PRODUCTION OF BISPHENOL-A
FIELD OF THE INVENTION
[0001] The present invention relates to an integrated process for producing bisphenol-A and co-producing methyl ethyl ketone.
BACKGROUND OF THE INVENTION
[0002] Bisphenol-A are and methyl ethyl ketone important products in the chemical industry. For example, bisphenol-A, or 4,4'-dihydroxy~2,2- diphenylpropane, is useful in the production of epoxy resins and polycarbonate plastics, whereas methyl ethyl ketone can be used as a solvent for lacquers and resins and for dewaxing of lubricating oils.
[0003] Bisphenol-A is produced commercially by the condensation of acetone and phenol over an acid catalyst and in fact bisphenol-A production is the largest consumer of phenol. Currently, the most common route for the production of phenol is the Hock process. This is a three-step process in which the first step involves alkylation of .benzene with propylene to produce cumene, followed by oxidation of the cumene to the corresponding hydroperoxide and then cleavage of the hydroperoxide to produce equimolar amounts of phenol and acetone. [0004] The production of bisphenol-A consumes two moles of phenol and one mole of acetone for each mole of bisphenol-A produced. Thus, using the Hock process as the source of the phenol leaves an extra mole of acetone to be disposed of in the market place for each mole of bisphenol-A produced. Since the world bisphenol-A growth rate (5-8%/yr) is far in excess of that for acetone (1-3 %/yr), this chain of technologies can result in an excess of low valued acetone in the world solvents market. There is therefore a need for a process for producing bisphenol-A in which the excess of co-produced acetone can be eliminated or, at least reduced.
[0005] According to the invention, the acetone imbalance can be avoided by an integrated process in which part of the required phenol is produced from
cumene, and part is produced from secondary butyl benzene. The cumene is produced by alkylating benzene with a C3 alkylating agent, such as propylene, to produce cumene, which is then oxidized to cumene hydroperoxide, which is subsequently decomposed to phenol and acetone. The secondary butyl benzene is produced by alkylating benzene with a C4 alkylating agent, such as butene, particularly low cost mixed butenes. The secondary butyl benzene can then be oxidized to secondary butylbenzene hydroperoxide, which is subsequently decomposed to produce phenol and methyl ethyl ketone.
[0006] The cumene and secondary butyl benzene are produced in separate reaction zones due to differences in the physical properties of propylene and butenes, and in the alkylation rates of propylene and butenes with benzene. Similarly cumene hydroperoxide and secondary butylbenzene hydroperoxide are preferably produced in separate reaction zones due to the markedly different oxidation rates of cumene and secondary butylbenzene. Carrying out the alkylation and oxidation steps separately allows optimization of the operating conditions of each process step and maximization of the yield of each product. [0007] The integrated process can supply all the required phenol and acetone to produce bisphenol-A, with no net acetone manufacture. The economics of the process are improved in two ways. Firstly, butenes are cheaper per mole than propylene (which is in generally short supply because of strong demand for propylene as a raw material for polypropylene), and secondly, MEK is a higher value product than acetone.
[0008] It is known that phenol and methyl ethyl ketone can be produced by a variation of the Hock process in which sec-butylbenzene is oxidized to obtain sec- butylbenzene hydroperoxide and the peroxide decomposed to the desired phenol and methyl ethyl ketone. An overview of such a process is described in pages 113-421 and 261-263 of Process Economics Report no. 23B entitled "Phenol", published by the Stanford Research Institute in December 1977. [0009] In addition, European Published Application No. 1,088,809 discloses a process for coproducing phenol, methyl ethyl ketone and acetone by the oxidation of a feed mixture containing cumene and up to 25 wt% sec-butylbenzene and the subsequent Hock cleavage of the hydroperoxides, so that the ratio of the
phenol:acetone:methyl ethyl ketone in the product can be controlled via the composition of the feed mixture. The phenol and acetone products can be used in the production of bisphenol-A.
[0010] The feed mixture employed in the process of European Published Application No. 1,088,809 is produced by alkylating benzene with a corresponding mixture of propene and l-butene/2-butene in the presence of a commercial alkylation catalyst such as AlCl3, H3POVSiO2 or a zeolite. However, existing commercial catalysts for the alkylation of benzene with butenes produce not only sec-butylbenzene but also varying amounts of by-products, mainly isobutylbenzene, tert-butylbenzene, dibutylbenzenes and tributylbenzenes. Of these compounds, dibutylbenzenes and tributylbenzenes are readily separated from the reaction mixture and can then transalkylated to produce additional sec- butylbenzene. However, the boiling points of isobutylbenzene, sec-butylbenzene and tert-butylbenzene are 172.8°C, 173.5°C and 169°C, respectively, and hence it is difficult to separate these compounds from each other by distillation. Moreover, isobutylbenzene and tert-butylbenzene are known to be inhibitors to the oxidation of sec-butylbenzene to the corresponding hydroperoxide. For example, the rate of oxidation of sec-butylbenzene, when the sec-butylbenzene contains 1% by weight of isobutylbenzene, decreases to about 91% of that when the sec-butylbenzene is free of isobutylbenzene.
