Process for making bisphenol A (BPA) in the presence of α-methylstyrene

Abstract

The present invention relates to a process for making bisphenol A in the presence of α-methylstyrene without poisoning the catalyst system comprising an ion exchange resin catalyst and a sulfur-containing cocatalyst. Additionally, the present invention provides a process for making polycarbonate.

Description

[Technical field]

[0001] The present invention relates to a process for making bisphenol A and to a process for making polycarbonate. [Background technology]

[0002] Bisphenol A, or BPA, is an important monomer in the production of polycarbonate or epoxy resins. BPA is usually used in the form of para,para-BPA (2,2-bis(4-hydroxyphenol)propane; p,p-BPA), but ortho,ortho-BPA (o,o-BPA) and / or ortho,para-BPA (o,p-BPA) may also be formed in the production of BPA. When referring to BPA, it is primarily para,para-BPA, but also includes small amounts of ortho,ortho-BPA and / or ortho,para-BPA.

[0003] According to the current state of the art, BPA is produced by reacting phenol with acetone in the presence of an acid catalyst to obtain bisphenol. Previously, hydrochloric acid (HCl) was used in the commercial process of the condensation reaction. Currently, a heterogeneous continuous process for the production of BPA is used in the presence of an ion exchange resin catalyst, where the ion exchange resin comprises a crosslinked acid-functionalized polystyrene resin. The most important resin is polystyrene crosslinked by sulfonic acid groups. Divinylbenzene is most used as a crosslinking agent, as described in US Pat. No. 5,399,411; US ​​Pat. No. 5,499,523; US Pat. No. 5,599,633; and US Pat. No. 5,633,665, or in Non-Patent Document 1.

[0004] To achieve high selectivity, the reaction of phenol with acetone can be carried out in the presence of a suitable cocatalyst. US Pat. No. 5,399,433 and US Pat. No. 5,499,466 describe a process for making bisphenol A in the presence of an ion exchange catalyst and mercaptopropionic acid or mercaptan as a cocatalyst. It is known that catalysts deactivate over time. Deactivation is described, for example, in US Pat. No. 5,499,433, US Pat. No. 5,499,466 and US Pat. No. 5,599,466. One of the main objectives of the manufacturing process is to maximize the performance and residence time of the catalyst system. Therefore, to accommodate this objective, it is necessary to identify potential poisons, by-products, impurities in educts, etc.

[0005] US Patent No. 5,399,663 teaches the use of a specific catalyst system including an ion exchange resin catalyst and a sulfur-containing cocatalyst, the cocatalyst being chemically bound to the ion exchange resin catalyst, and also teaches a process for catalyzing the condensation reaction of phenols with ketones using the specific catalyst system. US Patent No. 5,399,663 further discloses a process for catalyzing the condensation reaction of phenols with ketones without utilizing a bulk promoter that is not chemically bound to the ion exchange resin catalyst.

[0006] Similarly, US Pat. No. 5,399,633 describes a process for making bisphenols in the presence of an acidic ion-exchange resin catalyst modified with a particular cationic compound.

[0007] Patent Document 12 describes the production of BPA based on bio-derived phenol and / or bio-derived acetone in the presence of bio-derived impurities in the extract. This document describes the use of promoter-bound ion-exchange resin catalysts, i.e., ion-bound ion-exchange resin catalysts with a promoter chemically bound (i.e., ionically bound). Catalyst poisoning is not considered in this prior art document.

[0008] Alpha-methylstyrene (hereinafter sometimes referred to as "AMS") is one of the impurities that may be present in the raw phenol. As mentioned above, it is common to try to avoid impurities or reduce their amount as much as possible in order to avoid any side reactions, catalyst poisoning, etc. in the desired reaction.

