WO2007093357A1 - Process for producing sec-butylbenzene - Google Patents

Abstract

A process for producing sec-butylbenzene comprises reacting benzene with at least one linear butene under alkylation conditions and in the presence of a catalyst comprising at least one molecular sieve 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 to produce an alkylation product comprising sec- butylbenzene. The alkylation conditions are controlled so that said alkylation product contains less than 1 wt % of butene oligomers.

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, e-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 butyl ene 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 113-421 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. The chemistry is very similar to ethylbenzene and cumene production. However, as the carbon number of the alkylating agent increases, the number of product isomers also increases. For example, ethylbenzene has one isomer, propylbenzene has two isomers (cumene and n- propylbenzene), and butylbenzene has four isomers (n-, iso-, sec-, and t- butylbenzene). For sec-butylbenzene production, it is important to minimize n-, iso-, t-butylbenzene, and phenylbutenes by-product formation. These byproducts, especially iso-butylbenzene, have boiling points very close to sec- butylbenzene and hence are difficult to separate from sec-butylbenzene by distillation (see table below).

Butylbenzene Boiling Point, °C t-Butylbenzene 169 i-Butylbenzene 171 s-Butylbenzene 173 n-Butylbenzene 183

[0007] Moreover, isobutylbenzene and tert-butylbenzene are known to be inhibitors to the oxidation of sec-butylbenzene to the corresponding hydroperoxide, a necessary next step for the production of methyl ethyl ketone and phenol. [0008] It has, however, now been found that the oxidation of sec-butylbenzene is also very sensitive to the presence of the higher (C₈+) olefins that tend to be produced as a result of the oligomerization reactions that compete with alkylation when butene is contacted with benzene in the presence of an acid catalyst. Moreover, certain of these butene oligomers, and in particular certain of the Ci ₂ oligomers, have boiling points very close to sec-butylbenzene making them difficult to separate from alkylation effluent by distillation.

[0009] Thus, according to the invention, it has been found that sec- butylbenzene oxidation is facilitated if the conditions in the alkylation step are controlled so that said alkylation effluent contains less than 1 wt % of butene oligomers. In particular, it has been found that minimizing butene oligomerization depends not only on suitable selection of the alkylation catalyst, but on reducing the local butene to benzene molar ratio, preferably by staged injection of the butene to the alkylation reaction. [0010] US Patent No. 4,459,426 discloses a process for the production of alkylated aromatic hydrocarbons which comprises contacting at least a mole- excess of an aromatic hydrocarbon and a C₂ to C₄ olefin under reaction conditions including the presence of a liquid phase in an alkylation reaction zone with an alkylation catalyst comprising a composite of a steam-stabilized hydrogen Y aluminosilicate zeolite and a mineral oxide binder, said steam-stabilized hydrogen Y aluminosilicate zeolite containing less than 0.7 weight percent of Na₂O and having a unit cell size from 24.00A to about 24.64A. Example I discloses alkylation of benzene with ethylene to produce ethylbenzene using two pressure reactors connected in series, with benzene and ethylene being introduced into the first reactor at a benzene/ethylene mole ratio of 8.2: 1 and additional ethylene being added to the second reactor such that the benzene/ethylene mole ratio .is 10.3:1. Example 6 discloses that secondary butyl benzene can be produced from benzene and either n-butenes or a mixture of butene- 1, trans-butene-2 and cis- butene-2 using the procedure of Example I. [0011] US Patent No. 4,891,458 discloses a process for the alkylation of an aromatic hydrocarbon which comprises contacting a stoichiometric excess of the aromatic hydrocarbon with a C₂ to C₄ olefin under at least partial liquid phase conditions and in the presence of a catalyst comprising zeolite beta. The alkylation process is carried out with addition of olefin in at least two stages, preferably using two or more catalyst beds or reactors in series, with at least a portion of the olefin being added between the catalyst beds or reactors and with interstage cooling being accomplished by the use of a cooling coil or heat exchanger. [0012] It is known from, for example, U.S. Patent No. 4,992,606 that MCM- 22 is an effective catalyst for alkylation of aromatic compounds, such as benzene, with alkylating agents, such as olefins, having from 1 to 5 carbon atoms over a wide range of temperatures from about 0°C to about 500°C, preferably from about - A -

50°C and about 250°C. Similar disclosures are contained in U.S. Patent Nos. 5,371,310 and 5,557,024 but where the zeolites are MCM-49 and MCM-56 respectively.

[0013] In our International Application No. PCT/EP2005/008557, filed August 5, 2005, we have described an integrated process for producing phenol and methyl ethyl ketone, the process comprising (a) contacting a feed comprising benzene and a C₄ alkylating agent under alkylation conditions with a catalyst comprising zeolite beta or an MCM-22 family zeolite to produce an alkylation effluent comprising sec-butylbenzene; (b) oxidizing the sec-butylbenzene to produce a hydroperoxide; and then (c) cleaving the hydroperoxide to produce phenol and methyl ethyl ketone,

SUMMARY

[0014] In one aspect, the present invention resides in a process for producing sec-butylbenzene, the process comprising reacting benzene with at least one linear butene under alkylation conditions and in the presence of a catalyst to produce an alkylation product comprising sec-butylbenzene, wherein said alkylation conditions are controlled so that said alkylation product contains less than 1 wt % of butene oligomers. [0015] Preferably, the catalyst comprises at least one molecular sieve of the

MCM-22 family. Typically, 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.

[0016] 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 3 to aboutlO, more preferably about 4 to about 9.

[0017] Conveniently, said alkylation conditions also 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. [0018] In one embodiment, said reacting is conducted under at least partial liquid phase conditions.

