reactor in the series. In Step I, the reaction runs in the top zone of the first reactor with the reaction mixture flowing downwards, while Step II is effected in the bottom zone of the first reactor with the reaction mixture flowing upwards. Step III is effected in the top zone of a second reactor in the series, with the reaction mixture flowing downwards, to obtain an increase in the concentration of Bisphenol A by 1-10%, and Step IV runs in the bottom zone of the second reactor with the reaction mixture flowing upwards.

In the method disclosed in the International Patent Application No. PCT/PL2011/000010, a polycarbonate grade Bisphenol A is obtained from phenol and acetone in the presence of an acidic ion-exchange resin catalyst in a single reactor divided in three reaction zones (top zone I - middle zone II - bottom zone III) by means of filtration-injection nozzle sets located at not less than three levels, so that isomerization and rearrangement of by-products into Bisphenol A as well as phenol-acetone condensation take place in zone I while phenol-acetone condensation takes place in zones II and III.

From the resulting post-reaction mixture, Bisphenol A is separated by means of a one- or two-step suspension crystallization, filtration, or centrifugation of the Bisphenol A-phenol adduct, decomposition of the adduct and distilling-off of the phenol, while a fraction containing acetone, water and phenol is distilled from the post-crystallization mother liquor and separated into components, the dewatered mother liquor is made to flow back to the Bisphenol A synthesis, the distilled-off phenol and the other phenolic fractions are preferably admixed with an amount of acetone, preferably to obtain a concentration in the range 3-10%, and is contacted at a temperature in the range 50-87°C with the acidic ion-exchange resin in which part of its sulfonic groups have been neutralized with 2,2-dimethylthiazolidine or cysteamine and is made to flow to the suspension-crystallization step I or II.

The methods disclosed in the inventions referred to above, in the case where an ion-exchange resin catalyst is used with a chemically bound promoter of the reaction, have the common disadvantage of having its yield gradually reduced in the course of the process as the catalyst becomes deactivated layer by layer. Using the earlier-known solution of maintaining contact between the reaction mixture and the ion-exchange resin, in which the substituted promoter groups become deactivated, leads to a significant decrease in the reaction yield and selectivity and affects the purity and coloration of the final product.

This invention is intended to provide a method to obtain Bisphenol A using, as the catalyst, an ion-exchange resin in which part of its sulfonic groups have been neutralized with 2,2-dimethyl-l,3-thiazolidine or cysteamine so as to maintain a relatively constant efficiency of the reactor throughout its operation even though deactivation of part of the catalyst bed becomes intensified.

In the method according to the invention, Bisphenol A is obtained from phenol and acetone in the presence of a catalyst in the form of an acidic ion- exchange resin in which part of its sulfonic groups have been neutralized with 2,2- dimethyl-l,3-thiazolidine or cysteamine which function as the reaction promoter, in a single reactor which is divided into three reaction zones by filtration-slot nozzles, a portion of or the entire feed to the reaction mixture which contains phenol and 3- 6% acetone and reaction by-products is introduced at a temperature 50-75⁹C to top of the reactor and flows downwards through the catalyst, which is above the top nozzles.

Subsequently, part of or the entire post-reaction mixture is taken outside the reactor through its top nozzles as a final post-reaction mixture or - part of or the whole of it - is made to flow to a heat exchanger, where it is cooled down to a temperature 55-759C.

After cooling the post-reaction mixture, acetone is added thereto to obtain its concentration in the range 2-7% and the mixture is made to flow to the reactor via its middle or bottom nozzles to the reactor. Part of or the entire reaction mixture is made to flow downwards or upwards in the reactor and is taken out of the reactor as a final post-reaction mixture via the bottom or middle nozzles, respectively, while the remaining portion of the reaction mixture from the middle nozzles flows upwards and is taken out of the reactor via its top nozzles.

