WO2007143239A2 - Process for producing sec-butylbenzene - Google Patents

Abstract

A process for producing sec-butylbenzene comprises reacting benzene with at least one C4 alkylating agent under alkylation conditions and in the presence of a particulate alkylation catalyst comprising zeolite beta and/or at least one molecular sieve of the MCM-22 family to produce an alkylation product comprising sec-butylbenzene. The alkylation conditions are such that the benzene is at least partially in the liquid phase and the particles of the alkylation catalyst have a surface to volume ratio of at least 80 inch<SUP>-1</SUP>.

Description

PROCESS FOR PRODUCING SEC-BUTYLBENZENE

FIELD

[0001] The present invention relates to a process for producing sec- butylbenzene and for converting the sec-butylbenzene to phenol and methyl ethyl ketone.

BACKGROUND

[0002] Phenol and methyl ethyl ketone are important products in the chemical industry. For example, phenol is useful in the production of phenolic resins, bisphenol A, ε-caprolactam, adipic acid, alkyl phenols, and plasticizers, whereas methyl ethyl ketone can be used as a lacquer, a solvent and for dewaxing of lubricating oils.

[0003] The most common route for the production of methyl ethyl ketone is by dehydrogenation of sec-butyl alcohol (SBA), with the alcohol being produced by the acid-catalyzed hydration of butenes. For example, commercial scale SBA manufacture by reaction of butylene with sulfuric acid has been accomplished for many years via gas/liquid extraction.

[0004] 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. However, the world demand for phenol is growing more rapidly than that for acetone. In addition, the cost of propylene relative to that for butenes is likely to increase, due to a developing shortage of propylene. Thus, a process that uses butenes instead of propylene as feed and coproduces methyl ethyl ketone rather than acetone may be an attractive alternative route to the production of phenol. [0005] It is known that phenol and methyl ethyl ketone can be co-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 113-124 and 261-263 of Process Economics Report No. 22B entitled "Phenol", published by the Stanford Research Institute in December 1977. [0006] Sec-butylbenzene can be produced by alkylating benzene with n- butenes over an acid catalyst. Thus, in our International Patent Publication No. WO 06/15826 we have described an integrated process for producing phenol and methyl ethyl ketone, in which a feed comprising benzene and a C₄ alkylating agent is contacted under liquid phase alkylation conditions with a catalyst comprising zeolite beta or an MCM-22 family molecular sieve to produce an alkylation effluent comprising sec-butylbenzene. The sec-butylbenzene is then oxidized to produce a hydroperoxide and the hydroperoxide is cleaved to produce the desired phenol and methyl ethyl ketone.

[0007] Typically, zeolite catalysts employed in hydrocarbon conversion processes, such as aromatics alkylation, are in the form of cylindrical extrudates. In fact, the zeolite beta and MCM-22 catalysts used in the Examples of WO 06/15826 are in the form of cylindrical extrudates. However, it is known from, for example, 3,966,644 that shaped catalyst particles having a high surface to volume ratio, such as those having a polylobal cross-section, can produce improved results in processes which are diffusion limited, such as the hydrogenation of resid.

[0008] In addition, it is known from U.S. Patent No. 4,441,990 that a polylobal catalyst particle having a non-cylindrical centrally located aperture can reduce the diffusion path for reagents and the pressure drop across packed catalyst beds while minimizing catalyst loss due to breakage, abrasion and crushing. In particular, Example 8 of the '990 patent discloses that hollow trilobal and quadrulobal ZSM-5 catalysts are more active and selective for the ethylation of benzene at 770⁰F and 300 psig pressure than solid cylindrical catalysts of the same length. Under these conditions, the reagents are necessarily in the vapor phase. More recent work has shown that polylobal catalyst particles show little or no advantage when used in the liquid phase ethylation of benzene. [0009] According to the present invention, it has now been found that the activity and monoalkylation selectivity of zeolite beta and MCM-22 family materials in the alkylation of benzene with C₄ alkylating agents can be enhanced by using shaped catalyst particles having a high surface to volume ratio. Moreover, these improvements in activity and mono selectivity are exhibited even under liquid phase alkylation conditions. In addition, it is found that the activity and sec-butylbenzene selectivity are strongly dependent on the zeolite content and mesoporosity of the catalyst.

[0010] US Patent No. 6,888,037 discloses a process for producing cumene by contacting benzene and propylene under at least partial liquid phase alkylating conditions with a particulate molecular sieve alkylation catalyst, wherein the particles of said alkylation catalyst have a surface to volume ratio of about 80 to less than 200 inch^"1.

SUMMARY

[0011] In one aspect, the present invention resides in a process for producing sec-butylbenzene, the process comprising reacting benzene with at least one C₄ alkylating agent under alkylation conditions and in the presence of a particulate alkylation catalyst comprising zeolite beta and/or at least one molecular sieve of the MCM-22 family to produce an alkylation product comprising sec- butylbenzene, wherein the alkylation conditions are such that the benzene is at least partially in the liquid phase and wherein the particles of said alkylation catalyst have a surface to volume ratio of at least 80 inch^"1 and conveniently less than 200 inch^"1.

[0012] Conveniently, the particles of said alkylation catalyst have a surface to volume ratio about 100 inch^"1 to about 150 inch^"1.

[0013] In one embodiment, said catalyst includes at least one molecular sieve of the MCM-22 family. Typically, said at least one molecular sieve of the MCM- 22 family has an X-ray diffraction pattern including d-spacing maxima at 12.4±0.25, 6.9±0.15, 3.57±0.07 and 3.42±0.07 Angstrom. Conveniently, the molecular sieve is selected from MCM-22, PSH-3, SSZ-25, ERB-I, ITQ-I, ITQ-2, MCM-36, MCM-49, MCM-56, UZM-8, and mixtures thereof. [0014] In one embodiment, the process further comprises, prior to said reacting, contacting said catalyst with water under conditions to improve the sec- butylbenzene selectivity of the catalyst. Conveniently, said contacting with water is conducted under conditions including a temperature of at least 0⁰C for a time of at least 0.5 hour, for example a temperature of about 10⁰C to about 50⁰C for a time of about 2 hours to about 24 hours.

[0015] Conveniently, said catalyst comprises about 50 to about 90 wt%, such as about 60 to about 80 wt%, of zeolite beta or said at least one molecular sieve of the MCM-22 family.

[0016] Conveniently, said catalyst has a cumulative pore volume in the 2 to 8 nanometer range, as measured by nitrogen porosimetry, of greater than 0.04 cc/gm, such as greater than 0.07 cc/gm, for example greater than 0.10 cc/gm.

[0017] Conveniently, said C₄ alkylating agent comprises a linear butene, such as butene- 1, butene-2 or a mixture thereof.

[0018] Preferably, said linear butene is added to the process in stages such that said alkylation conditions include an overall molar ratio of benzene to butene from about 1 to about 20, preferably about 2 to aboutlO, more preferably about 3 to about 6.

[0019] Conveniently, said alkylation conditions also include a temperature of from about 60⁰C to about 260⁰C, 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

5O hT ¹.