[0011] Therefore, in employing the Hock process to coproduce phenol and methyl ethyl ketone, it is desirable to minimize the amounts of isobutylbenzene and tert-butylbenzene formed as by-products during the alkylation step to produce the sec-butylbenzene. According to a preferred aspect of the invention, it is found that by using molecular sieves of the MCM-22 family as the butene alkylation catalyst, it is possible to produce secondary butylbenzene that is substantially free of tertiary butylbenzene and isobutylbenzene. MCM-22 family zeolites are known aromatics alkylation catalysts, see, for example, U.S. Patent Nos. 4,992,606; 5,371,310 and 5,557,024, but their ability to produce secondary butylbenzene that is substantially free of tertiary butylbenzene and isobutylbenzene is so far unreported.
SUMMARY OF THE INVENTION
[0012] In one aspect, the present invention resides in a process for producing phenol, acetone and methyl ethyl ketone, the process comprising:
(a) contacting benzene and a C3 alkylating agent under first alkylation conditions with an alkylation catalyst in a first reaction zone to produce an alkylation effluent comprising cumene;
(b) contacting benzene and a C4 alkylating agent under second alkylation conditions with an alkylation catalyst in a second reaction zone separate from said first reaction zone to produce an alkylation effluent comprising sec- butylbenzene;
(c) oxidizing the cumene and sec-butylbenzene from (a) and (b), either separately or as a mixture, to produce the corresponding hydroperoxides; and
(d) cleaving the hydroperoxides from (c), either separately or as a mixture, to produce phenol, acetone and methyl ethyl ketone.
[0013] Conveniently, the process further comprises separating the phenol, acetone and methyl ethyl ketone into individual product streams. [0014] Conveniently, the C3 alkylating agent in (a) comprises propylene. [0015] Conveniently, the C4 alkylating agent in (b) comprises a linear butene, for example 1 -butene and/or 2-butene. In one embodiment, said linear butene is contained in a mixed C4 stream which is subjected to at least one of sulfur removal, nitrogen removal, oxygenate removal, butadiene removal and isobutene removal prior to the contacting (b).
[0016] Conveniently, the alkylation catalyst in (a) comprises a molecular sieve selected from zeolite beta, faujasite, mordenite, MCM-22, PSH-3, SSZ-25, ERB-I, ITQ-I, ITQ-2, MCM-36, MCM-49, MCM-56, UZM-8, and mixtures thereof. Preferably, said molecular sieve is selected from MCM-22, PSH-3, SSZ-25, ERB- 1, ITQ-I, ITQ-2, MCM-36, MCM-49, MCM-56, UZM-8, and mixtures thereof. "Mixtures" as used here and throughout this specification and the appendant claims means any two or more items from the relevant list. [0017] In one embodiment, said contacting (a) is conducted under at least partial liquid phase conditions. Conveniently, said first alkylation conditions
include a temperature of up to 2500C, a pressure up to 250 atmospheres (25,000 kPa), a benzene to propylene ratio from about 1 to about 10 and a benzene weight hourly space velocity (WHSV) from about 5 hr"1 to about 250 hr 1. [0018] Conveniently, the alkylation catalyst in (b) comprises a molecular sieve selected from zeolite beta, faujasite, mordenite, MCM-22, PSH-3, SSZ-25, ERB-I, ITQ-I, ITQ-2, MCM-36, MCM-49, MCM-56, UZM-8, and mixtures thereof. Preferably, said molecular sieve is selected from MCM-22, PSH-3, SSZ- 25, ERB-I, ITQ-I, ITQ-2, MCM-36, MCM-49, MCM-56, and UZM-8. [0019] In one embodiment, said contacting (b) is conducted under at least partial liquid phase conditions. Conveniently, said second alkylation conditions include a temperature of from about 60°C to about 260°C, a pressure of 7000 kPa or less, and a feed weight hourly space velocity (WHSV) based on C4 alkylating agent of from about 0.1 to 50 hr"1 and a molar ratio of benzene to C4 alkylating agent from about 1 to 50.
[0020] Conveniently, said sec-butylbenzene contains less than 0.50 wt%, for example less than 0.10 wt%, such as less than 0.05 wt%, of isobutylbenzene and tert-butylbenzene.
[0021] In one embodiment, said alkylation effluent produced in (a) comprises polyisopropylbenzenes and the process further comprises contacting said polyisopropylbenzenes with benzene in the presence of a transalkylation catalyst to produce cumene. Conveniently, the transalkylation catalyst comprises a molecular sieve selected from zeolite beta, faujasite, mordenite, USY, MCM-22, MCM-68, PSH-3, SSZ-25, ERB-I, ITQ-I, ITQ-2, MCM-36, MCM-49, MCM-56, UZM-8, and mixtures thereof.
[0022] In a further embodiment, said alkylation effluent produced in (b) comprises polybutylbenzenes and the process further comprises contacting said polybutylbenzenes with benzene in the presence of a transalkylation catalyst to produce sec-butylbenzene. Conveniently, the transalkylation catalyst comprises a molecular sieve selected from zeolite beta, faujasite, mordenite, USY, MCM-68, MCM-22, PSH-3, SSZ-25, ERB-I, ITQ-I, ITQ-2, MCM-36, MCM-49, MCM-56, UZM-8, and mixtures thereof.