[0019] In a further aspect, the present invention resides in a process for producing sec-butylbenzene, the process comprising reacting benzene under alkylation conditions with a C₄ alkylating agent in the presence of a catalyst comprising at least one molecular sieve of the MCM-22 family, wherein said reacting comprises the steps of

(a) contacting benzene with a first portion of a C₄ alkylating agent in a first reaction stage to produce an alkylation effluent comprising sec-butylbenzene and unreacted benzene; and

(b) contacting said unreacted benzene with at least one further portion of a C₄ alkylating agent in at least one further reaction stage.

[0020] Conveniently, said reaction stages are conducted in a plurality of reaction zones connected in series and each containing said catalyst, with benzene being introduced into the first reaction zone and said alkylating agent being divided between said reaction zones.

[0021] Conveniently, 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. Examples of molecular sieves of the MCM-22 family include MCM-22, PSH-3, SSZ-25, ERB-I, ITQ-I, ITQ-2, MCM-36, MCM-49, MCM-56, UZM-8, and mixtures thereof. Preferably, the molecular sieve of the MCM-22 family is selected from MCM-22, MCM-49, MCM-56 and isotypes thereof. [0022] Conveniently, the C₄ alkylating agent 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, such as a Raffmate-2 stream. [0023] In yet a further aspect, the present invention resides in sec- butylbenzene formed as the direct product of an aromatics alkylation process and containing between about 0.01 wt% and about 1 wt% of butene oligomers. [0024] In still yet 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 and in the presence of a catalyst to produce an alkylation product comprising at least 93 wt% sec-butylbenzene and less than 1 wt% of butene oligomers; (b) oxidizing the sec-butylbenzene from (a) to produce sec- butylbenzene hydroperoxide; and

(c) cleaving the hydroperoxide from (b) to produce phenol and methyl ethyl ketone. [0025] 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 acide either alone or in the presence of a free radical initiator. In one embodiment, the oxidization catalyst is a heterogeneous catalyst. [0026] Conveniently, the oxidizing (b) is conducted at a temperature of about 70⁰C to about 200°C and a pressure of about 0.5 to about 20 atmospheres (50 to 2000 kPa).

[0027] 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. [0028] 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 hr^'1. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 compares the sec-butylbenzene conversion of the processes of Examples 9 to 11 with that of a comparative process using substantially pure sec- butylbenzene. [0030] Figure 2 compares the sec-butylbenzene hydroperoxide selectivity of the processes of Examples 9 to 11 with that of a comparative process using substantially pure sec-butylbenzene.

DETAILED DESCRIPTION OF THE EMBODIMENTS [0031] The present invention is directed to a process for producing sec- butylbenzene by alkylating benzene with a C₄ alkylating agent, and then converting the sec-butylbenzene to phenol and methyl ethyl ketone. The conversion involves initially oxidizing the sec-butylbenzene to produce the corresponding hydroperoxide and then cleaving the resulting hydroperoxide to produce the desired phenol and methyl ethyl ketone.

[0032] In particular, the invention is based on the discovery that the oxidation step to convert the sec-butylbenzene to the corresponding hydroperoxide is highly sensitive to presence of butene oligomers in the alkylation effluent. Moreover, certain butene oligomers, particularly certain Ci₂ oligomers, have boiling points very close to that of sec-butylbenzene and hence can not be readily separated from alkylation effluent by distillation. Thus the present invention seeks to provide an alkylation process and product in which the amount of butene oligomers in the alkylation product is reduced to less than 1 wt %, preferably less than 0.7 wt%, and most preferably less than 0.5 wt%. [0033] It is to be appreciated that the process of the invention, as with any alkylation process, produces an effluent that contains unreacted benzene (typically about 60%) as well as the alkylated species, including sec-butylbenzene and polybutylbenzenes. As used herein, the term "alkylation product" refers to the portion of the effluent that contains the alkylated species but excludes the unreacted benzene. Hence a benzene distillation column, or other separation unit, is needed to convert alkylation effluent to "alkylation product", and an s-BB distillation column, or other separation unit, is need to convert the "alkylation product" to sec-butylbenzene. Benzene Alkylation

[0034] 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%.

[0035] 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 olefϊnic 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.

[0036] 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 A below. Table A

[0037] 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 - 5-2O wt%

Butene-2 - 10-50 wt%

Isobutene - 5-25 wt%

Iso-butane - 10-45 wt%

N-butane - 5-25 wt%

[0038] 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%

[0039] 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 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 process of the invention contains less than 1 wt% iso-butene and less than 0.1 wt% butadiene. [0040] 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.

[0041] 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 alkylation step of the invention 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 of bisphenol-A production.

[0042] 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.

[0043] 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.

[0044] Molecular sieves of the MCM-22 family include those molecular sieves having an X-ray diffraction pattern including d-spacing maxima at 12.4dbO.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. [0045] 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. [0046] 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.

[0047] In one embodiment, the catalyst is unbound and has a crush strength much superior to that of catalysts formulated with binders. Such a catalyst is conveniently prepared by a vapor phase crystallization process, in particular a vapor phase crystallization process that prevents caustic used in the synthesis mixture from remaining in the zeolite crystals as vapor phase crystallization occurs. [0048] 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 aboutlO, more preferably about 4 to about 9.

[0049] In addition, the alkylation conditions conveniently 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. [0050] 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. Preferably, the reactants are at least partially in the liquid phase

[0051] 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 less than 0.5 wt% of isobutylbenzene and tert- butylbenzene and less than 1 wt % of butene oligomers. [0052] 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. [0053] 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 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. Sec-Butyl Benzene Oxidation [0054] 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-butylbezene 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. [0055] 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. [0056] 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), N₅N'- 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.