[0020] In a further aspect, the present invention resides in a process for producing phenol and methyl ethyl ketone, the process comprising:

(a) reacting benzene with at least one linear butene under alkylation conditions such that the benzene is at least partially in the liquid phase and in the presence of a particulate catalyst comprising zeolite beta and/or at least one molecular sieve of the MCM-22 family to produce an alkylation effluent comprising sec-butylbenzene, wherein the particles of said alkylation catalyst have a surface to volume ratio of at least 80 inch^"1 and conveniently less than 200 inch^"1;

(b) oxidizing the sec-butylbenzene from (a) to produce a hydroperoxide; and

(c) cleaving the hydroperoxide from (b) to produce phenol and methyl ethyl ketone. [0021] Conveniently, the oxidizing (b) is conducted in the presence of a catalyst, such as a catalyst selected from (i) an oxo (hydroxo) bridged tetranuclear metal complex comprising manganese, (ii) 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, (iii) an N-hydroxy substituted cyclic imide either alone or in the presence of a free radical initiator, and (iv) N,N',N"-trihydroxyisocyanuric acid either alone or in the presence of a free radical initiator. In one embodiment, the oxidization catalyst is a heterogeneous catalyst.

[0022] Conveniently, the oxidizing (b) is conducted at a temperature of about 70⁰C to about 200⁰C and a pressure of about 0.5 to about 20 atmospheres (50 to 2000 kPa).

[0023] Conveniently, the cleaving (c) is conducted in the presence of a catalyst. The catalyst can be a homogeneous or heterogeneous catalyst. In one embodiment, the catalyst is a homogeneous catalyst, such as sulfuric acid. [0024] Conveniently, the cleaving (c) is conducted at a temperature of about 40⁰C to about 120⁰C, a pressure of about 100 to about 2500 kPa, and a liquid hourly space velocity (LHSV) based on the hydroperoxide of about 0.1 to about 100 hf^l.

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a graph plotting sec-butylbenzene selectivity against cumulative pore volume in the 2-8 nm range for the MCM-49 catalysts of Examples 1 to 5.

[0026] Figure 2 is a graph plotting by-product selectivity against cumulative pore volume in the 2-8 nm range for the MCM-49 catalysts of Examples 1 to 5. [0027] Figure 3 is a graph comparing the sec-butylbenzene selectivity and the dibutylbenzene selectivity of the MCM-49 catalysts of Examples 11 to 14. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0028] The present invention is directed to a process for producing sec- butylbenzene by alkylating benzene with a C₄ alkylating agent in the presence of a particulate catalyst comprising zeolite beta or a zeolite of the MCM-22 family, wherein the catalyst particle is shaped, for example by having a quadrulobe cross- section, such that the catalyst particles have a surface to volume ratio of at least 80 inch^"1 and conveniently less than 200 inch^"1. In particular, it is found that by using such shaped catalyst particles the selectivity of the catalyst to the desired monoalkylated species, sec-butylbenzene, is increased relative to a catalyst with a surface to volume ratio of less than 80 inch^"1, whereas the alkylation activity of the catalyst is increased even more markedly, for example by more than 60% relative to a catalyst with a surface to volume ratio of less than 80 inch^"1. [0029] In addition to catalyst shape, it is found that the amount and type of binder in the catalyst is important in determining the activity and monoalkylation selectivity of the catalyst. In particular, it is found that the catalyst should contain about 50 to about 90 wt%, such as about 60 to about 80 wt%, of zeolite beta or said at least one molecular sieve of the MCM-22 family, with the remainder being a binder, particularly an alumina binder. It is also found that improved sec- butylbenzene selectivity is obtained if the amount and type of binder employed in the alkylation catalyst is such that the catalyst has a cumulative pore volume in the 2 to 8 nanometer range, as measured by nitrogen porosimetry, of greater than 0.04 cc/gm, such as greater than 0.07 cc/gm, for example greater than 0.10 cc/gm.

Benzene Alkylation

[0030] The benzene employed in the alkylation step to produce sec- butylbenzene can be any commercially available benzene feed, but preferably the benzene has a purity level of at least 99 wt%.

[0031] The C₄ alkylating agent comprises at least one linear butene, namely butene-1, butene-2 or a mixture thereof. The alkylating agent can also be an olefinic C₄ hydrocarbon mixture containing linear butenes, such as can be obtained by steam cracking of ethane, propane, butane, LPG and light naphthas, catalytic cracking of naphthas and other refinery feedstocks and by conversion of oxygenates, such as methanol, to lower olefins.

[0032] 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

[0033] 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%

[0034] 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-l wt%

Butene-1 - 10-40 wt%

Butene-2 - 50-85 wt%

Isobutene - 0-10 wt% N- + iso-butane- 0-10 wt%

[0035] Any one or any mixture of the above C₄ hydrocarbon mixtures can be used in the present alkylation process. In addition to linear butenes and butanes, these mixtures typically contain components, such as isobutene and butadiene, which can be deleterious to the alkylation process. 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 selective dimerization or reaction with methanol to produce MTBE, whereas butadiene can be removed by extraction or selective hydrogenation to butene-1. Preferably, the C₄ alkylating agent employed in the present process contains less than 1 wt% iso-butene and less than 0.1 wt% butadiene.

[0036] 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.

[0037] Conveniently, the total feed to the alkylation step of the present process 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. [0038] Although not preferred, it is also possible to employ a mixture of a C₄ alkylating agent, as described above, and C₃ alkylating agent, such as propylene, as the alkylating agent in the present alkylation process so that the alkylation step produces a mixture of cumene and sec-butylbenzene. The resultant mixture can then be processed through oxidation and cleavage, to make a mixture of acetone and MEK, along with phenol, preferably where the molar ratio of acetone to phenol is 0.5:1, to match the demand for bisphenol-A production. [0039] The alkylation catalyst used in the present process is a crystalline molecular sieve of the MCM-22 family. The term "MCM-22 family material" (or "material of the MCM-22 family" or "molecular sieve of the MCM-22 family" or "MCM-22 family zeolite"), as used herein, includes one or more of:

• molecular sieves made from a common first degree crystalline building block unit cell, which unit cell has the MWW framework topology. (A unit cell is a spatial arrangement of atoms which if tiled in three-dimensional space describes the crystal structure. Such crystal structures are discussed in the "Atlas of Zeolite Framework Types", Fifth edition, 2001, the entire content of which is incorporated as reference);

• molecular sieves made from a common second degree building block, being a 2-dimensional tiling of such MWW framework topology unit cells, forming a monolayer of one unit cell thickness, preferably one c-unit cell thickness;

• molecular sieves made from common second degree building blocks, being layers of one or more than one unit cell thickness, wherein the layer of more than one unit cell thickness is made from stacking, packing, or binding at least two monolayers of one unit cell thickness. The stacking of such second degree building blocks can be in a regular fashion, an irregular fashion, a random fashion, or any combination thereof; and