[0023] Conveniently, the oxidizing (c) is conducted in the presence of a catalyst, which can be a homogeneous catalyst or more preferably is a heterogeneous catalyst. In one embodiment, the oxidation of the cumene is conducted in a separate reaction zone from that used to effect oxidation of the sec- butylbenzene.
[0024] Conveniently, the oxidizing (c) is conducted at a temperature of about
7O0C to about 200°C and a pressure of about 50 to about 1000 kPa.
[0025] Conveniently, the cleaving (d) is conducted in the presence of a catalyst, which can be a homogeneous catalyst or more preferably is a heterogeneous catalyst, hi one embodiment, the cleavage of the cumene hydroperoxide is conducted in a separate reaction zone from that used to effect cleavage of the sec-butylbenzene hydroperoxide.
[0026] Conveniently, the cleaving (d) is conducted at a temperature of about
2O0C to about 1500C, such as about 400C to about 1200C, a pressure of about 50 to about 7000 kPa, such as about 100 to about 2860 kPa and a liquid hourly space velocity (LHSV) based on the hydroperoxide of about 0.1 to about 100 hr"1, preferably about 1 to about 50 hr"1.
[0027] Conveniently, at least one of, and preferably each of, the contacting
(a), contacting (b), oxidizing (c) and cleaving (d) is effected by catalytic distillation.
[0028] hi further aspect, the present invention resides in a process for producing bisphenol-A and methyl ethyl ketone, the process comprising:
(a) contacting benzene and a C3 alkylating agent under alkylation conditions with an alkylation catalyst in a first reaction zone to produce an alkylation effluent comprising cumene;
(b) contacting benzene and a C4 alkylating agent under alkylation conditions with an alkylation catalyst in a second reaction zone separate from said first reaction zone to produce an alkylation effluent comprising sec-butylbenzene;
(c) oxidizing the cumene from (a) in a third reaction zone to produce a hydroperoxide;
(d) oxidizing the sec-butylbenzene from (b) in a fourth reaction zone separate from said third reaction zone to produce a hydroperoxide;
(e) cleaving the hydroperoxides from (c) and (d), either separately or as a mixture, to produce phenol, methyl ethyl ketone and acetone;
(f) separating the phenol, methyl ethyl ketone and acetone; and
(g) reacting at least part of the acetone from (f) with at least part of the phenol from (f) to produce bisphenol-A.
[0029] Conveniently, at least one of, and preferably each of, the contacting (a), contacting (b), oxidizing (c), oxidizing (d), cleaving (e) and reacting (g) is effected by catalytic distillation.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0030] The present invention is directed to an integrated process for producing bisphenol-A that coproduces methyl ethyl ketone instead of, or as well as, acetone. The process employs cumene as the source of the acetone and part of the phenol required to produce the bisphenol-A and employs secondary butyl benzene to produce the remainder of the phenol and to coproduce methyl ethyl ketone. [0031] The cumene is produced by alkylating benzene with a C3 alkylating agent, such as propylene. The cumene is then oxidized to cumene hydroperoxide, which is subsequently decomposed to phenol and acetone. The secondary butyl benzene is produced by alkylating benzene with a C4 alkylating agent, such as butene, particularly low cost mixed butenes. The secondary butyl benzene can then be oxidized to secondary butylbenzene hydroperoxide, which is subsequently decomposed to produce phenol and methyl ethyl ketone.
[0032] In view of the differences in the physical properties of propylene and butenes, and in the alkylation rates of propylene and butenes with benzene, the cumene and secondary butyl benzene are produced in separate alkylation reactors. Similarly, in view of the different oxidation rates of cumene and secondary butylbenzene, the cumene hydroperoxide and secondary butylbenzene hydroperoxide are preferably produced in separate oxidation reactors. The cumene and secondary butylbenzene hydroperoxides can be mixed prior to the cleavage step but, more preferably, the cleavage of the cumene hydroperoxide to produce phenol and acetone is conducted in a separate reactor from that used to
effect cleavage of the secondary butylbenzene hydroperoxide into phenol and methyl ethyl ketone.
[0033] Fractionation of the cleavage products produces phenol and acetone product streams, which can then be reacted to produce the desired bisphenol-A, and a methyl ethyl ketone product stream, which can be recovered and sold separately. By controlling the relative amounts of the C3 and C4 alkylating agents being fed to the separate alkylation reactors it is possible to produce bisphenol-A while controlling the amounts of co-produced acetone and methyl ethyl ketone, hi particular, the amount of excess acetone produced by the process can, if desired, be reduced to zero.
Cumene Production
[0034] The benzene employed in the alkylation step to produce cumene can be any commercially available benzene feed, but preferably the benzene has a purity level of at least 99 wt%.
[0035] The alkylating agent can be any aliphatic or aromatic organic compound having one or more available alkylating aliphatic groups capable of reaction with benzene and having 3 carbon atoms. Examples of suitable C3 alkylating agents include propylene; alcohols (inclusive of monoalcohols, dialcohols, trialcohols, etc.), such as n-propanol; aldehydes, such as propionaldehyde; and the propyl chlorides, with propylene being particularly preferred.