[0009] Removal of AMS from raw phenol (whether fossil-based or bio-based) takes time and money, which makes the raw phenol more expensive. Ultimately, this increases the cost of bisphenol A and the respective polymers prepared from it. Furthermore, the concentration of AMS in raw phenol varies depending on the source and purification process of these feedstocks. This means that different feedstock qualities need to be accommodated (e.g., if the specification is above a certain threshold, another purification step needs to be performed), reducing flexibility in the selection of process and raw material source. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] British Patent No. 849965 [Patent Document 2] U.S. Patent No. 4,427,793 [Patent Document 3] European Patent Application Publication No. 0007791 [Patent Document 4] European Patent Application Publication No. 0621252 [Patent Document 5] US Patent Application Publication No. 2005 / 0177006 [Patent Document 6] U.S. Patent No. 4,859,803 [Patent Document 7] European Patent Application Publication No. 0583712 [Patent Document 8] European Patent Application Publication No. 10620041 [Patent Document 9] DE 14312038 [Patent Document 10] International Publication No. 2012 / 150560 [Patent Document 11] European Patent Application Publication No. 1520617 [Patent Document 12] U.S. Patent No. 8,247,619 [Non-patent literature]

[0011] [Non-Patent Document 1] Chemistry and properties of crosslinked polymers, edited by Santokh S. Labana, Academic Press, New York 1977 Summary of the Invention

[0012] The present invention therefore aimed to provide a process for making ortho,para-bisphenol A, ortho,ortho-bisphenol A, and / or para,para-bisphenol A via condensation of phenol with acetone, which is more economical than the prior art processes. Furthermore, the present invention aimed to provide a process for making ortho,para-bisphenol A, ortho,ortho-bisphenol A, and / or para,para-bisphenol A via condensation of phenol with acetone, which allows more flexibility and / or allows greater flexibility in the choice of the quality of the raw phenol. This flexibility is preferably provided with respect to the concentration of α-methylstyrene as an impurity in the raw phenol.

[0013] At least one of the above problems, preferably all of these problems, have been solved by the present invention. Surprisingly, it has been found that a catalyst system comprising an ion exchange resin catalyst and a sulfur-containing cocatalyst is less susceptible to catalyst poisoning by α-methylstyrene. Furthermore, it has been found that a catalyst system comprising an ion exchange resin catalyst and a sulfur-containing cocatalyst, where at least a portion of the sulfur-containing cocatalyst is not covalently or ionically bonded (i.e., not chemically bonded) to the ion exchange resin catalyst, is less susceptible to catalyst poisoning by α-methylstyrene. Furthermore, the prior art teaches that the amount of AMS in the feed phenol should be as low as possible. Since the specific catalyst system of the present invention is not affected by this impurity, cheaper feed phenol can be used without the risk of shortening the catalyst life. This makes the overall process more cost-effective. Also, the process is more environmentally advantageous since less energy is required to purify the feed. Furthermore, the process allows more flexibility in the choice of feed phenol quality, in particular the concentration of α-methylstyrene in these feeds.

[0014] Thus, the present invention provides (a) condensing feed phenol and feed acetone in the presence of a catalyst system, the catalyst system comprising an ion exchange resin catalyst and a sulfur-containing cocatalyst; 1. A process for making ortho,para-bisphenol A, ortho,ortho-bisphenol A, and / or para,para-bisphenol A, comprising: The amount of alpha-methylstyrene present in step (a) is greater than 1 ppm, based on the total weight of the feed phenol.

[0015] Surprisingly, according to the present invention, it was found that almost all AMS is believed to react during process step (a). This was confirmed by the fact that almost no AMS was detected after process step (a) (see AMS "out" in the experimental part). On the other hand, it was found that AMS is believed to react almost completely to 4-cumylphenol (only a very small amount of the unknown compound was detected). Since this reaction occurred during process step (a) and no catalyst poisoning was detected, it is inferred that 4-cumylphenol is also not a catalyst poison in process step (a). Furthermore, additional experiments were performed and it was found that 4-cumylphenol is a stable molecule in process step (a). This means that 4-cumylphenol is believed to not react in process step (a) (see that the same amount of 4-cumylphenol that spiked in process step (a) was found at the completion of process step (a)).

[0016] According to the invention, reference is made to "raw phenol" and / or "raw acetone". The term "raw" is used for the unreacted extractives applied, especially added, in the process of making BPA. In particular, this term is used to distinguish between phenol newly added to the reaction (as raw phenol) and phenol recycled in the process of making BPA (recycled phenol). Such recycled phenol does not have the possibility of adding additional AMS to the process. The same is true for acetone newly added to the reaction (as raw acetone) and acetone recycled in the process of making BPA (recycled acetone). When referring to phenol and / or acetone, it is preferred to mean either the chemical compounds themselves or the sum of both raw phenol and recycled phenol and / or raw acetone and recycled acetone, unless otherwise specified.