• molecular sieves made by any regular or random 2-dimensional or 3- dimensional combination of unit cells having the MWW framework topology. [0040] Molecular sieves of the MCM-22 family include those molecular sieves having an X-ray diffraction pattern including d-spacing maxima at 12.4±0.25, 6.9±0.15, 3.57±0.07 and 3.42+0.07 Angstrom. The X-ray diffraction data used to characterize the material are obtained by standard techniques using the K-alpha doublet of copper as incident radiation and a diffractometer equipped with a scintillation counter and associated computer as the collection system. [0041] Materials 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. Molecular sieves of the MCM-22 family are preferred as the alkylation catalyst since they have been found to be highly selective to the production of sec-butylbenzene, as compared with the other butylbenzene isomers. Preferably, the molecular sieve is selected from (a) MCM- 49, (b) MCM-56 and (c) isotypes of MCM-49 and MCM-56, such as ITQ-2. [0042] The alkylation catalyst can include the molecular sieve in unbound or self-bound form or, more preferably, the molecular sieve can be combined in a conventional manner with an oxide binder, preferably alumina, such that the final alkylation catalyst contains between about 50 and about 90 wt%, for example between about 60 and about 80 wt%, of the molecular sieve, with the remainder being the binder. Typically, the amount and type of the binder is selected such that the catalyst has a cumulative pore volume in the 2 to 8 nanometer range, as measured by nitrogen porosimetry, of greater than 0.04 cc/gm, such as greater than 0.07 cc/gm, for example greater than 0.10 cc/gm.

[0043] The alkylation catalyst employed in the present process is formulated, generally by extrusion, into particles having a surface to volume ratio of at least 80 inch^{" 1} and conveniently less than 200 inch^"1, such as from about 100 inch^"1 to about 150 inch^{" 1}. This can readily be achieved by controlling the particle size of the catalyst or by using a shaped catalyst particle, such as the grooved cylindrical extrudate described in U.S. Patent No. 4,328,130 or a hollow or solid polylobal extrudate as described in U.S. Patent No. 4,441,990, the entire contents of both of which are incorporated herein by reference. For example, a cylindrical catalyst particle having a diameter of 1/32 inch (0.8 mm) and a length of 3/32 inch (2.4 mm) has a surface to volume ratio of 141, whereas a quadrulobal solid extrudate having the external shape disclosed in Figure 4 of U.S. Patent No. 4,441,990 and having a maximum cross-sectional dimension of 1/16 inch (1.6 mm) and a length of 3/16 inch (4.8 mm) has a surface to volume ratio of 128. A hollow tubular extrudate having an external diameter of 1/10 inch (2.5 mm), an internal diameter of 1/30 inch (0.8 mm) and a length of 3/10 inch (7.6 mm) has a surface to volume ratio of 136.

[0044] Prior to use in the present alkylation process, the MCM-22 family catalyst, either in bound or unbound form, may be contacted with water, either in liquid or vapor form, under conditions to improve its sec-butylbenzene selectivity. Although the conditions of the water contacting are not closely controlled, improvement in sec-butylbenzene selectivity can generally be achieved by contacting the zeolite with water at temperature of at least 0⁰C, such as from about 1O⁰C to about 50⁰C, for a time of at least 0.5 hour, for example for a time of about 2 hours to about 24 hours. Typically, the water contacting is conducted so as to increase the weight of the catalyst by 30 to 75 wt% based on the initial weight of the zeolite.

[0045] Although the reason for the improved selectivity is not fully understood, it is believed that the water contacting promotes re-insertion of Al into the tetrahedral framework of the zeolite and/or a relaxation of the local geometric strains that are induced by earlier steps in the zeolite production, particularly calcination and/or dehydration. As a result, the water contacting seems to be accompanied by increases in the amplitude or width of at least one of the peaks in the ²⁹Si MAS NMR spectrum of the zeolite in the chemical shift range of -80 to -120 ppm from tetramethylsilane (TMS). In particular, the water contacting frequently seems to improve the resolution of a peak in the -90 to -100 ppm chemical shift range of ²⁹Si MAS NMR spectrum of the zeolite, which peak is not present or is unresolved in the zeolite without water treatment. In this respect all references in the present specification to NMR chemical shift values are determined based on the shift from the reference peak for tetramethylsilane (TMS).

[0046] After water treatment, the MCM-22 family zeolite may be used directly as an alkylation catalyst for the production of sec-butylbenzene. Alternatively, after being contacted with water and prior to use as an alkylation catalyst, the zeolite can be dried in air or an inert gas, such as nitrogen, such as at a temperature of about 100⁰C to about 200⁰C for a time of about 1 hour to about 5 hours. Surprisingly, it is found that this drying step does not significantly detract from the improvement in sec-butylbenzene selectivity produced by the water contacting step.

[0047] The alkylation process is conducted such that the organic reactants, i.e., the alkylatable aromatic compound and the alkylating agent, are brought into contact with the alkylation catalyst described above under effective alkylation conditions controlled so as to maximize the conversion to sec-butylbenzene and minimize the formation of butene oligomers. In particular, a large stoichiometric excess of benzene is fed to the alkylation reaction and the local concentration of the alkylating agent is reduced preferably by staged addition of the alkylating agent. This is conveniently achieved by providing the alkylation catalyst in a plurality of fixed bed reaction zones connected in series. Most or all of the benzene is then fed to the first reaction zone, whereas the alkylating agent is divided into a plurality of equal or different aliquot portions, each of which is fed to a different reaction zone. Alternatively, the alkylation reaction can be conducted in a catalytic distillation reactor, with the alkylating agent being fed to the reactor continuously or in stages over the course of the reaction. In either case, the total amounts of benzene and alkylating agent fed to reaction should be such that the overall molar ratio of benzene to alkylating agent is from about 1 to about 20, preferably about 3 to about 10, more preferably about 4 to about 9. [0048] In addition, the alkylation conditions conveniently include a temperature of from about 6O⁰C to about 260⁰C, for example between about 100⁰C and about 200⁰C, 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. In particular, the alkylation conditions are selected so that benzene is at least partially in the liquid phase.

[0049] Using the catalyst and alkylation conditions described above, it is found that the alkylation step of the process of the invention is highly selective to sec-butylbenzene. In particular, it is found that the alkylation product generally comprises at least 93 wt%, preferably at least 95 wt%, sec-butylbenzene, between about 0.01 wt% and about 1 wt%, preferably between about 0.05 wt% and about 0.8 wt% of butene oligomers, and less than 0.5 wt% of isobutylbenzene. [0050] Although the alkylation step is highly selective towards sec- butylbenzene, 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 alkylation reactor. The bottoms from the benzene distillation are further distilled to separate monoalkylated 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. [0051] Transalkylation with additional benzene is typically effected in a transalkylation reactor, separate from the alkylation reactor, over a suitable transalkylation catalyst, such as a molecular sieve of the MCM-22 family, zeolite beta, MCM-68 (see U.S. Patent No. 6,014,018), zeolite Y and mordenite. 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. The transalkylation reaction is typically conducted under at least partial liquid phase conditions, which suitably include a temperature of 100 to 300⁰C, a pressure of 1000 to 7000 kPa, a weight hourly ssppaaccee vveelloocciittyy ooff 11 ttoo .50 hr^"1 on total feed, and a benzene/polyalkylated benzene weight ratio of 1 to 10.