In the second step of operation of the reactor, the process is carried out in a different manner: a feed stream containing phenol and 3 - 6% acetone and the reaction by-products is introduced through the top or bottom nozzles.

The reaction mixture flows downwards or upwards, respectively, and is taken out of the reactor via its bottom and/or middle nozzles as a final post- reaction mixture.

In Step III of the reactor's operation, a feed mixture which contains phenol and 3 - 6% acetone and the reaction by-products is introduced via its middle nozzles, is made to flow downwards and is taken out of the reactor through its bottom nozzles as a final post-reaction mixture.

In another embodiment of the invention, the bottom section of the reactor is packed with beads 1-5 cm in diameter, up to a level of 20-60 cm above the bottom head of the reactor; this is intended to improve the effectiveness of the bottom filtration-slot nozzles.

In Steps II and III of the process as described above, a stream is fed to top of the reactor, which contains the reaction by-products, including the 2,4-isomer of Bisphenol A, 2,2-isomer of Bisphenol A, in an amount of not less than 1/20 of the feed stream to the reaction.

In one of the embodiments of this invention, the final post-reaction mixture in all periods of the reactor's operation, is contacted with an anion exchanger when leaving the reactor, whereupon is it is made to flow to an evaporator, where a fraction in the amount of 10-30% of the feed is distilled off which contains acetone, water and phenol. The residue from the evaporator is made to flow to the one- or two-step suspension-crystallization and to filtration or centrifugation; this produces a Bisphenol A-phenol adduct which is then made to flow to another evaporator to distill off the phenol, as a result of which a crude Bisphenol A, containing 0.5 - 3% of phenol, is obtained.

Any residual phenol is removed from the crude Bisphenol A by steam- stripping in the distillation column, whereby a final Bisphenol A product is obtained.

In another embodiment of the invention, Bisphenol A is separated from the obtained post-reaction mixture by distilling-off of acetone, water and phenol. The resulting Bisphenol A is subjected to the falling-film fractional crystallization to obtain a Bisphenol A which is characterized by high purity and improved thermal resistance.

According to yet another embodiment of the present invention, the streams which arise in the process and which contain Bisphenol A, isomers, trisphenols and other by-products, are contacted in the reactor with a macroporous ion-exchange resin at a temperature 55-852C which leads to the isomerization and rearrangement of by-products into Bisphenol A.

In yet another embodiment of the invention, the streams which arise in the process and which contain Bisphenol A, isomers, trisphenols and other by-products, are subjected to a thermal decomposition at a temperature from 210 to 250°C in the presence of basic catalysts and to a vacuum distillation, the resulting distillate is diluted using a phenolic fraction and contacted with the macroporous cation- exchanger at a temperature from 65 to 95°C, whereupon it is made to flow to Step I of suspension-crystallization or is combined with the feed to the Bisphenol A synthesis reactor, while the residue after thermal decomposition, containing mainly heavy ends and polymers, is removed from the process.

Example 1

An 85-m³ reactor having filtration-slot nozzles located at three levels, which is packed with a solid bed of Purolite CT 124/3539 catalyst in which 21% of its functional groups have been neutralized with 2,2-dimethyl-l,3-thiazolidine, is filled from top with a feed mixture at a temperature of 62°C, containing phenol and 3.7% acetone, 11.2% Bisphenol A, 8,2% by-products, including 4.1% of the 2,4-isomer of Bisphenol A, 0.6% of 4-isopropylphenol and 0.8% of 4-tertbutylphenol and 0.3% of water. The mixture is contacted, while flowing downwards, with the catalyst located in the first zone of the reactor, above its top nozzles. The resulting reaction mixture at a temperature of 78°C, containing 23.4% of Bisphenol A, is taken out via the top nozzles and into a 15-m³ tank equipped with a heat exchanger. Once there, it is cooled down to a temperature of 64°C while adding acetone to obtain its concentration of 3.1% and is made to flow again to the reactor via its middle nozzles, so that 4/5 of the stream from the middle nozzles is made to flow downwards through the catalyst bed, which is located between the bottom and middle nozzles and is taken out as a final post-reaction mixture, containing 28.4% Bisphenol A, while 1/5 of the stream is made to flow upwards to be contacted with the catalyst which is located between the middle and top nozzles and is taken out of the reactor via its top nozzles together with a stream of the reaction mixture resulting from contacting the feed with the catalyst, located above the top nozzles.