[0057] 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. [0058] Suitable conditions for the sec-butylbenzene oxidation step include a temperature between about 70°C and about 200°C, such as about 90°C 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. 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 sec-butylbenzene hydroperoxide produced may be concentrated by distilling off the unreacted sec-butylbenzene prior to the cleavage step. Hydroperoxide Cleavage

[0059] 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 20°C to about 150°C, such as about 40°C to about 120⁰C, 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.

[0060] The catalyst employed in the cleavage step can be a homogeneous catalyst or a heterogeneous catalyst. [0061] 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 [0062] 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. [0063] The following Examples are given for illustrative purposes and do not limit the scope of the invention.

Example 1 (Comparative)

Sec-butylbenzene synthesis with MCM-22 and single-step addition of 1- butene

[0064] A sample of fresh MCM-22 catalyst with a nominal composition of 80% zeolite and 20% Versal 300 alumina, extruded to 1/16 inch (1.6 mm) diameter cylinder form, was dried at 26O⁰C for a minimum of 2 hours before testing. 0.5 grams of catalyst (containing 0.4 grams of zeolite) was loaded between two 0.25-inch layers of inert, 8-grit quartz particles that had previously been dried at 121 °C until loaded into the stationary sample basket. 150 grams of reagent grade benzene was added to a 600-ml batch autoclave reactor. The sample basket assembly was installed in the autoclave reactor and sealed. The batch reactor was evacuated and purged twice with N₂ to ensure the elimination of air from the head space. The batch reactor was then pressured to about 200 psig (1480 kPa) with N₂ to ensure proper sealing and absence of leaks. Pressure was reduced to about 50 psig (446 kPa) and about 100 psig (791 kPa) of N₂ was used to quantitatively deliver 25 grams of reagent grade 1-butene from a transfer vessel into the batch reactor. The benzene to 1-butene ratio was 6:1 by weight and 4.3:1 by mole.

[0065] Reactor contents were mixed at 1000 rpm with a vertically positioned impeller located in the center of the stationary sample basket. The reactor was heated to 160°C in about 20 minutes using a programmable autoclave controller to maintain constant ramp rate and temperature. After reaching temperature, the reactor pressure was increased between 600 and 700 psig (4746-5537 kPa) by adding more N₂ to the system. Reaction time-zero was recorded from the point at which temperature and pressure targets (160°C, 600-700 psig) are attained and stable. The reaction period for this evaluation was 5 hours. Samples (1 cc each) were taken at 1-hour increments for GC analysis. At the end of the reaction period, the run was discontinued, the reactor cooled to ambient conditions and the total liquid product recovered for GC analysis.

[0066] Product analysis by GC was based on the assumption that composition of light components in the vapor phase was identical to those dissolved in liquid phase. The analysis was performed using an HP 6890 GC equipped with a DB-I column (6OM, 0.25mm ID, 1 micro liter film thickness) and an FID detector. A 0.2 micro liter portion of the product was injected onto the column and the following temperature program was used to perform the analysis: injection with 2-minute hold at -20°C, ramp at 8°C/min to 275⁰C, hold at 275⁰C for 35 minutes. Response factors were used to convert GC area-based data to actual composition in the product. Butene conversion was determined by measuring unreacted butene relative to feed butene. Data obtained from the evaluation of Example 1 catalyst are reported in Table 1. Table 1. MCM-22 with Single-Step Addition of 1 -Butene in a Batch Reactor

Hours on Stream 1.0 2.0 3.0 4.0 5.0

Feed QzICA= Weight ratio 6.0 6.0 6.0 6.0 6.0

Feed Bz/C4= Molar ratio 4.3 4.3 4.3 4.3 4.3

Butene Conversion, % 72.4 83.7 90.9 94.9 97.1

Product Selectivity. wt% i-Butane 0.058 0.051 0.046 0.041 0.039 n-Butane 0.229 0.193 0.173 0.153 0.143

C₅-C₇ 0.169 0.139 0.132 0.124 0.135

C₈= 1.669 1.498 1.319 1.163 1.128

Cg- 11 0.131 0.096 0.076 0.086 0.079

Ci₂= + C10-C11 Aromatics 0.112 0.105 0.122 0.113 0.131

C13-15 0.063 0.066 0.065 0.093 0.082

Cumene 0.016 0.015 0.015 0.018 0.018 t-Butylbenzene 0.034 0.035 0.038 0.042 0.046 i-Butylbenzene ^* 0.000 0.000 0.000 0.000 0.000 s-Butylbenzene 90.113 90.703 91.050 91.089 91.279 n-Butylbenzene 0.011 0.015 0.013 0.015 0.014

Di-butylbenzene 7.012 6.591 6.459 6.636 6.526

Tri-butylbenzene 0.355 0.299 0.353 0.381 0.349

Heavies 0.028 0.194 0.138 0.045 0.031

Sum 100.0 100.0 100.0 100.0 100.0 s-Butvlbenzene (BB) Puritv, % t-BB/all BB, % 0.038 0.038 0.042 0.046 0.050 i-BB^*/all BB, % 0.000 0.000 0.000 0.000 0.000 s-BB/all BB, % 99.950 99.945 99.944 99.937 99.935 n-BB/all BB, % 0.012 0.016 0.015 0.017 0.015

Sum, % 100.0 100.0 100.0 100.0 100.0

Di-BB/s-BB Wt Ratio, % 7.8 7.3 7.1 7.3 7.1

All samples collected at 160⁰C, 600-700 psig with 150 g of benzene and 25 g of 1-butene. * i-Butylbenzene less than 0.5% in total butylbenzene not detectable with GC used.