[0017] AMS are impurities in raw phenol, which is one of the products of the reaction of BPA. Raw phenol may contain AMs impurities. For example, routes to manufacture phenol are described in Arpe, Hans-Juergen, Industrielle Organische Chemie, 6. Auflage, January 2007, Wiley-VCH. In particular, processes to make phenol are described in Ullmann's Encyclopedia of Industrial Chemistry, chapter Phenol and Phenol Derivatives. The oxidation of cumene, also known as the Hock process, is by far the major route to synthesis of phenol. Among the poisons formed during the manufacture of phenol is α-methylstyrene.

[0018] The process of the present invention is characterised in that the amount of α-methylstyrene present in step (a) is greater than 1 ppm, preferably greater than 2 ppm, more preferably greater than 3 ppm, even more preferably greater than 4 ppm, even more preferably greater than 5 ppm, even more preferably greater than 6 ppm, even more preferably greater than 7 ppm, even more preferably greater than 8 ppm, even more preferably greater than 9 ppm, even more preferably greater than 10 ppm, even more preferably greater than 11 ppm, even more preferably greater than 12 ppm, even more preferably greater than 15 ppm, even more preferably greater than 20 ppm, even more preferably greater than 25 ppm, even more preferably greater than 50 ppm, even more preferably greater than 75 ppm and most preferably greater than 100 ppm, based on the total weight of the feed phenol.

[0019] Further, it is preferred that the amount of AMS present in step (a) is greater than 1 ppm and not more than 5000 ppm, more preferably not more than 4500 ppm, even more preferably not more than 4000 ppm, even more preferably not more than 3500 ppm, even more preferably not more than 3000 ppm, even more preferably not more than 2500 ppm, and most preferably not more than 2000 ppm, based on the total weight of the raw phenol. It is understood that the upper limit values ​​presented here can be combined with the preferred lower limit values ​​presented above. Methods for determining the amount of AMS in the raw phenol are known to those skilled in the art. For example, the amount of AMS in the raw phenol can be determined according to ASTM D6142-12 (2013).

[0020] According to the present invention, "ppm" preferably refers to parts by weight.

[0021] Preferably, the process of the invention is characterized in that step (a) is carried out in the additional presence of 4-cumylphenol.

[0022] In reaction step (a), 4-cumylphenol was detected as an AMS by-product according to the present invention. Without being bound by theory, it is believed that phenol reacts with AMS. However, since almost no catalyst deactivation was observed, it is believed that this impurity (and all other possible impurities) do not poison the catalyst, at least in small amounts. Furthermore, these impurities can be present in process step (a) if the phenol fraction of step (b) is recycled in process step (c).

[0023] Preferably, the process of the present invention comprises: (b) separating the mixture obtained after step (a) into a bisphenol A fraction comprising at least one of ortho,para-bisphenol A, ortho,ortho-bisphenol A, or para,para-bisphenol A, and a phenol fraction, The phenol fraction is characterized in that it additionally contains unreacted phenol and at least one impurity, preferably 4-cumylphenol, formed due to the presence of α-methylstyrene in step (a).

[0024] The bisphenol A fraction is preferably recovered as a product and / or further purified. There are several variations in the manufacturing process to provide high purity bisphenol. This high purity is particularly important in the use of BPA as a monomer in the manufacture of polycarbonates. WO 0172677 describes crystals of an adduct of bisphenol with phenol and a method for producing the crystals and ultimately making bisphenol. It has been found that high purity para,para-BPA can be obtained by crystallization of the adduct. EP 1944284 describes a process for producing bisphenol, in which the crystallization comprises a continuous suspension crystallizer. It is stated that there is an increasing demand for the purity of BPA and that the disclosed method allows very pure BPA of more than 99.7% to be obtained. WO 2005075397 describes a process for producing bisphenol A, in which the water formed during the reaction is removed by distillation. In this way, unreacted acetone is recovered and recycled, resulting in an economically advantageous process.

[0025] The process of the invention is preferably characterized in that the separation in step (b) is carried out using a crystallization method. It is further preferred that the separation in step (b) is carried out using at least one continuous suspension crystallizer. According to the invention, it has been found that a part of the 4-cumylphenol formed in process step (a) is not separated from BPA in process step (b). This means that at least a part of the 4-cumylphenol formed in process step (a) is present in the bisphenol A fraction of process step (b).