[0036] The cumene alkylation catalyst used in the present process comprises a molecular sieve selected from zeolite beta (described in U.S. Patent No. 3,308,069), faujasite, mordenite, including dealuminized mordenite, and members of the MCM-22 family of molecular sieves. Molecular sieves of the MCM-22 family include MCM-22 (described in U.S. Patent No. 4,954,325), PSH-3 (described in U.S. Patent No. 4,439,409), SSZ-25 (described in U.S. Patent No. 4,826,667), ERB-I (described in European Patent No. 0293032), ITQ-I (described in U.S. Patent No 6,077,498), ITQ-2 (described in International Patent Publication No. WO97/17290), MCM-36 (described in U.S. Patent No. 5,250,277), MCM-49 (described in U.S. Patent No. 5,236,575), MCM-56
(described in U.S. Patent No. 5,362,697), UZM-8 (described in U.S. Patent No. 6,756,030), and mixtures thereof. Preferred catalysts are members of the MCM- 22 family.
[0037] The cuniene alkylation catalyst can include the molecular sieve in unbound or self-bound form or, alternatively, the molecular sieve can be combined in a conventional manner with an oxide binder, such as alumina, such that the final alkylation catalyst contains between 2 and 80 wt% sieve. [0038] The cumene alkylation process is conducted such that the organic reactants, i.e., the benzene and C3 alkylating agent, are brought into contact with the alkylation catalyst in a suitable reaction zone such as, for example, in a flow reactor containing a fixed bed of the catalyst composition or in a catalytic distillation reactor, under effective alkylation conditions. Such conditions include a temperature of up to about 2500C, e.g., up to about 15O0C, e.g., from about 100C to about 1250C; a pressure of about 250 atmospheres (25,000 kPa) or less, e.g., from about 1 to about 30 atmospheres (100 to 3,000 kPa); a benzene to propylene ratio from about 1 to about 10 and a benzene weight hourly space velocity (WHSV) from about 5 hr"1 to about 250 hr"\ preferably from about 5 hr" 1 to about 50 hr"1.
[0039] The reactants can be in either the vapor phase or partially or completely in the liquid phase and can be neat, i.e., free from intentional admixture or dilution with other material, or they can be brought into contact with the zeolite catalyst composition with the aid of carrier gases or diluents such as, for example, hydrogen or nitrogen. Conveniently, the total feed to the cumene alkylation step contains less than 1000 ppm, such as less than 500 ppm, for example less than 100 ppm, water. In addition, the total feed typically contains less than 100 ppm, such as less than 30 ppm, for example less than 3 ppm, sulfur and less than 10 ppm, such as less than 1 ppm, for example less than 0.1 ppm, nitrogen.
[0040] Although the alkylation step is highly selective towards cumene, the effluent from the alkylation reaction will normally contain some polyalkylated products, as well as unreacted aromatic feed and the desired monoalkylated species. The unreacted aromatic feed is normally recovered by distillation and
recycled to the cumene alkylation reactor. The bottoms from the benzene distillation are further distilled to separate the cumene product from any polyalkylated products and other heavies. Depending on the amount of polyalkylated products present in the alkylation reaction effluent, it may be desirable to transalkylate the polyalkylated products with additional benzene to maximize the production of the desired monoalkylated species. [0041] Transalkylation with additional benzene is typically effected in a transalkylation reactor, separate from the cumene alkylation reactor, over a suitable transalkylation catalyst, such as an MCM-22 family catalyst, zeolite beta, MCM-68 (see U.S. Patent No. 6,014,018), zeolite Y and mordenite. The transalkylation reaction is typically conducted under at least partial liquid phase conditions. Suitable transalkylation conditions include a temperature of about 500C to about 500°C, a pressure of about 10 kPa to about 3,500 KPa, a weight hourly space velocity of about 0.5 to about 500 hr"1 on total feed and benzene/PIPB weight ratio about 0.1 to about 10.
Sec-Butylbenzene Production
[0042] Again any commercially available benzene feed can be used, but preferably the benzene has a purity level of at least 99 wt%. [0043] The C4 alkylating agent can be any aliphatic or aromatic organic compound having one or more available alkylating aliphatic groups capable of reaction with benzene and having 4 carbon atoms. Examples of suitable C4 alkylating agents include monoolefms, such as linear butenes, particularly butene- 1 and/or butene-2 and preferably butene-2; alcohols (inclusive of monoalcohols, dialcohols, trialcohols, etc.) such as the butanols; aldehydes such as butyraldehyde; and alkyl halides such as the butyl chlorides. [0044] The C4 alkylating agent can also be an olefinic C4 hydrocarbon mixture such as can be obtained by steam cracking of ethane, propane, butane, LPG, gas oils and light naphthas, catalytic cracking of naphthas and other refinery feedstocks and by conversion of oxygenates, such as methanol, to lower olefins. [0045] For example, the following C4 hydrocarbon mixtures are generally available in any refinery employing steam cracking to produce olefins; a crude
steam cracked butene stream, Raffinate-1 (the product of remaining after solvent extraction or hydrogenation to remove butadiene from the crude steam cracked butene stream) and Raffinate-2 (the product remaining after removal of butadiene and isobutene from the crude steam cracked butene stream). Generally, these streams have compositions within the weight ranges indicated in Table 1 below.