Example 2 (Comparative) Sec-Butylbenzene synthesis using MCM-49 with single-step addition of 1- Butene

[0067] The process of Example 1 was repeated but using a fresh MCM-49 catalyst with a nominal composition of 80% zeolite and 20% Versal 300 alumina, extruded to 1/16 inch cylinder form. Data are reported in Table 2. Table 2. MCM-49 with Single-Step Addition of 1-Butene in a Batch Reactor

Hours on Stream 1 0 2 0 3 0 4 0 5 0

Feed Bz/C4= Weight ratio 6 0 6 0 6 0 6 0 6 0

Feed Bz/C4= Molar ratio 4 3 4 3 4 3 4 3 4 3

Butene Conversion, % 70 8 82 2 89 0 93 2 95 3

Product Selectivity. wt% ι-Butane 0 058 0 045 0 041 0 039 0 041 n-Butane 0 203 0 154 0 139 0 133 0 138

C₅-C₇ 0 187 0 146 0 130 0 115 0 128

C₈= 1 484 1 302 1 201 1 078 1 068

C9-11 0 117 0 112 0 094 0 089 0 086

Ci2= + C10-C1₁ Aromatics 0 115 0 112 0 100 0 103 0 114

C13-15 0 082 0 070 0 065 0 077 0 090

Cumene 0 011 0 012 0 014 0 015 0 017 t-Butylbenzene 0 036 0 036 0 038 0 041 0 043 i-Butylbenzene ^* 0 000 0 000 0 000 0 000 0 000 s-Butylbenzene 90 296 90 872 91 464 91 368 91 391 n-Butylbenzene 0 012 0 015 0 014 0 013 0 013

Di-butylbenzene 6 999 6 723 6 360 6 564 6 486

Tπ-butylbenzene 0 368 0 354 0 314 0 340 0 356

Heavies 0 032 0 047 0 026 0 026 0 028

Sum 100 0 100 0 100 0 100 0 100 0 s-Butvlbenzene (BB) Puπtv. % t-BB/all BB, % 0 040 0 040 0 041 0 045 0 047 i-BBVall BB, % 0 000 0 000 0 000 0 000 0 000 s-BB/all BB, % 99 947 99 944 99 943 99 941 99 938 n-BB/all BB, % 0 013 0 016 0 015 0 014 0 015

Sum, % 100 0 100 0 100 0 100 0 100 0

Di-BB/s-BB Wt Ratio, % 7 8 7 4 7 0 7 2 7 1

All samples collected at 160°C, 600-700 psig with 150 g of benzene and 25 g of 1 -butene

* i-Butylbenzene less than 0 5% in total butylbenzene not detectable with GC used

Example 3

Sec-butylbenzene synthesis with MCM-22 and multi-staged addition of equal amounts of 1-butene

[0068] A further 0 5 gram sample of the dπed MCM-22 catalyst used in Example 1 was loaded between two 0 25-inch layers of inert, 8-grit quartz particles that were previously dπed at 121°C until loaded into the stationary sample basket 150 grams of reagent grade benzene was added to a 600 ml batch autoclave reactor The sample basket assembly was installed on the body of the autoclave reactor and sealed The batch reactor was evacuated and purged twice with N₂ to ensure the elimination of air from the head space The batch reactor was then pressured to about 200 psig (1480 kPa) with N₂ to ensure proper sealing and absence of leaks. Pressure was reduced to about 50 psig (446 kPa) and about 100 psig (791 kPa) of N₂ was used to quantitatively deliver 5 grams of reagent grade 1 -butene from a transfer vessel into the batch reactor. [0069] Reactor contents were mixed at 1000 rpm with a vertically positioned impeller located in the center of the stationary sample basket. The reactor was heated to 160°C in about 20 minutes using a programmable autoclave controller to maintain constant ramp rate and temperature. After reaching temperature, the reactor pressure was increased between 600 and 700 psig ( 4746-5537 kPa)by adding more N₂ to the system. Reaction time zero was recorded from the point at which temperature and pressure targets (160°C, 600-700 psig) are attained and stable. At the end of 1-hour, a 1-cc sample was taken from the reactor. Another 5 grams of reagent grade 1 -butene was quantitatively delivered from a transfer vessel into the batch reactor. This step- wise sampling and 5 gram 1 -butene addition procedure was followed until a total of 5 increments (including the initial 5 gram charge) of 1 -butene were added to the reactor. The final benzene to 1- butene ratio was 6:1 by weight and 4.3:1 by mole. The total reaction period for this evaluation was 5 hours. At the end of the reaction period, the run was discontinued, the reactor cooled to ambient conditions and the total liquid product recovered GC analysis. Incremental samples were also evaluated.

[0070] Product analysis by GC and data analysis were identical to those described in Example 1. Data obtained from the evaluation of Example 3 catalyst are reported in Table 3.

Table 3. MCM-22 with Multi-Staged Addition of 1-Butene in a Batch Reactor

Hours on Stream 1 0 2 0 3 0 4 0 5 0

Benzene Weight, g 150 150 150 150 150

Butene Weight, g 5 10 15 20 25

Feed Bz/C4= Weight Ratio 30 0 15 0 10 0 7 5 6 0

Feed Bz/C4= Molar Ratio 21 5 10 7 7 2 5 4 4 3

Butene Conversion, % 94 7 95 5 95 9 95 8 96 6

Product Selectivity. wt% ι-Butane 0 048 0 040 0 046 0 040 0 036 n-Butane 0 167 0 132 0 158 0 136 0 124

C₅-C₇ 0 442 0 233 0 204 0 141 0 109

C₈= 0 721 0 397 0 322 0 290 0 287

Cg- 11 0 035 0 015 0 025 0 037 0 028

Ci2= + C10-C11 Aromatics 0 069 0 038 0 033 0 035 0 042

C13-15 0 024 0 015 0 022 0 039 0 037

Cumene 0 157 0 064 0 023 0 016 0 012 t-Butylbenzene 0 064 0 063 0 061 0 059 0 057 i-Butylbenzene ^* 0 000 0 000 0 000 0 000 0 000 s-Butylbenzene 95 317 95 699 94 853 94 101 93 268 n-Butylbenzene 0 011 0 012 0 012 0 009 0 010