Sec-Butyl Benzene Oxidation

[0052] In order to convert the sec-butylbenzene into phenol and methyl ethyl ketone, the sec-butylbenzene is initially oxidized to the corresponding hydroperoxide. This is accomplished by introducing an oxygen-containing gas, such as air, into a liquid phase containing the sec-butylbenzene. Unlike cumene, atmospheric air oxidation of sec-butylbenzene in the absence of a catalyst is very difficult to achieve. For example, at 110⁰C and at atmospheric pressure, sec- butylbenzene is not oxidized, while cumene oxidizes very well under the same conditions. At higher temperature, the rate of atmospheric air oxidation of sec- butylbenzene improves; however, higher temperatures also produce significant levels of undesired by-products.

[0053] Improvements in the reaction rate and selectivity can be achieved by performing sec-butylbenzene oxidation in the presence of a catalyst. Suitable sec- butylbenzene catalysts include 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.

[0054] Other suitable catalysts for the sec-butylbenzene oxidation step are the N-hydroxy substituted cyclic imides described in U.S. Patent No. 6,720,462 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- 1 ,2,4- tricarboximide, N,N'-dihydroxy(pyromellitic diimide), N,N'- dihydroxy(benzophenone-3,3',4,4'-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-l,2-dicarboximide, N- hydroxy-cis-4-cyclohexene-l,2 dicarboximide, N-hydroxynaphthalimide sodium salt or N-hydroxy-o-benzenedisulphonimide. Preferably, the catalyst is N- hydroxyphthalimide. Another suitable catalyst is N,N',N"-thihydroxyisocyanuric acid.

[0055] 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. [0056] Suitable conditions for the sec-butylbenzene oxidation step include a temperature of about 70⁰C to about 200⁰C, such as about 90⁰C to about 130⁰C, and a pressure of about 0.5 to about 20 atmospheres (50 to 2000 kPa). A basic buffering agent may be added to react with acidic by-products that may form during the oxidation, hi addition, an aqueous phase may be introduced to help dissolve basic compounds, such as sodium carbonate. The per-pass conversion in the oxidation step is preferably kept below 50%, to minimize formation of byproducts. The oxidation reaction is conveniently conducted in a catalytic distillation unit and the sec-butylbenzene hydroperoxide produced may be concentrated by distilling off unreacted sec-butylbenzene prior to the cleavage step.

Hydroperoxide Cleavage

[0057] The final step in the conversion of the sec-butylbenzene into phenol and methyl ethyl ketone involves cleavage of the sec-butylbenzene hydroperoxide, which is conveniently effected by contacting the hydroperoxide with a catalyst in the liquid phase at a temperature of about 20⁰C to about 15O⁰C, such as about 4O⁰C to about 12O⁰C, a pressure of about 50 to about 2500 kPa, such as about 100 to about 1000 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 sec-butylbenzene 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.

[0058] The catalyst employed in the cleavage step 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, the entire disclosure of which is incorporated herein by reference.

[0059] The following Examples are given for illustrative purposes and do not limit the scope of the invention. In the Examples, catalyst performance is defined by reference to the kinetic rate constant which is determined by assuming first- order reaction kinetics. For a discussion of the determination of the kinetic rate constant, reference is directed to "Heterogeneous Reactions: Analysis, Examples, and Reactor Design, Vol. 2: Fluid-Fluid-Solid Reactions" by L. K. Doraiswamy and M. M. Sharma, John Wiley & Sons, New York (1994) and to "Chemical Reaction Engineering" by O. Levenspiel, Wiley Eastern Limited, New Delhi (1972).

Example 1

Sec-butylbenzene production with 65% MCM-22/35% alumina cylindrical extrudate

[0060] A sample of fresh MCM-22 catalyst, with a nominal composition of 65% MCM-22 crystal and 35% Versal 300 alumina as binder, was extruded into 1/16 inch (1.6 mm) diameter cylindrical form. This extrudate was then pre- calcined in nitrogen at 510⁰C. ammonium exchanged with ammonium nitrate to remove sodium, and calcined in air-nitrogen mixture at 538⁰C. The extrudate was cut to 1/16 inch (1.6 mm) length. The resultant sized catalyst had a surface to volume ratio of 72 inch^"1.

[0061] One gram of the sized catalyst was used for alkylation of benzene with 2-butene in a fixed-bed reactor. The catalyst was diluted with sand to 3 cc and loaded into an isothermal, down-flow, fixed-bed, tubular reactor having an outside diameter of 4.76 mm (3/16"). The catalyst was dried for 2 hours at 150⁰C and 1 atm with 100 cc/min flowing nitrogen. Nitrogen was turned off and benzene was fed to the reactor at 60 cc/hr until reactor pressure reached 300 psig (2170 kPa). Benzene flow was then reduced to 7.63 cc/hr and temperature was adjusted to 16O⁰C. 2-Butene feed (40.04% cis-butene, 59.24% trans-butene, 0.39% n-butane, 0.15% isobutene and 1-butene, and 0.18% others) was introduced from a syringe pump at 2.57 cc/hr or 1.6 WHSV. Feed benzene/butene molar ratio was 3:1. Liquid products were collected in a cold-trap and analyzed off line. Butene conversion was determined by measuring unreacted butene relative to feed butene. Data were collected at 1.6, 4.8, 7.2, then 1.6 WHSV on butene at 160⁰C, 300 psig (2170 kPa), and 3:1 benzene/butene molar ratio. The first-order rate constant based on butene conversion and total catalyst weight was 14.6 hr^"1. Representative data at 95% and 97% butene conversions after lineout are shown in Table 2.

Example 2

Sec-butylbenzene production with 65% MCM-22/35% alumina quadrulobe extrudate

[0062] A sample of fresh MCM-22 catalyst, with a nominal composition of 65% MCM-22 crystal and 35% Versal 300 alumina as binder, was extruded into 1/20 inch (1.3 mm) diameter quadrulobe form. This extrudate was then pre- calcined in nitrogen at 510⁰C, ammonium exchanged with ammonium nitrate to remove sodium, and calcined in air-nitrogen mixture at 538°C. The extrudate was cut to 1/16 inch (1.6 mm) length. The resultant sized catalyst had a surface to volume ratio of 120 inch^{" 1}. A 0.4 g sample of the sized catalyst was used for alkylation of benzene with 2-butene in a fixed-bed reactor. The same startup procedure described in Example 1 was followed. Data were collected at 4, 12, and 4 WHSV on butene at 160⁰C, 300 psig (2170 kPa), and 3: 1 benzene/butene molar ratio. First-order rate constant based on butene conversion and total catalyst weight was 24.7 hr^"1 for this catalyst. Representative data at 95% butene conversions after lineout are shown in Table 2.

Table 2

All samples were collected at 160°C, 300 psig, and 3:1 benzene/butene molar ratio. ^: Iso-Butylbenzene less than 0.5% in total butylbenzene was not detectable with GC used.