Table 1
[0046] Other refinery mixed C4 streams, such as those obtained by catalytic cracking of naphthas and other refinery feedstocks, typically have the following composition:
Propylene - 0-2 wt%
Propane - 0-2 wt%
Butadiene - 0-5 wt%
Butene- 1 - 5-20 wt%
Butene-2 - 10-50 wt%
Isobutene - 5-25 wt%
Iso-butane - 10-45 wt%
N-butane - 5-25 wt%
[0047] C4 hydrocarbon fractions obtained from the conversion of oxygenates, such as methanol, to lower olefins more typically have the following composition:
Propylene 0-1 wt%
Propane 0-0.5 wt%
Butadiene 0-1 wt%
Butene- 1 10-40 wt%
Butene-2 50-85 wt%
Isobutene 0-10 wt%
N- + iso-butane ■ 0-10 wt%
[0048] Any one or any mixture of the above C4 hydrocarbon mixtures can be used in the process of the invention. In addition to linear butenes and butanes, these mixtures typically contain components, such as isobutene and butadiene, which can be deleterious to the process of the invention. For example, the normal alkylation product of isobutene with benzene is tert-butylbenzene which, as previously stated, acts as an inhibitor to the subsequent oxidation step. Thus, prior to the alkylation step, these mixtures preferably are subjected to butadiene removal and isobutene removal. For example, isobutene can be removed by dimerization or reaction with methanol to produce MTBE, whereas butadiene can be removed by extraction or selective hydro genation to butene-1. [0049] In addition to other hydrocarbon components, commercial C4 hydrocarbon mixtures typically contain other impurities, which could be detrimental to the alkylation process. For example, refinery C4 hydrocarbon streams typically contain nitrogen and sulfur impurities, whereas C4 hydrocarbon streams obtained by oxygenate conversion process typically contain unreacted oxygenates and water. Thus, prior to the alkylation step, these mixtures may also be subjected to one or more of sulfur removal, nitrogen removal and oxygenate removal, in addition to butadiene removal and isobutene removal. Removal of sulfur, nitrogen, oxygenate impurities is conveniently effected by one or a combination of caustic treatment, water washing, distillation, adsorption using molecular sieves and/or membrane separation. Water is also typically removed by adsorption.
[0050] Conveniently, the total feed to the alkylation step of the present invention contains less than 1000 ppm, such as less than 500 ppm, for example less than 100 ppm, water. In addition, the total feed typically contains less than 100 ppm, such as less than 30 ppm, for example less than 3 ppm, sulfur and less than 10 ppm, such as less than 1 ppm, for example less than 0.1 ppm, nitrogen. [0051] The alkylation catalyst used to produce the sec-butyl benzene can comprise any of the molecular sieves listed above for the production of cumene. Preferably the molecular sieve is a member of the MCM-22 family, since these materials are found to be highly selective to the production of sec-butylbenzene. In particular, using an MCM-22 family molecular sieve as the C4 alkylation
catalyst, it is possible to produce sec-butylbenzene that contains less than 0.5 wt%, for example, less than 0.1 wt%, such as less than 0.05 wt%, of isobutylbenzene and tert-butylbenzene.
[0052] The alkylation catalyst can include the molecular sieve in unbound or self-bound form or, alternatively, the molecular sieve can be combined in a conventional manner with an oxide binder, such as alumina, such that the final alkylation catalyst contains between 2 and 80 wt% sieve.
[0053] The alkylation process is conducted such that the organic reactants, i.e., the benzene and the C4 alkylating agent, are brought into contact with the alkylation catalyst in a suitable reaction zone, separate from the cumene alkylation reactor, such as, for example, in a flow reactor containing a fixed bed of the catalyst composition or in a catalytic distillation reactor, under effective alkylation conditions. Such conditions include a temperature of from about 60°C to about 260°C, for example between about 100°C and about 200°C, a pressure of 7000 kPa or less, for example from about 1000 to about 3500 kPa, and a weight hourly space velocity (WHSV) based on C4 alkylating agent of between about 0.1 and about 50 hr"1, for example between about 1 and about 10 hr"1. Typically, the molar ratio of benzene to alkylating agent is from about 1 to about 50, for example from about 2 to about 10.
[0054] The reactants can be in either the vapor phase or partially or completely in the liquid phase and can be neat, i.e., free from intentional admixture or dilution with other material, or they can be brought into contact with the zeolite catalyst composition with the aid of carrier gases or diluents such as, for example, hydrogen or nitrogen.
[0055] Again the alkylation step to produce sec-butylbenzene is highly selective towards monoalkylated species. However, the effluent from the alkylation reaction will normally contain some polyalkylated products, as well as unreacted aromatic feed and the desired sec-butylbenzene. The unreacted aromatic feed can be recycled to the C4 alkylation reactor and, if desired, the polyalkylated can be transalkylated with additional benzene to produce additional sec-butylbenzene. The same catalysts used for the transalkylation of the polyisopropylbenzene products can be used for the polybutylbenzene
transalkylation process. The polybutylbenzene transalkylation reaction is typically conducted under at least partial liquid phase conditions, which suitably include a temperature of 100 to 300°C, a pressure of 1000 to 7000 kPa, a weight hourly space velocity of 1 to 50 hr"1 on total feed, and a benzene/polyalkylated benzene weight ratio of 1 to 10.