Di-butylbenzene 2 729 3 162 4 083 4 912 5 771

Tri-butylbenzene 0 183 0 121 0 131 0 172 0 197

Heavies 0 033 0 008 0 026 0 014 0 022

Sum 100 0 100 0 100 0 100 0 100 0 s-Butylbenzene (BB) Puπtv. % t-BB/all BB, % 0 068 0 066 0 064 0 063 0 061 i-BBVall BB, % 0 000 0 000 0 000 0 000 0 000 s-BB/all BB, % 99 921 99 921 99 923 99 928 99 929 n-BB/all BB, % 0 012 0 013 0 013 0 009 0 010

Sum, % 100 0 100 0 100 0 100 0 100 0

Di-BB/s-BB Wt Ratio, % 2 9 3 3 4 3 5 2 6 2

All samples collected at 160⁰C, 600-700 psig * i-Butylbenzene less than 0 5% in total butylbenzene not detectable with GC used

Example 4

Sec-butylbenzene synthesis with MCM-49 and multi-staged addition of equal amounts of 1-butene [0071 J The evaluation protocol of Example 3 was repeated but using the MCM-49 catalyst of Example 2 The results are summarized in Table 4 Table 4. MCM-49 with Multi-Staged Addition of 1-Butene in a Batch Reactor

Hours on Stream 1.0 2.0 3.0 4.0 5.0

Benzene Weight, g 150 150 150 150 150

Butene Weight, g 5 10 15 20 25

Feed Bz/C4= Weight Ratio 30.0 15.0 10.0 7.5 6.0

Feed Bz/C4= Molar Ratio 21.5 10.7 7.2 5.4 4.3

C4= Conv % 92.9 94.4 94.9 95.1 96.8

Product Selectivity, wt% i-Butane 0.041 0.046 0.043 0.045 0.038 n-Butane 0.150 0.166 0.144 0.147 0.131

C₅-C₇ 0.485 0.258 0.164 0.120 0.105

C₈= 0.650 0.446 0.326 0.318 0.273

Cg- 11 0.045 0.046 0.042 0.030 0.034

Ci2= + C10-C11 Aromatics 0.043 0.046 0.042 0.036 0.036

C13-15 0.028 0.028 0.027 0.034 0.037

Cumene 0.024 0.018 0.012 0.008 0.008 t-Butylbenzene 0.068 0.062 0.063 0.061 0.058 i-Butylbenzene ^* 0.000 0.000 0.000 0.000 0.000 s-Butylbenzene 96.331 95.693 95.206 94.362 93.513 n-Butylbenzene 0.011 0.018 0.010 0.011 0.009

Di-butylbenzene 1.991 3.007 3.775 4.663 5.547

Tri-butylbenzene 0.115 0.148 0.124 0.151 0.184

Heavies 0.019 0.018 0.022 0.017 0.026

Sum 100.0 100.0 100.0 100.0 100.0 s-Butvlbenzene (BB) Puritv. % t-BB/all BB, % 0.071 0.065 0.066 0.064 0.062 i-BB7all BB, % 0.000 0.000 0.000 0.000 0.000 s-BB/all BB, % 99.918 99.917 99.923 99.925 99.928 n-BB/all BB, % 0.011 0.019 0.011 0.011 0.010

Sum, % 100.00 100.00 100.00 100.00 100.00

Di-BB/s-BB Wt Ratio, % 2.1 3.1 4.0 4.9 5.9

All samples collected at 160⁰C, 600-700 psig. * i-Butylbenzene less than 0.5% in total butylbenzene not detectable with GC used.

Example 5

Sec-butylbenzene synthesis with jet-milled MCM-49 and multi-staged addition of equal amounts of 1-butene [0072] A sample of fresh MCM-49 was jet milled and then extruded with Versal 200 alumina into a 1/20 inch (1.3 mm) quadailobe catalyst with a nominal composition of 60% zeolite and 40% alumina. 0.667 g of catalyst (containing 0.4 grams of zeolite) was loaded into the batch reactor and the evaluation protocol of Example 3 was repeated. Data are reported in Table 5. Table 5. Jet-Milled MCM-49 with Multi-Staged Addition of 1-Butene in a Batch

Reactor

Hours on Stream 1.0 2.0 3.0 4.0 5.0

Benzene Weight, g 150 150 150 150 150

Butene Weight, g 5 10 15 20 25

Feed Bz/C4= Weight Ratio 30.0 15.0 10.0 7.5 6.0

Feed BzJCA= Molar Ratio 21.5 10.7 7.2 5.4 4.3

Butene Conversion, % 92.4 93.1 93.7 93.2 93.1

Product Selectivity. wt% i-Butane 0.051 0.044 0.038 0.040 0.037 n-Butane 0.197 0.157 0.136 0.145 0.134

C₅-C₇ 0.439 0.254 0.162 0.101 0.081

C₈= 0.751 0.325 0.261 0.251 0.247

C9-11 0.195 0.069 0.054 0.050 0.053 + C10-C11 Aromatics 0.030 0.034 0.031 0.036 0.036

C13-15 0.022 0.028 0.024 0.030 0.035

Cumene 0.027 0.019 0.012 0.010 0.010 t-Butylbenzene 0.064 0.062 0.059 0.057 0.055 i-Butylbenzene ^* 0.000 0.000 0.000 0.000 0.000 s-Butylbenzene 95.479 95.827 95.428 94.937 94.432 n-Butylbenzene 0.016 0.015 0.013 0.012 0.012

Di-butylbenzene 2.294 2.914 3.621 4.159 4.681

Tri-butylbenzene 0.138 0.121 0.138 0.154 0.163

Heavies 0.297 0.130 0.024 0.017 0.024

Sum 100.0 100.0 100.0 100.0 100.0 s-Butvlbenzene (BB) Puritv. % t-BB/all BB, % 0.067 0.064 0.061 0.060 0.058 i-BB7all BB, % 0.000 0.000 0.000 0.000 0.000 s-BB/all BB, % 99.916 99.920 99.925 99.927 99.929 n-BB/all BB, % 0.016 0.015 0.014 0.013 0.013

Sum, % 100.0 100.0 100.0 100.0 100.0

Di-BB/s-BB Wt Ratio, % 2.4 3.0 3.8 4.4 5.0

All samples collected at 160⁰C, 600-700 psig. * i-Butylbenzene less than 0.5% in total butylbenzene not detectable with GC used.