[0063] As shown in Table 2, when compared to the 1/16" cylindrical extrudate prepared under otherwise identical conditions, the 1/20" quadrulobe catalyst provided 68% higher activity as show by the first-order rate constants. The 1/20" quadrulobe catalyst also exhibited improved sec-butylbenzene selectivity and reduced di- and tributylbenzene make. Example 3

Sec-butylbenzene production with 20%MCM-49/80%V300 quadrulobe extrudate

[0064] A sample of fresh MCM-49 catalyst, with a nominal composition of 20 wt% zeolite and 80 wt% Versal 300 (V300) alumina, was extruded to 1/20 inch (1.3 mm) diameter quadrulobe form and was cut to lengths of 1/20 inch (1.3 mm). The resultant sized catalyst had a surface to volume ratio of 120 inch^"1. A 0.8 g aliquot of this sized MCM-49 catalyst was used for alkylation of benzene with 2- butene in a fixed-bed reactor. The catalyst was diluted with sand to 3 cc and loaded into an isothermal, down-flow, fixed-bed, tubular reactor having an outside diameter of 4.76 mm (3/16"). The catalyst was dried for 2 hours at 150⁰C and 1 atm with 100 cc/min flowing nitrogen. Nitrogen was turned off and benzene was fed to the reactor at 60 cc/hr until reactor pressure reached 300 psig (2170 kPa). Benzene flow was then reduced to 7.63 cc/hr and temperature was adjusted to 16O⁰C. 2-Butene feed (48.66% cis-butene, 51.07% trans-butene, 0.05% n-butane, 0.21% isobutene and 1-butene, and 0.01% others) was introduced from a syringe pump at 2.57 cc/hr or 2.0 WHSV. Feed benzene/butene molar ratio was 3:1. Liquid products were collected in a cold-trap and analyzed off line. Butene conversion was determined by measuring unreacted butene relative to feed butene. Data were collected at 2.0 then 6.0 WHSV on butene at 160⁰C, 300 psig (2170 kPa), and 3:1 benzene/butene molar ratio. First-order rate constant based on butene conversion and total catalyst weight was 6.4 hr^"1 for this catalyst. Representative data at 94% butene conversions are shown in Table 3.

Example 4

Sec-butylbenzene production with 40%MCM-49/60%V300 quadrulobe extrudate

[0065] A sample of fresh MCM-49 catalyst, with a nominal composition of 40 wt% zeolite and 60 wt% Versal 300 (V300) alumina, was extruded to 1/20 inch (1.3 mm) diameter quadrulobe form and was cut to lengths of 1/20 inch (1.3 mm). The resultant sized catalyst had a surface to volume ratio of 120 inch^"1. A 0.4 g aliquot of this sized MCM-49 catalyst was used for alkylation of benzene with 2- butene in a fixed-bed reactor. The same startup procedure described in Example 3 was followed. Data were collected at 4.0 then 8.0 WHSV on butene at 160°C, 300 psig (2170 kPa), and 3:1 benzene/butene molar ratio. First-order rate constant based on butene conversion and total catalyst weight was 15.0 hr ¹ for this catalyst. Representative data at 93% butene conversions are shown in Table 3.

Example 5

Sec-butylbenzene production with 60%MCM-49/40%V300 quadrulobe extrudate

[0066] A sample of fresh MCM-49 catalyst, with a nominal composition of 60 wt% zeolite and 40 wt% Versal 300 (V300) alumina, was extruded to 1/20 inch (1.3 mm) diameter quadrulobe form and was cut to lengths of 1/20 inch (1.3 mm). The resultant sized catalyst had a surface to volume ratio of 120 inch^"1. A 0.4 g aliquot of this sized MCM-49 catalyst was used for alkylation of benzene with 2- butene in a fixed-bed reactor. The same startup procedure described in Example 3 was followed. Data were collected at 4.0 then 8.0 WHSV on butene at 160⁰C, 300 psig (2170 kPa), and 3:1 benzene/butene molar ratio. First-order rate constant based on butene conversion and total catalyst weight was 36.8 hr^"1 for this catalyst. Representative data at 94% butene conversions are shown in Table 3.

Example 6

Sec-butylbenzene production with 80%MCM-49/20%V300 quadrulobe extrudate

[0067] A sample of fresh MCM-49 catalyst, with a nominal composition of 80 wt% zeolite and 20 wt% Versal 300 (V300) alumina, was extruded to 1/20 inch (1.3 mm) diameter quadrulobe form and was cut to lengths of 1/20 inch (1.3 mm). The resultant sized catalyst had a surface to volume ratio of 120 inch^"1. A 0.38 g aliquot of this sized MCM-49 catalyst was used for alkylation of benzene with 2- butene in a fixed-bed reactor. The same startup procedure described in Example 3 was followed. Data were collected at 4.2, 14.4, 25.2, then 4.2 WHSV on butene at 160⁰C, 300 psig (2170 kPa), and 3:1 benzene/butene molar ratio. First-order rate constant based on butene conversion and total catalyst weight was 45.7 hr^"1 for this catalyst. Representative data at 97% butene conversions are shown in Table 3. Example 7

Sec-butylbenzene production with 100% MCM-49 quadrulobe extrudate

[0068] A sample of fresh MCM-49 catalyst, composed of 100% MCM-49 crystal, was extruded to 1/20 inch (1.3 mm) diameter quadrulobe form and was cut to lengths of 1/20 inch (1.3 mm). The resultant sized catalyst had a surface to volume ratio of 120 inch^"1. A 0.2 g aliquot of this sized MCM-49 catalyst was used for alkylation of benzene with 2-butene in a fixed-bed reactor. The same startup procedure described in Example 3 was followed. Data were collected at 8.0 then 24.0 WHSV on butene at 160⁰C, 300 psig (2170 kPa), and 3:1 benzene/butene molar ratio. First-order rate constant based on butene conversion and total catalyst weight was 50.3 hr^"1 for this catalyst. Representative data at 97% butene conversions are shown in Table 3.

Table 3

Example 3 4 5 6 7

% of MCM-49 20 40 60 80 100

Days on Stream 1 8 2 8 5 8 6 8 69

Benzene WHSV 8 3 16 7 16 7 17 4 33 3

Butene WHSV 2 0 4 0 4 0 4 2 8 0

Butene Conversion, % 944 94 30 974 967 97 1

Product Selectivity, wt % l-Butane 0000 0032 0002 0001 0002 n-Butane 0000 0022 0000 0000 0000

C₅-C₇ 0 112 0 100 0 11 1 0093 0073

C₈= 2 243 1 589 1 112 0 690 0 518

Cg-H 0042 0051 0048 0054 0096 + C₁₀-Cn Arom 0076 0 100 0 142 0 130 0 168

Cl3"₁5 0035 0058 0 113 0 101 0 186

Cumene 0021 0023 0039 0030 0000 t-BB 0011 0021 0071 0065 0 103 l-BB * 0000 0000 0000 0000 0000 s-BB 93 637 93 933 94247 92 183 87 628 n-BB 0019 0016 0016 001 1 0000