[0026] It was further described that a mother liquor cycle is used. After the reaction, the BPA is removed from the solvent by crystallization and filtration. The mother liquor typically contains 5% to 20% BPA dissolved in unreacted phenol and by-products. Furthermore, water is formed during the reaction, which is removed from the mother liquor in a dehydration section. The fraction containing unreacted phenol is preferably recycled for further reaction, which preferably means recycling the mother liquor. This fraction is reused as unreacted phenol in the reaction with acetone to obtain BPA. The mother liquor stream is preferably recycled to the reaction unit according to conventional methods.

[0027] Typically, by-products in the mother liquor are, for example, o,p-BPA, o,o-BPA, substituted indenes, hydroxyphenylindanols, hydroxyphenylchromans, substituted xanthenes, and higher condensed compounds. Also, as a result of acetone self-condensation and reaction with impurities in the feedstock, further secondary compounds such as anisole, mesityl oxide, mesitylene, and diacetone alcohol may be formed.

[0028] Recycling of the mother liquor can lead to the accumulation of by-products in the circulation stream, which can lead to further deactivation of the catalytic system. This means that when using the catalyst for long periods of time, it is necessary to consider the influence of by-products that may arise in the reaction itself, either from the reaction of phenol with acetone or from the reaction of one of the impurities, as well as the influence of initial impurities in the extract.

[0029] More preferably, the process of the present invention is characterized in that at least one impurity formed due to the presence of α-methylstyrene in step (a) is 4-cumylphenol.

[0030] More preferably, the process according to the invention comprises the steps of: (c) comprising an additional step of using at least a portion of the phenol fraction obtained in step (b) as an extract in step (a).

[0031] It is further preferred that said portion of the phenol fraction comprises at most 5 wt. %, more preferably at most 2 wt. %, and most preferably at most 1 wt. % AMS, where the weight percentage of AMS refers to said portion of AMS compared to the AMS present in the starting phenol.

[0032] In order to avoid the accumulation of by-products and / or impurities formed due to the presence of α-methylstyrene in step (a), the system has several options. The options include, inter alia, a purge stream, waste water, off-gas and BPA itself as product. The main stream seems to be a purge stream, which for example discharges part of the mother liquor. Another approach involves passing a part of the total amount of the circulating stream after the solid-liquid separation and before or after the removal of water and residual acetone, through a rearrangement unit, for example filled with an acid ion exchanger. In this rearrangement unit, a part of the by-products from the preparation of BPA isomerized to obtain p,p-BPA. It has been found that the new impurities formed due to the presence of AMS in process step (a) can be at least partially removed by the purge stream. It is therefore preferred to use at least a part of the phenol fraction obtained in step (b) as extract in step (a) and to purge at least a part of this stream. It is preferred to use more than 50% by volume of the phenol fraction obtained in step (b) as extract in step (a), where the volume percentage is relative to the total volume of the phenol fraction.

[0033] Furthermore, it has been found that some of the impurities formed due to the presence of AMS in process step (a), preferably 4-cumylphenol, are still present in the BPA obtained using standard methods for purifying BPA, for example, some of the impurities formed due to the presence of AMS in process step (a), preferably 4-cumylphenol, are still present in the BPA obtained even after carrying out the process step (b) described above.

[0034] According to the present invention, a catalyst system is used that comprises an ion exchange resin and a sulfur-containing cocatalyst. These catalyst systems are known to those skilled in the art. In particular, there are two different types of catalyst systems: one is mainly referred to as "promoted catalyst" and the other is mainly referred to as "unpromoted catalyst". Promoted catalysts comprise a cocatalyst that is bound to a portion of the ion exchange resin. This bond is either ionic or covalent in nature. Examples of such promoted catalyst systems are described, for example, in US Pat. No. 5,414,151, ...

[0035] Ion exchange resins that can be used in the process of the present invention are known to those skilled in the art. The catalyst system is preferably an acidic ion exchange resin. Such an ion exchange resin may have a crosslinking of 2% to 20%, preferably 3% to 10%, most preferably 3.5% to 5.5%. The acidic ion exchange resin may preferably be selected from the group consisting of sulfonated styrene divinylbenzene resin, sulfonated styrene resin, phenol formaldehyde sulfonic acid resin, and benzene formaldehyde sulfonic acid. Furthermore, the ion exchange resin may contain sulfonic acid groups. The catalyst bed may be either a fixed bed or a fluidized bed.