Example 6: Comparison of Batch Reactor Results

[0073] Table 6 compares batch reactor data of Examples 1 to 5 collected at 5 hours reaction time. When operated with a single-step addition of 1 -butene,

MCM-22 and MCM-49 catalysts produced sec-butylbenzene with 91% selectivity.

When operated with multi-staged addition of 1 -butene to reach the same final benzene/1 -butene molar ratio of 4.3:1, MCM-22 and MCM-49 catalysts improved sec-butylbenzene selectivity to 93-94%. Multi-staged addition also provided a 3- fold reduction of butene oligomers, and a reduction of di-butylbenzenes and tri- butylbenzenes. Table 6. Comparison of Batch Reactor Results at the End of Run

Mode of Butene Addition Single-Step Addition Multi-Staged (5x 5 g) Addition

Example Example 1 Example 2 Example 3 Example 4 Example 5

Jet-milled

Catalyst MCM-22 MCM-49 MCM-22 MCM-49 MCM-49

Benzene (Bz) Weight, g 150 150 150 150 150

Total Butene (C₄ ⁼) Weight, g 25 25 5 x 5 5 x 5 5 x 5

Total Feed Bz/C4= Weight Ratio 6.0 6.0 6.0 6.0 6.0

Total Feed Bz/C4= Molar Ratio 4.3 4.3 4.3 4.3 4.3

Butene Conversion, % 97.1 95.3 96.6 96.8 93.1

Product Selectivitv. wt% i-Butane 0.039 0.041 0.036 0.038 0.037 n-Butane 0.143 0.138 0.124 0.131 0.134

C₅-C₇ 0.135 0.128 0.109 0.105 0.081

C₈= 1.128 1.068 0.287 0.273 0.247

Cg- 11 0.079 0.086 0.028 0.034 0.053

Ci2= + C10-C11 Aromatics 0.131 0.114 0.042 0.036 0.036

C13-15 0.082 0.090 0.037 0.037 0.035

Cumene 0.018 0.017 0.012 0.008 0.010 t-Butylbenzene 0.046 0.043 0.057 0.058 0.055 i-Butylbenzene ^* 0.000 0.000 0.000 0.000 0.000 s-Butylbenzene 91.279 91.391 93.268 93.513 94.432 n-Butylbenzene 0.014 0.013 0.010 0.009 0.012

Di-butylbenzene 6.526 6.486 5.771 5.547 4.681

Tri-butylbenzene 0.349 0.356 0.197 0.184 0.163

Heavies 0.031 0.028 0.022 0.026 0.024

Sum 100.0 100.0 100.0 100.0 100.0 s-Butylbenzene (BB) Purity, % t-BB/all BB, % 0.050 0.047 0.061 0.062 0.058 i-BB7all BB, % 0.000 0.000 0.000 0.000 0.000 s-BB/all BB, % 99.935 99.938 99.929 99.928 99.929 n-BB/all BB, % 0.015 0.015 0.010 0.010 0.013

Sum, % 100.00 100.00 100.00 100.00 100.00

Di-BB/s-BB Wt Ratio, % 7.1 7.1 6.2 5.9 5.0 All samples collected at 160⁰C, 600-700 psig, and 5 hours reaction time.

* i-Butylbenzene less than 0.5% in total butylbenzene not detectable with GC used.

[0074] It is to be appreciated that at a 6: 1 benzene/ 1 -butene weight ratio (4.3 molar ratio), the 1-butene concentration is 14.3 wt% (1/7) if all of the feed 1- butene mixes with all of the feed benzene instantaneously upon addition. Given the relatively slow reaction rates and fast stirring, this is a reasonable approximation with a well-stirred autoclave reactor, and can be approached in a fixed bed reactor with adequate feed distribution nozzles at each feed injection level. The local concentrations would be higher with non-ideal mixing. For a fixed bed system, there will normally be two or more catalyst beds, preferably with a separate olefin feed injection zone upstream of at least two of these beds. Within each zone, there may be a single nozzle for introduction of olefins into the bulk flowing mixture, or preferably multiple nozzles. [0075] When the same amount of butene was added stepwise (5-steps as in Examples 3-5) with nearly complete conversion of butene in between additions (92-97% butene conversion as in Examples 3-5), the maximum olefin concentration would be 2.9 wt% (20% x 1/7). In a fixed bed reactor with essentially steady state operation, having multiple feed injection points is more or less the equivalent of multiple feed addition events to a batch reactor.