Cumene and Sec-Butyl Benzene Oxidation
[0056] The cumene and sec-butylbenzene products of the separate alkylation steps described above are then oxidized to produce the corresponding hydroperoxides. The cumene and sec-butylbenzene can be mixed prior to the oxidation step but, more preferably, they are oxidized in separate reactors since the oxidation rates of cumene and sec-butylbenzene are different. [0057] Whether conducted on a mixture or separately, the oxidation step is accomplished by introducing an oxygen-containing gas, such as air, into a liquid phase containing the cumene and/or sec-butylbenzene. The reaction can be performed in the absence of a catalyst but is slow (of the order of <l%/hour). Improvement in the reaction rate can be achieved by performing the oxidation in the presence of a catalyst, such as a water-soluble chelate compound in which multidentate ligands are coordinated to at least one metal from cobalt, nickel, manganese, copper, and iron. (See U.S. Patent No. 4,013,725). More preferably, a heterogeneous catalyst is used. Suitable heterogeneous catalysts are described in U.S. Patent No. 5,183,945, wherein the catalyst is an oxo (hydroxo) bridged tetranuclear manganese complex and in U.S. Patent No. 5,922,920, wherein the catalyst comprises an oxo (hydroxo) bridged tetranuclear metal complex having a mixed metal core, one metal of the core being a divalent metal selected from Zn, Cu, Fe, Co, Ni, Mn and mixtures thereof and another metal being a trivalent metal selected from In, Fe, Mn, Ga, Al and mixtures thereof. The entire disclosures of said U.S. patents are incorporated herein by reference.
[0058] Other suitable catalysts for the oxidation step are the N-hydroxy substituted cyclic imides described in Published U.S. Patent Application No. 2003/0083527 and incorporated herein by reference, such as N- hydroxyphthalimide, 4-amino-N-hydroxyphthalimide, 3-amino-N-
hydroxyphthalimide, tetrabromo-N-hydroxyphthalimide, tetrachloro-N- hydroxyphthalimide, N-hydroxyhetimide, N-hydroxyhimimide, N- hydroxytrimellitimide, N-hydroxybenzene-l,2,4-tricarboximide, N,N'- dihydroxy(pyromellitic diimide), NjN'-dihydroxyφenzophenone-S^1,^'- tetracarboxylic diimide), N-hydroxymaleimide, pyridine-2,3-dicarboximide, N- hydroxysuccinimide, N-hydroxy(tartaric imide), N-hydroxy-5-norbornene-2,3- dicarboximide, exo-N-hydroxy-7-oxabicyclo[2.2.1 ]hept-5-ene-2,3-dicarboximide, N-hydroxy-cis-cyclohexane- 1 ,2-dicarboximide, N-hydroxy-cis-4-cyclohexene- 1 ,2 dicarboximide, N-hydroxynaphthalimide sodium salt or N-hydroxy-o- benzenedisulphonimide. These materials can be used either alone or in the presence of a free radical initiator and can be used as liquid-phase, homogeneous catalysts or can be supported on a solid carrier to provide a heterogeneous catalyst.
[0059] Suitable conditions for cumene oxidation include a temperature are between about 70°C and about 200°C, such as about 80°C to about 120°C and a pressure of about 50 to about 1000 kPa. Suitable conditions for sec-butylbenzene oxidation include a temperature are between about 70°C and about 200°C, such as about 90°C to about 130°C and a pressure of about 0.5 to about 10 atmospheres (50 to 1000 kPa). Where a mixture of cumene and sec-butylbenzene is oxidized, suitable conditions include a temperature are between about 70°C and about 2000C, such as about 80°C to about 1300C and a pressure of about 50 to about 1000 fcPa.
[0060] A basic buffering agent may be added to the oxidation reaction to combine with acidic by-products that may form during the oxidation. In addition, an aqueous phase may be introduced, which can help dissolve basic compounds, such as sodium carbonate. The per-pass conversion in the oxidation step is preferably kept below 50%, to minimize the formation of byproducts. The oxidation reaction is conveniently conducted in a catalytic distillation unit and the hydroperoxides produced may be concentrated by distilling off the unreacted alkylbenzene prior to the cleavage step.
Hydroperoxide Cleavage
[0061] The cumene and sec-butylbenzene hydroperoxides produced in the oxidation step are subsequently cleaved to produce phenol and acetone, in the case of cumene hydroperoxide cleavage, and phenol and methyl ethyl ketone, in the case of sec-butylbenzene hydroperoxide cleavage. The cleavage reaction can be conducted on a mixture of the hydroperoxides, particularly where the cumene and sec-butylbenzene are mixed prior to the oxidation step, but more preferably the hydroperoxides are cleaved separately.
[0062] The cleavage reaction, whether conducted on a mixture or the separate hydroperoxides, is conveniently carried out in the presence of a catalyst in the liquid phase at a temperature of about 200C to about 150°C, such as about 40°C to about 120°C, a pressure of about 50 to about 7000 kPa, such as about 100 to about 2860 kPa and a liquid hourly space velocity (LHSV) based on the hydroperoxide of about 0.1 to about 100 hr"1, preferably about 1 to about 50 hr"1. The hydroperoxide is preferably diluted in an organic solvent inert to the cleavage reaction, such as methyl ethyl ketone, phenol or sec-butylbenzene, to assist in heat removal. The cleavage reaction is conveniently conducted in a catalytic distillation unit.