[0036] Furthermore, the catalyst system of the present invention includes a sulfur-containing cocatalyst. The sulfur-containing cocatalyst can be one substance or a mixture of at least two substances. Preferably, the sulfur-containing cocatalyst is selected from the group consisting of mercaptopropionic acid, hydrogen sulfide, alkyl sulfides such as ethyl sulfide, mercaptoalkylpyridines, mercaptoalkylamines, thiazolidines, aminothiophenols, and mixtures thereof. In the case of the promoted catalyst, the sulfur-containing cocatalyst is preferably selected from mercaptoalkylpyridines such as 3-mercaptomethylpyridine, 3-(2-mercaptoethyl)pyridine, and 4-(2-mercaptoethyl)pyridine; mercaptoalkylamines such as 2-mercaptoethylamine, 3-mercaptopropylamine, and 4-mercaptobutylamine; thiazolidines such as thiazolidine, 2-2-dimethylthiazolidine, 2-methyl-2-phenylthiazolidine, and 3-methylthiazolidine; aminothiophenols such as 4-methylthiophenol, and mixtures thereof. In the case of unpromoted catalysts, the sulfur-containing cocatalyst is selected from the group consisting of mercaptopropionic acid, hydrogen sulfide, alkyl sulfides such as ethyl sulfide, and mixtures thereof. According to the present invention, it is preferred to use an unpromoted catalyst system, which means that in the catalyst system, at the start of process step (a), at least a part of the sulfur-containing cocatalyst, preferably at least 75 mole %, is preferably not covalently or ionically bonded to the ion exchange resin catalyst.

[0037] Preferably, the co-catalyst is dissolved in the reaction solution of process step (a). More preferably, the co-catalyst is homogeneously dissolved in the reaction solution of process step (a). The process of the present invention is preferably characterized in that the sulfur-containing co-catalyst is selected from the group consisting of mercaptopropionic acid, hydrogen sulfide, alkyl sulfides such as ethyl sulfide, and mixtures thereof. Most preferably, the sulfur-containing co-catalyst is 3-mercaptopropionic acid.

[0038] The catalyst system of the present invention comprises a sulfur-containing cocatalyst, and preferably, all of the sulfur-containing cocatalyst is not covalently or ionically bonded to the ion-exchange resin catalyst. This means that preferably, all of the sulfur-containing cocatalyst is added in process step (a). According to the present invention, the expressions "not chemically bonded" or "not covalently or ionically bonded" refer to a catalyst system in which, at the start of process step (a), there are no covalent or ionic bonds between the ion-exchange resin catalyst and the sulfur-containing cocatalyst. However, this does not mean that at least a part of the sulfur-containing cocatalyst may be fixed to the heterogeneous catalyst matrix via ionic or covalent bonds. In any case, at the start of process step (a), such ionic or covalent bonds of the sulfur-containing cocatalyst are not present and, if they are formed at all, they are formed over time. Therefore, it is preferred to add the sulfur-containing cocatalyst to process step (a). The term "addition" denotes an active process step. This means that, as mentioned above, it is preferred to dissolve the cocatalyst in the reaction solution of process step (a). Additionally, the co-catalyst may be added in any other process step or may be added more than once in process step (a). Furthermore, it is preferred that the majority of the sulfur-containing co-catalyst is not covalently or ionically bonded to the ion exchange resin catalyst. This means that at least 75 mol %, more preferably at least 80 mol %, and most preferably at least 90 mol % of the sulfur-containing co-catalyst is not chemically bonded to the ion exchange resin catalyst, where the mol % is relative to the total co-catalyst present in process step (a).

[0039] Since AMS is a common impurity in feed phenol, it is preferred that the AMS present in step (a) is introduced into process step (a) as an impurity in the feed phenol. In this situation, at least a portion of the AMS may be present in process step (a) for other reasons. For example, some of the AMS present in process step (a) may be present due to phenol recycle. However, it is preferred that the phenol recycle does not add substantially any additional AMS to process step (a).