DiBB 3 697 3 936 3 910 6027 10434

TnBB 0 102 0089 0 179 0426 0781

Heavies 0005 0028 0009 0 188 0013

Sum 1000 1000 1000 1000 1000 s-Butylbenzene (BB)

Purity, t-BB/all BB, % 0011 0023 0076 0071 0 1 17 i-BB*/all BB, % 0000 0000 0000 0000 0000 s-BB/all BB, % 99 968 99 960 99 907 99917 99 883 n-BB/all BB, % 0020 0017 0017 0012 0000

Sum, % 1000 1000 1000 1000 1000

Di-BB/s-BB Wt Ratio, % 3 9 4 1 4 1 6 5 12 1

1 st-order rate constant, hr ¹ 6 4 15 0 36 8 45 7 503

Mesoporosity, cc/g

(cumulative pore volume 0 29 0 28 0 18 0 12 003 in 2-8 nm range)

All samples collected at 160⁰C 300 psig and 3 I benzene/butene molar ratio iso Butylbenzene less than 0 5% in total butylbenzene is not detectable with GC employed

[0069] Referring to Table 3, which compares catalyst performance for s-BB production at steady-state operation, it will be seen that the catalysts with 20%, 40%, and 60% MCM-49 (Examples 3-5) achieved 94% s-BB selectivity at 94+% butene conversion and their dibutylbenzene (DiBB) production level was below 4%. However, catalyst activity expressed as the first-order rate constant dropped significantly as MCM-49 content decreased, especially for the 20% and 40% MCM-49 samples. In addition, the production of butene dimers (shown as Cs=) increased as MCM-49 content decreased. Moreover, in the case of the 100% MCM-49 extrudate (Example 7), although the catalyst activity was high, the s-BB selectivity decreased to less than 88%.

[0070] Catalyst cumulative pore volume data in the 2-8 nm range (meso pore range) obtained from N₂ porosimetry are also shown at the bottom of Table 3. Similarly, Figure 1 plots s-BB selectivity vs. the cumulative pore volume in the 2- 8 nm range and Figure 2 plots byproduct selectivity vs. the cumulative pore volume in the 2-8 nm range. From these results it will be seen that catalysts with 20%, 40%, and 60% MCM-49 had sufficient alumina binder and high mesoporosity (0.18 - 0.29 cc/g) and achieved 94% s-BB selectivity with DiBB level below 4%. The 80% MCM-49 catalyst had reduced content of alumina binder and reduced mesoporosity range (0.12 cc/g) achieved reduced s-BB selectivity of 92% and increased DiBB selectivity of 6%. The 100% MCM-49 with no alumina binder and limited mesoporosity (0.04 cc/g) had poor performance with 88% s-BB selectivity and 10% DiBB selectivity. [0071] The above results suggest that the 20%, 40% and 100% MCM-49 formulations are less preferred for s-BB production. In addition, the data show that high binder mesoporosity is important for MCM-49 catalysts to achieve high s-BB selectivity. Thus, preferred catalyst formulation for MCM-49 type catalysts can be obtained by using binders, such as alumina, characterized by the presence of sufficient mesoporosity. Such binders would provide mesoporosity higher than 0.04 cc/g as measured by N₂ porosimetry.

Example 8

Sec-butylbenzene production with humidified 60%MCM-49/40%V300 quadrulobe extrudate

[0072] The catalyst described in Example 5 was humidified at room temperature with 100% humidity. A 0.40 g sample of the catalyst (cut to 1/20 inch length as well) was weighed into a sample tray. The tray with the catalyst was placed on a holding-tray inside a desiccator, which contained water at bottom. There was no direct contact between the catalyst and liquid water. The catalyst was left in the closed desiccator overnight. The final weight of the catalyst was 0.65 g. The entire amount was loaded to the reactor with the same procedure described in Example 1. The catalyst was used without drying. Benzene was fed to the reactor at 60 cc/hr until reactor pressure reached 300 psig (2170 kPa) and reactor temperature reached 160⁰C (ramped at 5°C/min). Benzene flow was then reduced to 7.63 cc/hr. The same 2-butene feed was introduced at 2.57 cc/hr or 4 WHSV. Feed benzene/butene molar ratio was maintained at 3:1 for the entire run. Data were collected at 4, 12, 26, then 4 WHSV on butene at 160⁰C, 300 psig (2170 kPa), and 3:1 benzene/butene molar ratio. Representative data at 97% butene conversion after lineout are shown in Table 4.

Example 9

Sec-butylbenzene production with humidified 80%MCM-49/20%V300 quadrulobe extrudate

[0073] The humidification and testing procedure of Example 8 was followed using catalyst described in Example 6. Data were collected at 4.2, 12.6, 25.2, then 4.2 WHSV on butene at 160°C, 300 psig (2170 kPa), and 3:1 benzene/butene molar ratio. Representative data at 97% butene conversion after lineout are shown in Table 4.

Example 10

Sec-butylbenzene production with humidified 100%MCM-49 quadrulobe extrudate

[0074] The humidification and testing procedure of Example 8 was followed using catalysts described in Example 7. Data were collected at 8, 24, then 36 WHSV on butene at 160⁰C, 300 psig (2170 kPa), and 3:1 benzene/butene molar ratio. Representative data at 91% butene conversion are shown in Table 4. Table 4

Example 8 9 10

% of MCM-49 60 80 100

Days on Stream 6.8 10.8 9.9

Benzene WHSV 16.6 17.5 33.3

Butene WHSV 4.0 4.2 8.0

Butene Conversion, % 96.8 96.5 91.2

Product Selectivity, wt % i-Butane 0.001 0.001 0.001 n-Butane 0.000 0.000 0.070

C₅-C₇ 0.091 0.079 0.093

C₈= 0.759 0.501 1.273

C]₃-_I5 0.071 0.130 0.219

Cumene 0.025 0.035 0.001 t-BB 0.048 0.084 0.083 i-BB * 0.000 0.000 0.000 s-BB 94.432 94.493 86.503 n-BB 0.008 0.008 0.004

DiBB 4.095 4.271 10.762

TriBB 0.228 0.251 0.784

Heavies 0.116 0.009 0.010

Sum 100.0 100.0 100.1 s-Butvlbenzene (BB)

Purity, t-BB/all BB, % 0.051 0.088 0.096 i-BB*/all BB, % 0.000 0.000 0.000 s-BB/all BB, % 99.941 99.903 99.899 n-BB/all BB, % 0.008 0.008 0.005

Sum, % 100.0 100.0 100.0

Di-BB/s-BB Wt Ratio, % 4.3 4.5 12.4

1 st-order rate constant, hr^"1 53.2 48.9 36.8

All samples collected at 16O⁰C, 300 psig, and 3: 1 benzene/butene molar ratio. ^: iso-Butylbenzene less than 0.5% in total butylbenzene is not detectable with GC used.