Example 7

Sec-butylbenzene synthesis with jet-milled MCM-49 in fixed-bed reactor at

3:1 benzene/2-butene molar ratio

[0076] 0.4 g of the jet-milled MCM-49 catalyst of Example 5 (but cut to 1/16 inch [1.6 mm] length) 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 at 150°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 until reactor pressure reached the desired 300 psig (2170 kPa). Benzene flow was then reduced to 7.63 cc/hr. 2-Butene feed (57.1% cis- butene, 37.8% trans-butene, 2.5% n-butane, 0.8% isobutene and 1 -butene, and 1.8% others) was introduced from a syringe pump at 2.57 cc/hr. Feed benzene/butene molar ratio was maintained at 3:1 for the entire run. The reactor temperature was adjusted to 160°C. Liquid products were collected at reactor conditions of 160°C and 300 psig (2170 kPa) in a cold-trap and analyzed off line. Butene conversion was determined by measuring unreacted butene relative to feed butene. Representative data are shown in Table 7. Example 8

Sec-butylbenzene synthesis with jet-milled MCM-49 in fixed-bed reactor at

6:1 benzene/2-butene molar ratio

[0077] The process of Example 7 was repeated but using 0.6 g of the jet- milled MCM-49 catalyst of Example 5 (cut to 1/16 inch [1.6 mm] length) and with the feed benzene/butene molar ratio being maintained at 6:1 for the entire run (benzene at 11.47 cc/hr and butene at 1.93 cc/hour). Representative data are also shown in Table 7.

Table 7 sec-Butylbenzene Production with Jet-Milled MCM-49 in Fixed-bed

Reactor

Example Example 7 Example 8

Feed Bz/C4= Weight Ratio 3 1 6 1

Feed Bz/C4= Molar Ratio 4 2 1 8 4 1

Days on Stream 1 8 2 8 6 8 7 8

Butene WHSV, h ¹ 4 0 4 0 2 0 2 0

Benzene WHSV, h ¹ 16 7 16 7 16 7 16 7

Butene Conversion, % 96 30 95 41 97 41 97 33

Product Selectivity, wt % ι-Butane 0 003 0 003 0 000 0 000 n-Butane 0 000 0 000 0 000 0 000

C₅-C₇ 0 055 0 059 0 099 0 107

C₈= 0 443 0 865 0 466 0 474

C9-11 0 019 0 042 0 016 0 033

Ci₂= + C10-C11 Aromatics 0 157 0 135 0 066 0 073

C13-15 0 158 0 166 0 062 0 071

Cumene 0 243 0 251 0 156 0 159 t-Butylbenzene 0 093 0 078 0 078 0 068 i-Butylbenzene ^* 0 000 0 000 0 000 0 000 s-Butylbenzene 92 547 93 054 96 257 96 244 n-Butylbenzene 0 013 0 009 0 011 0 010

Di-butylbenzene 5 546 5 040 2 667 2 620

Tri-butylbenzene 0 405 0 287 0 113 0 125

Heavies 0 320 0 013 0 010 0 016

Sum 100 000 100 000 100 000 100 000 s-Butvlbenzene (BB) Puπtv, % t-BB/all BB, % 0 100 0 084 0 081 0 071 ι-BB7all BB, % 0 000 0 000 0 000 0 000 s-BB/all BB, % 99 886 99 907 99 909 99 919 n-BB/all BB, % 0 014 0 009 0 011 0 011

Sum, % 100 00 100 00 100 00 100 00

Di-BB/s-BB Wt Ratio, % 6 0 5 4 2 8 2 7

All samples collected at 160°C and 300 psig * iso-Butylbenzene less than 0 5% in total butylbenzene is not detectable with oui GC [0078] When operated at 3:1 benzene/2 -butene molar ratio (or 4.2:1 weight ratio), the 2-butene concentration is 18.9 wt% (1/5.3) if 2-butene mixes with benzene instantaneously. At this benzene/2-butene molar ratio, the MCM-49 catalyst produced sec-butylbenzene with 93% selectivity. [0079] When operated at 6:1 benzene/2-butene molar ratio (or 8.4:1 weight ratio), the 2-butene concentration is 10.6 wt% (1/9.4) if 2-butene mixes with benzene instantaneously. At this benzene/2-butene molar ratio, the MCM-49 catalyst produced sec-butylbenzene with 96% selectivity. By-products such as butene oligomers and di-butylbenzenes and tri-butylbenzenes were reduced by about 50%. Thus reducing local concentration of butene in the fixed-bed reactor has a positive impact on sec-butylbenzene selectivity.

Example 9:

Oxidation of sec-butylbenzene produced in batch reactor by multi-staged butene addition at total benzene/butene molar ratio of 4.3:1 [0080] The liquid products produced in Examples 3, 4, and 5 (batch reactor by multi-staged 1 -butene addition) were combined. Benzene was removed under reduced pressure by a Roto-evaporator. Sec-butylbenzene was isolated by distillation under 50 mmHg vacuum using a 26-plate vacuum-jacked Older Shaw column with a reflux ratio of 10:1. Oxidation of sec-butylbenzene was carried out in a 100 cc Parr autoclave at 115°C and 250-260 psig (1825-1894 kPa) nitrogen/oxygen (80/20) pressure. Into the 100 cc Parr autoclave was charged 0.185g (1.1134 mmole) N-hydroxyphthalimide (NHPI) from Aldrich and 43.2 g (321.5 mmole) of the distilled sec-butylbenzene. The contents of the autoclave were pressurized to 220 psig (1618 kPa) with nitrogen followed by oxygen to an 80/20 molar ratio at room temperature. Next the mixture was heated to 115°C with a mechanical stirring rate of 720 rpm. The temperature was maintained at 115°C for 6 hours with frequent gas sampling of the head-space for nitrogen and oxygen. The oxygen content of approximately 20% was maintained throughout the heating period by replenishment from an oxygen PVT (pressure, volume, temperature) vessel. At the completion of the run the liquid phase was analyzed by GC. Sec-butylbenzene conversion was 22.2 wt% and selectivity to sec- butylbenzene hydroperoxide was 92.3 wt%. Example 10:

Oxidation of sec-butylbenzene produced in Ωxed bed reactor at 3:1 benzene/butene molar ratio

[0081] Liquid products produced in Example 7 (fixed-bed reactor at 3:1 benzene/butene molar ratio) were combined. The same procedure described in Example 9 was followed for sec-butylbenzene isolation and oxidation. Sec- butylbenzene conversion was 14.0 wt% and selectivity to sec-butylbenzene hydroperoxide was 91.0 wt%.

Example 11: Oxidation of sec-butylbenzene produced in fixed bed reactor at 6:1 benzene/butene molar ratio

[0082] Liquid products produced in Example 8 (fixed-bed reactor at 6:1 benzene/butene molar ratio) were combined. The same procedure described in Example 9 was followed for sec-butylbenzene isolation and oxidation. Sec- butylbenzene conversion was 21.9 wt% and selectivity to sec-butylbenzene hydroperoxide was 92.8 wt%.

Example 12:

Comparison of sec-Butylbenzene Oxidation

[0083] Figures 1 and 2 compare the sec-butylbenzene conversion and sec- butylbenzene hydroperoxide selectivity respectively of the processes of Examples 9 to 11 with that of comparative process using TCI sec-butylbenzene (containing 19 ppm olefinic impurities) as a bench-mark material.

[0084] Figure 1 shows the improvement in sec-butylbenzene conversion with multi-staged addition of butene (Example 9 with 22.2% conversion) or with 6:1 benzene/butene molar ratio (Example 11 with 21.9% conversion), as compared with the 14% conversion obtained with the 3:1 benzene/butene molar ratio of Example 10. The highest conversion was, however, obtained with the TCI sec- butylbenzene (24.8% conversion).

[0085] Figure 2 shows the improvement in sec-butylbenzene hydroperoxide selectivity with multi-staged addition of butene (Example 9 with 92.3% selectivity) or with 6:1 benzene/butene molar ratio (Example 11 with 92.8% selectivity). These selectivities were higher than those obtained with the both 3: 1 benzene/butene molar ratio of Example 10 (91% selectivity) and the TCI feed (91.4 % selectivity). [0086] 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

1. A process for producing sec-butylbenzene, the process comprising reacting benzene with at least one linear butene under alkylation conditions and in the presence of a catalyst to produce an alkylation effluent comprising sec- butylbenzene, wherein said alkylation conditions are controlled so that said alkylation product contains 1 wt % or less of butene oligomers.

2. The process of claim 1, wherein the catalyst comprises at least one molecular sieve of the MCM-22 family.

3. The process of claim 1 or claim 2, 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.

4. The process of any preceding claim, wherein said alkylation conditions include an overall molar ratio of benzene to linear butene from 1 :1 to 20:1, preferably from 4: 1 to 9: 1.

5. The process of any preceding claim, wherein said reacting is conducted in a catalytic distillation reactor.

6. The process of any preceding claim, wherein said linear butene is added to the process in stages.

7. A process for producing sec-butylbenzene, the process comprising reacting benzene under alkylation conditions with a C₄ alkylating agent in the presence of a catalyst comprising at least one molecular sieve of the MCM-22 family, wherein said reacting comprises the steps of: (a) contacting benzene with a first portion of a C₄ alkylating agent in a first reaction stage to produce an alkylation effluent comprising sec-butylbenzene and unreacted benzene; and (b) contacting said unreacted benzene with at least one further portion of a C₄ alkylating agent in at least one further reaction stage.

8. The process of claim 7, wherein said reaction stages are conducted in a plurality of reaction zones connected in series and each containing said catalyst, with benzene being introduced into the first reaction zone and said alkylating agent being divided between said reaction zones.

9. The process of claim 7 or claim 8, wherein said molecular sieve of the MCM-22 family is a molecular sieve 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.

10. The process of any of claims 7 to 9, wherein said C₄ alkylating agent in (a) comprises a linear butene.

11. The process of any one of claims 1 to 6 or claim 10, wherein said linear butene is contained in a mixed C₄ stream.

12. The process of any preceding claim, wherein said alkylation conditions include a temperature of from 60°C to 260°C and/or a pressure of 7000 kPa or less and/or a feed weight hourly space velocity (WHSV) based on alkylating agent of from 0.1 to 50 hr^"'.

13. The process of any preceding claim, wherein said reacting is conducted under at least partial liquid phase conditions.

14. Sec-butylbenzene produced by the process of any preceding claim.

15. Sec-butylbenzene formed as the direct product of an aromatics alkylation process and containing from 0.01 wt% to 1 wt%, preferably from 0.05 wt% to 0.8 wt% of butene oligomers.

16. The use of the sec-butylbenzene of claim 14 or claim 15 in a process for the conversion of alkylaromatics to phenol and methyl ethyl ketone.

17. A process for producing phenol and methyl ethyl ketone, the process comprising:

(a) reacting benzene with at least one linear butene under alkylation conditions and in the presence of a catalyst to produce an alkylation effluent comprising at least 93 wt% sec-butylbenzene and from 0.01 wt% to 1 wt % of butene oligomers; (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.

18. The process of claim 17, wherein said catalyst comprises at least one molecular sieve of the MCM-22 family.

19. The process of claim 17 or claim 18, wherein said molecular sieve of the MCM-22 family is a molecular sieve 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.

20. The process of any one of claims 17 to 19, wherein said oxidizing is conducted in the presence of a catalyst selected from:

(a) an oxo (hydroxo) bridged tetranuclear metal complex comprising manganese;

(b) 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; (c) an N-hydroxy substituted cyclic imide either alone or in the presence of a free radical initiator; and (d) N,N',N"-trihydroxyisocyanuric acid either alone or in the presence of a free radical initiator.

21. The process of any one of claims 17 to 20, wherein the oxidizing is conducted at a temperature of 70°C to 200°C and/or a pressure of 50 to 2000 kPa (0.5 to 20 atmospheres).