[0040] According to the present invention, the raw phenol and / or raw acetone used in process step (a) can be bio-based. When used according to the present invention, the term "bio-derived" or "bio-based" refers to (raw) phenol and / or (raw) acetone obtained from currently renewable resources. In particular, the term is used as opposed to phenol derived from fossil fuels. Whether a raw material is bio-based can be confirmed by measuring the carbon isotope level, since the relative amount of the carbon isotope C14 is lower in fossil fuel materials. Such measurements are known to the skilled person, which can be carried out, for example, according to ASTM D6866-18 (2018) or ISO16620-1 to -5 (2015).

[0041] In another aspect, the present invention provides a method for producing a pharmaceutical composition comprising: (i) in any or preferred embodiment, obtaining ortho,para-bisphenol A, ortho,ortho-bisphenol A, and / or para,para-bisphenol A by the process of the present invention; (ii) polymerizing the ortho,para-bisphenol A, ortho,ortho-bisphenol A, and / or para,para-bisphenol A obtained in step (i), optionally in the presence of at least one further monomer, to obtain a polycarbonate; The present invention provides a process for making a polycarbonate comprising:

[0042] As explained above, the process for producing ortho,para-bisphenol A, ortho,ortho-bisphenol A, and / or para,para-bisphenol A of the present invention provides BPA that can be obtained in a more economical and / or environmentally friendly manner. Therefore, the use of this BPA obtained by the process according to the present invention also makes the process for making polycarbonate according to the present invention more economical and / or environmentally friendly.

[0043] Reaction step (ii) is known to those skilled in the art. The polycarbonates can be prepared in known manner from BPA, carbonic acid derivatives, optional chain terminators, and optional branching agents by interphase phosgenation or melt transesterification.

[0044] In interphase phosgenation, the bisphenol and any branching agent are dissolved in an aqueous alkaline solution and reacted with a carbonic acid source, such as phosgene, optionally dissolved in a solvent, in a two-phase mixture containing an aqueous alkaline solution, an organic solvent and a catalyst, preferably an amine compound. The reaction procedure can also be carried out in several stages. Such processes for making polycarbonates are known in principle as interfacial processes, for example in H. Schnell, Chemistry and Physics of Polycarbonates, Polymer Reviews, Vol. 9, Interscience Publishers, New York 1964 page 33 et seq. and Polymer Reviews, Vol. 10, "Condensation Polymers by Interfacial and Solution Methods", Paul W. Morgan, Interscience Publishers, New York 1965, chapter VIII, page 325, so that the basic conditions are well known to those skilled in the art.

[0045] Alternatively, polycarbonates can also be prepared by melt transesterification process.The melt transesterification process is described, for example, in Encyclopedia of Polymer Science, Vol. 10 (1969), Chemistry and Physics of Polycarbonates, Polymer Reviews, H. Schnell, Vol. 9, John Wiley and Sons, Inc. (1964), and in German Patent Application Publication No. 1031512.In the melt transesterification process, the aromatic dihydroxy compounds already described in the interfacial process are transesterified with carbonic acid diesters in the melt with the aid of suitable catalysts and any further additives.

[0046] Preferably, the process for making polycarbonate according to the invention is characterized in that process step (i) further comprises a step of purifying ortho,para-bisphenol A, ortho,ortho-bisphenol A and / or para,para-bisphenol A in order to reduce the amount of at least one impurity formed due to the presence of AMS in step (a). As mentioned above, cheaper raw phenols can be used in the process of the invention. However, if AMS is present as an impurity in these cheaper raw materials, other impurities are formed. These impurities are preferably removed before polymerization. In another preferred embodiment, this purification step is not carried out in order to reduce the amount of at least one impurity formed due to the presence of AMS in step (a). This does not exclude carrying out a purification process step in order to reduce the amount of other impurities present due to the reaction of process step (a). In the case of carrying out such a purification step, it is not excluded that the amount of impurities formed due to the presence of AMS in process step (a) in the obtained product is reduced. As mentioned above, the main impurity believed to form is 4-cumylphenol, which is believed to be present in the BPA obtained in process step (i). 4-cumylphenol is a common chain terminator in the polymerization of BPA to polycarbonate, particularly when the interphase phosgenation process is used. The process for making polycarbonate according to the present invention is preferably an interphase phosgenation process using at least one chain terminator in step (ii).