[0063] Where the cumene hydroperoxide is cleaved separately, the catalyst employed in the cleavage step can be a homogeneous catalyst but, more preferably, is a heterogeneous catalyst.
[0064] Suitable homogeneous cumene cleavage catalysts include sulfuric acid, perchloric acid, phosphoric acid, hydrochloric acid and p-toluenesulfonic acid. Ferric chloride, boron trifluoride, sulfur dioxide and sulfur trioxide are also effective homogeneous cleavage catalysts. The preferred homogeneous cleavage catalyst is sulfuric acid.
[0065] Suitable heterogeneous catalysts for use in the cleavage of cumene hydroperoxide include solid acid catalysts such as zeolite beta, disclosed in U.S. Patent No. 4,490,565; a Constraint Index 1-12 zeolite, such as ZSM-5, disclosed in U.S. Patent No. 4,490,566; faujasite, disclosed in EP-A-492807; sulfonate- functionalized mesoporous crystalline materials known as M41S materials and disclosed in U.S. Patent No. 6,441,251; smectite clays, described in U.S. Patent
No. 4,870,217; ion exchange resins having sulfonic acid functionality or heteropoly acids, such as 12-tungstophosphoric acid, on an inert support, such as silica, alumina, titania and zirconia, disclosed in U.S. Patent No. 4,898,995. Additional solid-acid catalysts suited for use in the present invention include those comprising a sulfated transition metal oxide, such as sulfated zirconia, together with an oxide of iron or oxides of iron and manganese, as described in U.S. Patent No. 6,169,216, as well as those comprising a mixed oxide of cerium and a Group IVB metal, e.g., zirconium, described in U.S. Patent No. 6,297,406. The entire disclosure of each of the above U.S. patents is incorporated herein by reference. [0066] The cumene hydroperoxide cleavage reaction can also be conducted in the presence of the solid acid catalyst disclosed in U.S. Patent No. 6,169,215 and incorporated herein by reference. Such a catalyst comprises an oxide of a Group IVB metal, such as zirconia or titania, modified with an oxyanion or oxide of a Group VIB metal, such as an oxyanion of chromium, molybdenum or tungsten, by calcination of the oxide species at a temperature of at least 4000C, such as at least 600°C, for example about 700°C to about 7500C. The modification of the Group IVB metal oxide with the oxyanion of the Group VIB metal imparts acid functionality to the material. The catalyst can also contain a metal selected from Groups IB, VIIB, or VIII of the Periodic Table, such as iron, manganese and/or copper.
[0067] Where the sec-butylbenzene hydroperoxide is cleaved separately, the catalyst employed can be a homogeneous catalyst or a heterogeneous catalyst. Suitable homogeneous cleavage catalysts include sulfuric acid, perchloric acid, phosphoric acid, hydrochloric acid and p-toluenesulfonic acid. Ferric chloride, boron trifluoride, sulfur dioxide and sulfur trioxide are also effective homogeneous cleavage catalysts. The preferred homogeneous cleavage catalyst is sulfuric acid. A suitable heterogeneous catalyst for use in the cleavage of sec- butylbenzene hydroperoxide includes a smectite clay, such as an acidic montmorillonite silica-alumina clay, as described in U.S. Patent No. 4,870,217. [0068] For cleavage of a mixture of cumene and sec-butylbenzene hydroperoxides, the catalyst can be a heterogeneous catalyst but more generally is a homogeneous catalyst, such as sulfuric acid.
Bisphenol-A Production
[0069] The products of the cleavage reaction(s) are separated, conveniently by fractionation, into separate phenol, acetone and methyl ethyl ketone streams. The phenol and at least part of the acetone can then be used for production of the desired bisphenol-A, whereas the methyl ethyl ketone can be recovered a saleable product.
[0070] Bisphenol A is produced by the condensation reaction of excess phenol with acetone in the presence of an acidic catalyst. Suitable catalysts include inorganic mineral acids, such as sulfuric acid and hydrogen chloride, and cationic exchange resins, optionally together with a cocatalyst, such as an alkyl mercaptan. [0071] Suitable conditions for the condensation of phenol with acetone to produce bisphenol-A include an acetone/phenol molar ratio in the range of about 1/30 to about 1/3, preferably 1/20 to 1/5, a reaction temperature in the range of about 40°C to about 1500C, preferably about 55°C to about 100°C, and a LHSV (liquid hourly space velocity) of about 0.2 to about 30 hr"1, preferably about 0.5 to about 20 hr"1. The bisphenol-A can then be separated from the condensation product by crystallization.
[0072] The following examples are given for illustrative purposes and do not limit the scope of the invention:
Example 1 : Sec-Butylbenzene synthesis using MCM-22
[0073] A 0.5 gram sample of an MCM-22 catalyst (65 wt% MCM-22/35% alumina binder) was used for the alkylation of benzene with butene-2. The catalyst was in the form of a 1.6mm (1/16") diameter cylindrical extradate and was diluted with sand to 3 cc and loaded into an isothermal, down-flow, fixed- bed, tubular reactor having an outside diameter of 4.76mm (3/16"). The catalyst was dried at 125°C and 1 atm with 100 cc/min flowing nitrogen for 2 hours. The nitrogen was turned off and benzene was fed to the reactor at 60 cc/hr for 1 hour and then reduced to desired WHSV while the reactor pressure was increased to 300 psig (2170 kPa). 2-butene (mixture of cis and trans) was introduced from a syringe pump at a 3:1 benzene/butene molar ratio and the reactor temperature was ramped to 160°C at 5°C/min. Liquid product was collected in a cold-trap and
analyzed off line. Butene conversion was determined by measuring unreacted butene relative to feed butene. Stable operation with 95%+ butene conversion was obtained at butene flow rate of 1.5 WHSV. Catalyst performance at 10 and 13 days on stream are shown in the Table 2.
Example 2: Sec-Butylbenzene synthesis using zeolite beta [0074] The process of Example 1 was repeated but with the MCM-22 catalyst being replaced by 0.5 gm of a zeolite beta catalyst (65 wt% beta/35% alumina binder), again with the catalyst being in the form of a 1.6mm (1/16") diameter cylindrical extrudate. Catalyst performance at 1, 3 and 5 days on stream are shown in the Table 2.
Table 2.
Catalyst MCM-22 Zeolite Beta
Days on Stream 10 13 1 3 . 5
Butene WHSV, h"1 1.5 1.5 2.0 2.0 2.0
2-Butene Conv, % 95.8 96.4 97.5 70.4 48.5
Product Selectivitv, wt% iso- & 1 -Butene 0.049 0.015 0.008 3.353 6.276
C5-C7 0.077 0.064 0.041 0.362 0.345
C8 and C12 (butene
2.199 2.246 1.295 12.883 12.828 oligomers)
Cumene 0.069 0.071 0.073 0.046 0.041 tert-Butylbenzene 0.099 0.098 0.623 0.112 0.108 iso-Butylbenzene* 0.000 0.000 0.000 0.000 0.000 sec-Butylb enzene 90.911 90.812 83.237 74.931 70.144 n-Butylbenzene 0.013 0.013 0.020 0.005 0.007
Di-butylbenzene 6.064 6.105 12.664 4.330 3.355
Tri-butylbenzene 0.261 0.298 1.409 0.036 0.000
Others 0.258 0.276 0.630 3.942 6.895
Sum 100.00 100.00 100.00 100.00 100.00
Butvlbenzene Composition, t-Butylbenzene 0.109 0.108 0.742 0.149 0.153 iso-Butylbenzene* 0.000 0.000 0.000 0.000 0.000 sec-Butylbenzene 99.877 99.877 99.233 99.844 99.837 n-Butylbenzene 0.014 0.014 0.024 0.007 0.010
Sum 100.00 100.00 100.00 100.00 100.00
* Iso-Butylbenzene not measurable (could be obscured by sec- butylbenzene given close elution times).
[0075] Data in Table 2 show that MCM-22 catalyst was highly active and selective for the production of sec-butylbenzene without producing a measurable quantity of iso-butylbenzene and very low quantities of tert-butylbenzene. MCM-22 was also quite stable with no sign of deactivation during the 13-day test cycle. Zeolite beta showed good initial activity. Although it deactivated rapidly as a result of butene oligomer formation, zeolite beta produced sec-butylbenzene without producing measurable quantities of iso-butylbenzene. Zeolite beta produced low quantities of tert-butylbenzene, albeit not as low as MCM-22. When compared at 95+% conversion, MCM-22 was about 8% more selective than zeolite beta for sec-butylbenzene production.
Example 3: Sec-Butylbenzene oxidation
[0076] To a 250-ml round bottom flask fitted with a condenser, stirrer and an air sparger, was charged 75.0 g of sec-butylbenzene (Aldrich). The flask was heated using a temperature-controlled heating mantle. Reaction temperature was 100°C. Reaction pressure was approximately atmospheric. The air flow rate was approximately 175 cc/min. Every 45 minutes, a small aliquot of the reaction mixture was removed from the flask and analyzed by GC. The rate of oxidation of the sec-butylbenzene in the absence of a catalyst was approximately 0.1% per hour.
Example 4: Sec-Butylbenzene oxidation
[0077] To a 250-ml round bottom flask fitted with a condenser, stirrer and an air sparger, was charged 75.0 g of sec-butylbenzene (Aldrich) and 0.1 g of a BaMnO4 catalyst produced according to Preparation 1 of U.S. Patent No. 5,922,920. The flask was heated using a temperature-controlled heating mantle. Reaction temperature was 100°C. Reaction pressure was approximately atmospheric. The air flow rate was approximately 175 cc/min. Every 45 minutes, a small aliquot of the reaction mixture was removed from the flask and analyzed by GC. The rate of oxidation of the sec-butylbenzene in the presence of the
BaMnO4 catalyst was 7 times faster than that of the non-catalyzed oxidation of Example 3.
[0078] While the present invention has been described and illustrated by reference to particular embodiments, those of ordinary skill in the art will appreciate that the invention lends itself to variations not necessarily illustrated herein. For this reason, then, reference should be made solely to the appended claims for purposes of determining the true scope of the present invention.