The resulting post-reaction mixture is contacted with the Dowex 550A anion exchanger and is made to flow to a thin-film evaporator where 20% of a fraction composed of acetone, water and phenol is distilled off, whereupon it is cooled down to 58 °C and subjected to a two-step suspension-crystallization.

A crude adduct after Step I of crystallization is separated using a drum filter. A pure adduct after Step II of crystallization is separated by centrifugation.

The pure adduct is sent to the thin-film evaporator to distill off the phenol, obtaining a crude Bisphenol A with a phenol content of 1.4%.

Any residual phenol is removed from the crude Bisphenol A by steam- stripping in the distillation column whereby a final Bisphenol A product with the following parameters is obtained: purity 99.93%, coloration 5 APHA units, and free phenol content of 15 ppm.

A filtrate, resulting from adduct separation by filtration after Step I of crystallization, which contains phenol, Bisphenol A, isomers, trisphenols and other by-products, is contacted in the reactor with a macroporous ion-exchange resin at a temperature 55-85°C which leads to the isomerization and rearrangement of byproducts into Bisphenol A. Part of the filtrate, which constitutes 4.8% of the stream, is subjected to distillation in the thin-film evaporator and the resulting bottoms, which contains Bisphenol A, isomers, trisphenols and other by-products, is subjected to thermal decomposition at a temperature from 210 to 250°C in the presence of basic catalysts and to vacuum distillation, and the resulting distillate is diluted with a phenolic fraction and contacted with the macroporous cation-exchanger at a temperature from 65 to 95°C whereupon it is made to flow to Step I of suspension- crystallization or is combined with the feed to the Bisphenol A synthesis reactor, while the residue after thermal decomposition, containing mainly heavy ends and polymers, is removed from the process.

In Step II, after 6 months of continuous operation of the reactor, its mode of operation is changed as follows:

- the feed, of which the composition is as stated above, is introduced into the reactor via its top nozzles. The reaction mixture is made to flow downwards and - via the middle nozzles (2/5 of the stream) and the bottom nozzles (3/5 of the stream) - it is taken outside as a final post-reaction mixture, later to be processed in the same manner as was described previously.

In Step III, after 15 months, the feed mixture of which the composition is as stated earlier, is introduced into the reactor via its middle nozzles. The reaction mixture is made to flow downwards and is taken out through the bottom nozzles as a final post-reaction mixture. Example 2

The reaction is carried out as in Example 1, except that the bottom section of the reactor is packed with 2.5-cm diameter beads up to a level of 50 cm above the bottom head of the reactor.

In Step II of the process as described in Example 1 a stream, in the amount of 1/15 of the feed to the reaction, containing phenol and 7.9% by-products, including 3.7% of the 2,4-isomer of Bisphenol A and 0.4% of the 2,2-isomer of Bisphenol A is fed to the top of the reactor.

A Bisphenol-A product with the following parameters was obtained: purity 99.93%, color 4 APHA units, free phenol content 20 ppm.

Claims

1. A method to obtain Bisphenol A from phenol and acetone in the presence of a catalyst in the form of an acidic ion-exchange resin, in which part of its sulfonic groups have been neutralized with 2,2-dimethyl-l,3-thiazolidine or cysteamine, in a single reactor which is divided into three reaction zones by filtration-slot nozzles, with part of or the entire mixture feed for the reaction, which contains phenol and 3 - 6% acetone and the reaction byproducts and which is introduced at a temperature 50-75⁹C to top of the reactor and is made to flow downwards through the catalyst which is above the top nozzles, whereupon part of or the entire post-reaction mixture is directed outside the reactor through its top nozzles as a final post-reaction mixture, or part of or the entire mixture is made to flow via a heat exchanger, where it is cooled down to a temperature 55-75⁹C, acetone is added to obtain its concentration in the range 2-7 %, characterized in, that the reaction mixture from the top nozzles, after being cooled down and enriched with acetone, is fed via the middle or bottom nozzles into the reactor, where part of or the entire reaction mixture flows downwards or upwards in the reactor and is taken out of the reactor as a final post- reaction mixture via its bottom or middle nozzles, respectively, whereas the remaining portion of the reaction mixture from the middle nozzles flows upwards and is taken out of the reactor via its top nozzles, and then, in Step II of the operation, the reactor is filled, via its top or middle nozzles, with a feed stream, containing phenol and 3-6% of acetone and the reaction byproducts, which flows downwards or upwards, respectively, and is taken out of the reactor via its bottom and/or middle nozzles as a final post-reaction mixture.

2. A method according to claim 1, characterized in, that in Step III of the operation, a feed mixture is introduced into the reactor via its middle nozzles which contains phenol and 3 - 6% of acetone and the reaction byproducts, and which flows downwards and is taken out of the reactor through its bottom nozzles as a final post-reaction mixture.

3. A method according to claim 1, characterized in, that the bottom section of the reactor is packed with beads 1-5 cm in diameter, up to a level of 20-60 cm above the bottom head of the reactor.

4. A method according to claim 1, characterized in, that in Steps II and II of the operation a stream is fed to top of the reactor, which contains the reaction by-products, including the 2,4-isomer of Bisphenol A, 2,2-isomer of Bisphenol A in an amount of not less than 1/20 of the reaction feed stream which, at that time, is made to flow to the top or middle nozzles.

5. A method according to claim 1, characterized in, that the final post-reaction mixture from the Bisphenol A synthesis reactor is made to flow into the reactor to be contacted with the anion-exchanger prior to being sent to an evaporator, in which a fraction in the amount of 10 - 30% of the feed stream, containing acetone, water and phenol, is distilled off and the bottoms is made to flow to a one- or two-stage suspension-crystallization, and filtration or centrifugation, whereby a Bisphenol A-phenol adduct is obtained which is made to flow to the evaporator to distill off the phenol to obtain its concentration in the bottoms in the range 0.5 - 3% and then to the column's evaporator to remove any residual phenol whereby Bisphenol A is obtained.

6. A method according to claim 1, characterized in, that the resulting final post-reaction mixture is contacted, at a temperature 55 - 87SC, with an anion exchanger.

7. A method according to claim 1, characterized in, that Bisphenol A is separated from the resulting final post-reaction mixture by distilling-off of acetone, water and phenol.

8. A method according to claim 5, characterized in, that the resulting Bisphenol A is subjected to a falling-film fractional crystallization.

9. A method according to claim 5, characterized in, that the streams that result from the process, which contain Bisphenol A, isomers, trisphenols, and other by-products, are contacted in the reactor with a macroporous ion-exchange resin at a temperature in the range 55-85 °C, which leads to the isomerization and rearrangement of by-products into Bisphenol A.

10. A method according to claim 5, characterized in, that the streams that result from the process, which contain Bisphenol A, isomers, trisphenols and other by-products are subjected to thermal decomposition at a temperature from 210 to 250°C in the presence of basic catalysts and to a vacuum distillation and the resulting distillate is diluted using a phenolic fraction and contacted with the macroporous cation-exchanger at a temperature from 65 to 95°C whereupon it is made to flow to Step I of suspension-crystallization or is combined with the feed to the Bisphenol A synthesis reactor, while the residue after thermal decomposition, containing mainly heavy ends and polymers, is removed from the process.