[0047] Knowing the amount of AMS present in the starting phenol, the skilled artisan can calculate and / or measure the amount of 4-cumylphenol formed during process step (a) and / or present in the BPA in process step (i). Thus, the skilled artisan can easily determine any purification factor required if a purification step is performed to increase the purity of the BPA obtained in process step (i). Knowing the amount of 4-cumylphenol present in the BPA, the skilled artisan can adjust the amount of additional chain terminator used in process step (ii). Thus, the present invention provides a means to reduce the amount of (additional) chain terminator used in the polymerization of BPA by using impurities present in the starting phenol that subsequently react to 4-cumylphenol. This 4-cumylphenol can then be used as at least a part of the chain terminator required for the polymerization of BPA. Thus, in the process of making the polycarbonates of the present invention, the chain terminator is preferably introduced into the process simultaneously with ortho,para-bisphenol A, ortho,ortho-bisphenol A, and / or para,para-bisphenol A. This means that, preferably, the BPA contains the chain terminator. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS EXAMPLES

[0048] The materials used in the examples are as follows:

[0049] TIFF2024507888000001.tif63170

[0050] The column reactor was equipped with 150 g of phenol wet catalyst (amount of phenol wet catalyst in the reactor: 210 ml-230 ml). The column reactor was heated to 60° C. (catalyst bed temperature during the reaction: 63° C.). A mixture of phenol, acetone (3.9 wt %), and MEPA (160 ppm relative to the total mass of phenol and acetone) was prepared and heated to 60° C. This mixture was pressed into the column reactor at a flow rate of 45 g / h. The column reactor had a sampling point at the bottom. Various samples were taken during the reaction using the opening of the sampling point. The sampling time was 1 hour, and the amount of sample taken every hour was 45 g.

[0051] The first run (standard run) was carried out for 52 hours. Samples were taken and analyzed by GC after 48, 49, 50, and 51 hours.

[0052] A second run (impurity run) was performed for 52 hours. At the beginning of the second run, 1540 ppm of α-methylstyrene (relative to the combined mass of phenol and acetone) was dosed to the reaction system. Samples were taken and analyzed by GC after 48, 49, 50, and 51 hours, respectively. A third run (standard run) was then performed for 52 hours using a new mixture of acetone, phenol, and MEPA. Samples were taken via syringe and analyzed by GC after 48, 49, 50, and 51 hours, respectively. A fourth run (impurity run) was then performed for 52 hours. At the beginning of the fourth run, 1530 ppm of α-methylstyrene (relative to the combined mass of phenol and acetone) was dosed to the reaction system. Samples were taken and analyzed by GC after 48, 49, 50, and 51 hours, respectively. Finally, a fifth run (standard run) was performed for 52 hours. Samples were taken after 48, 49, 50, and 51 hours and analyzed by GC.

[0053] Gas chromatography (GC) of methanol was performed using an Agilent J&W VF-1MS column (100% dimethylpolysiloxane) with dimensions of 50 m x 0.25 mm x 0.25 μm, with a temperature profile of 60° C. for 0.10 min, heating at 12° C. / min to 320° C. and holding at this temperature for 10.00 min, at 300° C. with a 10 / 1 split to inject 1 μl of sample, with a flow rate of 2 ml / min at an initial pressure of 18.3 psi (1.26 bar).

[0054] Gas chromatography (GC) of α-methylstyrene, phenol, para,para-BPA, and 4-cumylphenol was performed using an Agilent J&W VF-1MS column (100% dimethylpolysiloxane) with dimensions of 50 m x 0.25 mm x 0.25 μm, with a temperature profile of 80° C. for 0.10 min, heating at 12° C. / min to 320° C. and holding at this temperature for 10.00 min, with a 10 / 1 split at 300° C. to inject 1 μl of sample, with a flow rate of 2 ml / min at an initial pressure of 18.3 psi (1.26 bar).

[0055] The standard runs represent the reaction of acetone with phenol to form BPA in the presence of catalyst and cocatalyst. From the standard runs, the acetone conversion, including the respective error bars, can be estimated. This conversion represented a baseline for evaluating whether impurities affect the deactivation of the catalyst. The acetone conversion in the third and fifth standard runs was compared with that of the first standard run to determine the effect of α-methylstyrene on the catalyst. If the acetone conversion is lower than this conversion, it indicates that α-methylstyrene affects the BPA catalyst. To show that this type of evaluation can be used to determine catalyst poisoning, a reference run was performed using methanol as an impurity. Methanol is known from the current state of the art to be a known poison for catalysts in the BPA process, as described, for example, in US Pat. No. 8,143,456. The respective results are shown in Table 1. The values ​​shown in the table are the average values ​​obtained from four samples taken during each run (after 48 hours, 49 hours, 50 hours, and 51 hours).