[0075] Referring to Table 4, it will be seen that the catalyst with 60% MCM- 49 (Example 8) showed a significant improvement in activity but no improvement in s-BB selectivity after humidification. This indicates that s-BB selectivity for this sample was at or near its peak level with or without catalyst humidification. The catalyst with 80% MCM-49 (Example 9) showed a slight improvement in activity and 2.3% net improvement in s-BB selectivity (94.5% vs. 92.2%) after humidification. This indicates that humidification improved s-BB selectivity to or near its peak value for the 80% sample. In contrast, the catalyst with 100% MCM-49 (Example 9) showed no improvement in activity or s-BB selectivity, hi fact, catalyst activity expressed as first-order rate constant decreased after humidification, and s-BB selectivity remained at the 87% level.

Example 11

Sec-butylbenzene production with humidified 80 %MCM-49/20% alumina quadrulobe extrudate

[0076] A further 0.38 g sample of the sized catalyst from Example 6 was humidified overnight at room temperature with 100% humidity using water. The catalyst was weighed into a sample tray. The tray with the catalyst was placed on a holding-tray inside a desiccator which contained water at bottom. There was no direct contact between the catalyst and liquid water. The catalyst was left in the closed desiccator overnight. The final weight of the catalyst was 0.50 g. The entire amount was loaded into the reactor using the same procedure described in Example 1. The catalyst was used without drying. Benzene was fed to the reactor at 60 cc/hr until the reactor pressure reached 300 psig (2170 kPa) and the reactor temperature reached 160⁰C (ramped at 5°C/min). Benzene flow was then reduced to 7.63 cc/hr. The same 2-butene feed used in Example 1 was introduced at 2.57 cc/hr or 4.2 WHSV. Data were collected at 4.2, 12.6, 25.2, then 4.2 WHSV on butene at 160⁰C, 300 psig (2170 kPa), and 3:1 benzene/butene molar ratio. First- order rate constant based on butene conversion and total catalyst weight was 48.9 hr^"1 for this catalyst. Representative data at 97% butene conversions after lineout are shown in Table 5.

Example 12

Sec-butylbenzene production with humidified 80% MCM-49/20% silica quadrulobe extrudate

[0077] A fresh MCM-49 catalyst with a nominal composition of 80% MCM- 49 crystal and 20% silica as binder was extruded with silica into 1/20 inch quadrulobe form. This extrudate was then pre-calcined in nitrogen at 51O⁰C, ammonium exchanged with ammonium nitrate to remove sodium, and calcined in air-nitrogen mixture at 538°C. The extrudate was cut to 1/20 inch length. A 0.20 g of the sized catalyst was humidified overnight at room temperature with 100% humidity using water. The final weight of the catalyst was 0.28 g. The entire amount was loaded to the reactor with the same procedure described in Example 1. The same startup procedure described in Example 11 was followed. Data were collected at 8, 24, then 48 WHSV on butene at 16O⁰C, 300 psig (2170 kPa), and 3:1 benzene/butene molar ratio. First-order rate constant based on butene conversion and total catalyst weight was 45.6 hr^"1 for this catalyst. Representative data at 95% butene conversion after lineout are shown in Table 5.

Example 13

Sec-butylbenzene production with humidified 80% MCM-49/20% titania quadrulobe extrudate

[0078] A fresh MCM-49 catalyst with a nominal composition of 80% MCM- 49 crystal and 20% P25 titania as binder was extruded into 1/20 inch quadrulobe form. This extrudate was then pre-calcined in nitrogen at 510⁰C, ammonium exchanged with ammonium nitrate to remove sodium, and calcined in air-nitrogen mixture at 538°C. The extrudate was cut to 1/20 inch length. A 0.20 g of the sized catalyst was humidified overnight at room temperature with 100% humidity using water. The final weight of the catalyst was 0.26 g. The entire amount was loaded to the reactor with the same procedure described in Example 1. The same startup procedure described in Example 11 was followed. Data were collected at 8, 24, 48, then 8 WHSV on butene at 160⁰C, 300 psig (2170 kPa), and 3:1 benzene/butene molar ratio. First-order rate constant based on butene conversion and total catalyst weight was 50.7 hr^"1 for this catalyst. Representative data at 93% butene conversions after lineout are shown in Table 5.

Example 14

Sec-butylbenzene production with humidified 100% MCM-49 quadrulobe extrudate

[0079] The same catalyst described in Example 7 was used and the extrudate was cut to 1/20 inch length. A 0.20 g of the sized catalyst was humidified overnight at room temperature with 100% humidity using water. The final weight of the catalyst was 0.26 g. The entire amount was loaded to the reactor with the same procedure described in Example 1. The same startup procedure described in Example 11 was followed. Data were collected at 8, 24, then 8 WHSV on butene at 160⁰C, 300 psig (2170 kPa), and 3:1 benzene/butene molar ratio. First-order rate constant based on butene conversion and total catalyst weight was 36.8 hr^"1 for this catalyst. Representative data at 93% butene conversions are shown in Table 5.

Table 5

Example 1 1 12 13 14

80/20 MCM- 80/20 MCM- 80/20MCM- 100%

Catalyst

49/Alumina 49/Silica 49/Titania MCM-49

Days on Stream 6.8 4.9 5.8 7.8

Benzene WHSV 17.4 33.1 33.3 33.3

Butene WHSV 4.2 7.9 8.0 8.0

Butene Conversion, % 96.5 94.8 92.5 92.6

Product Selectivity, wt % i-Butane 0.001 0.000 0.001 0.001

1 -Butene & Isobutene 0.000 0.042 0.1 18 0.070

C₅-C₇ 0.079 0.128 0.060 0.093

C₈= 0.501 2.615 1.868 1.272

Cg- π 0.025 0.210 0.121 0.097 + C₁₀-CH Arom. 0.113 0.225 0.131 0.169

Cl3"15 0.130 0.151 0.102 0.219

Cuniene 0.035 0.001 0.000 0.001 t-BB 0.084 0.056 0.045 0.083 i-BB * 0.000 0.000 0.000 0.000 s-BB 94.493 86.719 88.11 1 86.443 n-BB 0.008 0.035 0.015 0.004

DiBB 4.271 9.331 9.052 10.755

TriBB 0.251 0.487 0.376 0.783

Heavies 0.009 0.002 0.000 0.010

Sum 100.0 100.0 100.0 100.0 s-Butvlbenzene (BB) Purity, t-BB/all BB, % 0.088 0.064 0.051 0.096 i-BB*/alI BB, % 0.000 0.000 0.000 0.000 s-BB/all BB, % 99.903 99.895 99.933 99.899 n-BB/all BB, % 0.008 0.041 0.017 0.005

Sum, % 100.0 100.0 100.0 100.0

Di-BB/s-BB Wt Ratio, % 4.5 10.8 10.3 12.4

1 st-order rate constant, hr^"1 48.9 45.6 50.7 36.8

Mesoporosity, cc/g (cumulative

0.12 0.03 0.04 0.03 pore volume in 2-8 nm range)

All samples were collected at 16O⁰C, 300 psig, and 3: 1 benzene/butene molar ratio. Iso-Butylbenzene less than 0.5% in total butylbenzene was not detectable with our GC. [0080] Referring to Table 5, since the first three catalysts (Examples 11-13) contained identical MCM-49 content of 80%, the differences in their s-BB selectivity were most likely from the binder and binder properties. The alumina- bound catalyst had high mesoporosity (0.12 cc/g) and provided high s-BB selectivity of 94.5% and low DiBB selectivity of 4.3%. Catalysts with silica and titania binder had low mesoporosity (0.03 and 0.04 cc/g respectively), and provided much lower s-BB selectivity (86.7% and 88.1% respectively) and much higher DiBB make (9.3% and 9.1% respectively). The catalyst with no binder (100% MCM-49) also had low mesoporosity (0.03 cc/g) and provided low s-BB selectivity (86.4%) and high DiBB make (10.8%). The alumina-bound MCM-49 also produced lowest level of C8-olefins (Cg=) when compared to silica-bound, titania-nound, and binder-free MCM-49.

[0081] The data show clearly that MCM-49 alone does not provide high s-BB selectivity. A suitable amorphous binder with sufficient mesoporosity is desirable for MCM-49 to achieve high s-BB selectivity. Alumina has the required mesoporosity and is preferred binder material for MCM-22 type catalysts. Mesoporosity is believed to provides adequate diffusion path for s-BB once it is formed, thus reducing DiBB formation. Lack of mesoporosity, found in cases of silica-bound MCM-49, titania-bound MCM-49, or binder-free MCM-49, made catalysts less selective for s-BB production.

[0082] The effect of binder and binder pore volume on catalyst selectivity is further depicted in Figure 3.

[0083] 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.

Claims

PCT. CLAIMSWhat we claim is:

1. A process for producing sec-butylbenzene, the process comprising reacting benzene with at least one C₄ alkylating agent under alkylation conditions and in the presence of a particulate alkylation catalyst comprising zeolite beta and/or at least one molecular sieve of the MCM-22 family to produce an alkylation product comprising sec-butylbenzene, wherein the alkylation conditions are such that the benzene is at least partially in the liquid phase and wherein the particles of said alkylation catalyst have a surface to volume ratio of at least 80 inch^"1.

2. The process of claim 1, wherein the particles of said alkylation catalyst have a surface to volume ratio of less than 200 inch^"1.

3. The process of claim 1 or claim 2, wherein the particles of said alkylation catalyst have a surface to volume ratio of about 100 inch^"1 to about 150 inch^"1.

4. The process of any preceding claim, wherein said catalyst comprises 50 to 90 wt%, preferably 60 to 80 wt%, of zeolite beta or said at least one molecular sieve of the MCM-22 family.

5. The process of any preceding claim, wherein said catalyst has a cumulative pore volume in the 2 to 8 nanometer range, as measured by nitrogen porosimetry, of greater than 0.04 cc/gm, preferably greater than 0.07 cc/gm, and more preferably greater than 0.10 cc/gm.

6. The process of any preceding claim, wherein said alkylation catalyst comprises at least one molecular sieve of the MCM-22 family.

7. The process of claim 6, wherein the molecular sieve of the MCM-22 family has an X-ray diffraction pattern including d-spacing maxima at 12.4±0.25, 6.9±0.15, 3.57±0.07 and 3.42±0.07 Angstrom.

8. The process of claim 6 or claim 7, wherein the molecular sieve is selected from MCM-22, PSH-3, SSZ-25, ERB-I, ITQ-I, ITQ-2, MCM-36, MCM-49, MCM-56, UZM-8, and mixtures thereof.

9. The process of any one of claims 6 to 8, wherein, prior to said reacting, said catalyst is contacted with water under conditions to improve the sec- butylbenzene selectivity of the catalyst.

10. The process of any one of claims 6 to 9, wherein said contacting with water is conducted under conditions including a temperature of at least 0⁰C for a time of at least 0.5 hour, preferably a temperature of 10⁰C to 50⁰C for a time of 2 hours to hours.

11. The process of any one of claims 6 to 10, wherein said contacting with water is conducted under conditions sufficient to produce changes in the amplitude or width of at least one peak in the ²⁹Si MAS NMR spectrum of the catalyst in the chemical shift range of -80 to -120 ppm from tetramethylsilane (TMS).

12. The process of any one of claims 6 to 11, wherein said catalyst is dried after being contacted with water and prior to said reacting.

13. The process of claim 12, wherein said catalyst is dried at temperature of 100°C to 200⁰C for a time of 1 hour to 5 hours.

14. The process of any preceding claim, wherein said C₄ alkylating agent comprises a linear butene.

15. The process of claim 14, wherein said linear butene comprises butene-1, butene-2 or a mixture thereof.

16. The process of any preceding claim, wherein said alkylation conditions include an overall molar ratio of benzene to C₄ alkylating agent from 1 : 1 to 20: 1 preferably from 2:1 to 10:1.

17. The process of claim 16, wherein said alkylation conditions also include a temperature of from 60⁰C to 260⁰C, a pressure of 7000 kPa or less, and a feed weight hourly space velocity (WHSV) based on C₄ alkylating agent of from 0.1 to 50 hr ¹.

18. The process of any preceding claim and further comprising oxidizing the sec-butylbenzene to produce a hydroperoxide and cleaving the hydroperoxide to produce phenol and methyl ethyl ketone.

19. The process of claim 19, wherein oxidizing the sec-butylbenzene is conducted in the presence of a catalyst.

20. The process of claim 19 or claim 20, wherein oxidizing the sec- butylbenzene is conducted in the presence of a heterogeneous catalyst.

21. The process of claim 21 wherein the heterogeneous catalyst comprises a metal oxide catalyst.

22. The process of claim 19 or claim 20, wherein oxidizing the sec- butylbenzene is conducted in the presence of a homogeneous catalyst.

23. The process of claim 22 wherein the homogeneous catalyst comprises an N-hydroxy substituted cyclic imide.

24. The process of claim 22 or claim 23 wherein the homogeneous catalyst comprises N-hydroxyphthalimide.

25. The process of any one of claims 19 to 24, wherein the oxidizing is conducted at a temperature of 70⁰C to 200⁰C and a pressure of 0.5 to 20 atmospheres (50 to 2000 kPa).

26. The process of any one of claims 19 to 25, wherein the cleaving of the hydroperoxide is conducted in the presence of a catalyst.

27. The process of any one of claims 19 to 26, wherein the cleaving of the hydroperoxide is conducted in the presence of a homogeneous catalyst.

28. The process of claim 27, wherein said homogeneous catalyst comprises at least one of sulfuric acid, perchloric acid, phosphoric acid, hydrochloric acid, p- toluenesulfonic acid, ferric chloride, boron trifluoride, sulfur dioxide and sulfur trioxide.

29. The process of any one of claims 19 to 26, wherein the cleaving of the hydroperoxide is conducted in the presence of a heterogeneous catalyst.

30. The process of claim 29, wherein said heterogeneous catalyst comprises a smectite clay.

31. The process of any one of claims 19 to 30, wherein the cleaving of the hydroperoxide is conducted at a temperature of 40⁰C to 120⁰C, a pressure of 100 to 1000 kPa, and a liquid hourly space velocity (LHSV) based on the hydroperoxide of 1 to 50 hr^"1.