[0056] TIFF2024507888000002.tif44170

[0057] As can be clearly seen from Table 1, the acetone conversion rate decreased in the first, third and fifth standard runs, which means that the catalyst was poisoned by methanol and could not recover the conversion rate due to the irreversible reaction that reduced the catalytic activity.

[0058] The following table shows the results of the first run (standard run), second run (impurity run), third run (standard run), fourth run (impurity run), and fifth run (standard run) for alpha-methylstyrene as an impurity. The values ​​shown in the table are the average values ​​obtained from four samples taken during each run (after 48 hours, 49 hours, 50 hours, and 51 hours).

[0059] TIFF2024507888000003.tif68170

[0060] As can be seen from the results in Table 2, the addition of α-methylstyrene in the reaction of phenol with acetone to para,para-BPA does not cause a decrease in the acetone conversion in the first, third and fifth standard runs. This means that α-methylstyrene is not a poison for the catalyst system used. This effect is seen after each impurity run. Furthermore, it can be seen that during the impurity runs, almost all of the α-methylstyrene reacts (α-methylstyrene OUT cannot be detected). By GC analysis, it was possible to prove that α-methylstyrene was completely reacted to 4-cumylphenol. Since 4-cumylphenol is present in the reaction, it can also be concluded that it is not a poison for the catalyst used, at least in small amounts.

[0061] The stability of 4-cumylphenol during the reaction was also tested using the same set-up as described above for α-methylstyrene, except that 710 ppm of 4-cumylphenol was dosed. Only one run was performed, and the same amount of 4-cumylphenol was detected upon completion.

[0062] Therefore, it can be concluded that the dose of 4-cumylphenol passed completely through the reactor, thus confirming that 4-cumylphenol is a stable molecule in this process.

Claims

1. (a) condensing feed phenol and feed acetone in the presence of a catalyst system, the catalyst system comprising an ion exchange resin catalyst and a sulfur-containing cocatalyst; 1. A process for making ortho,para-bisphenol A, ortho,ortho-bisphenol A, and / or para,para-bisphenol A, comprising:

13. The process of claim 12, wherein the amount of alpha-methylstyrene present in step (a) is greater than 1 ppm based on the total weight of the feed phenol.

2. 2. The process of claim 1, wherein in said catalyst system, at the start of process step (a), at least a portion of said sulfur-containing cocatalyst is not covalently or ionically bonded to said ion exchange resin catalyst.

3. 3. The process according to claim 1 or 2, characterized in that step (a) is carried out in the additional presence of 4-cumylphenol.

4. (b) separating the mixture obtained after step (a) into a bisphenol A fraction comprising at least one of ortho,para-bisphenol A, ortho,ortho-bisphenol A, or para,para-bisphenol A, and a phenol fraction, 4. The process according to claim 1, further comprising a step, wherein the phenol fraction comprises unreacted phenol and at least one impurity formed due to the presence of α-methylstyrene in step (a).

5. 5. The process of claim 4, wherein the at least one impurity formed due to the presence of alpha-methylstyrene in step (a) is 4-cumylphenol.

6. 6. The process according to claim 4 or 5, characterized in that it comprises the additional step of: (c) using at least a portion of the phenolic fraction obtained in step (b) as extract in step (a).

7. 7. The process according to any one of claims 1 to 6, characterized in that the sulfur-containing cocatalyst is selected from the group consisting of mercaptopropionic acid, hydrogen sulfide, alkyl sulfides such as ethyl sulfide, mercaptoalkylpyridines, mercaptoalkylamines, thiazolidines, aminothiophenols, and mixtures thereof.

8. (i) obtaining ortho,para-bisphenol A, ortho,ortho-bisphenol A, and / or para,para-bisphenol A according to the process of any one of claims 1 to 7; (ii) polymerizing the ortho,para-bisphenol A, ortho,ortho-bisphenol A, and / or para,para-bisphenol A obtained in step (i), optionally in the presence of at least one further monomer, to obtain a polycarbonate; A process for making a polycarbonate comprising: