PRODUCTION OF ALKYLAROMATIC COMPOUNDS

FIELD

[0001] This invention relates to a process for producing alkylaromatic compounds and to the use of the resultant alkylaromatic compounds in the production of phenol.

BACKGROUND

[0002] Alkylaromatic compounds are important products in the chemical industry and are conveniently produced by alkylation of aromatic compounds with one or more olefins in the presence of an acid catalyst. For example, ethylbenzene is produced commercially by the alkylation of benzene with ethylene, cumene is produced by the alkylation of benzene with propylene, sec-butylbenzene is produced by the alkylation of benzene with n-butene, and cyclohexylbenzene is produced by the alkylation of benzene with cyclohexene.

[0003] In general, existing commercial processes for the alkylation of aromatic compounds with olefins are highly selective and produce the desired monoalkylated product in high yield. However, a competing reaction is oligomerization of the olefin feed to produce oligomers that, in some cases, may boil at similar temperatures to the target alkylaromatic product making the removal of these oligomers by conventional distillation very difficult. [0004] It has now been found that the presence of these oligomers in the alkylaromatic product can be highly deleterious to subsequent use of the product. For example, an important use of cumene and sec-butylbenzene is in the production of phenol by the Hock process, in which cumene or sec-butylbenzene is oxidized to the corresponding hydroperoxide and then the hydroperoxide is cleaved to produce equimolar amounts of phenol and acetone or methyl ethyl ketone. As a result of spiking tests, it has been found that the presence of olefin oligomers, and in particular Ci ₂ oligomers, in the sec-butylbenzene produced by the alkylation of benzene with n-butene significantly inhibits the oxidation reaction to produce the hydroperoxide. In particular, it is believed that the oxidation proceeds through the formation of peroxy and/or alkyl radical

intermediates and that the oligomers react preferentially with these intermediates to form more stable radicals and hence terminate the reaction. Similar results are obtained in the oxidation of cumene produced by the alkylation of benzene with propylene.

[0005] According to the invention, it has now been found that the oligomer impurities in the product of the alkylation of aromatic compounds with olefins can be selectively removed by hydrogenation of the product in the presence of a rhodium-containing catalyst. Surprisingly, the hydrogenation can be conducted without significant saturation of the aromatic species and, at least in the case of cumene and sec-butylbenzene, it has been found that the selective hydrogenation significantly increases the oxidation activity of the alkylated product.

(0006] British Patent No. 844,242 discloses a catalyst prepared by depositing platinum, indium, palladium, rhodium, tantalum, tungsten, chromium oxide or molybdenum oxide on a high surface area amphoteric oxide which has had iron, cobalt or nickel deposited thereon and then been roasted at above 65O ⁰ C. The catalyst is reported to be useful in the dealkylation of alkyl aromatics, such as toluene, xylenes, cumene, mesitylene, pseudo-cumene and diethyl benzene, at 250 to 500 ⁰ C and up to 200 psig (1.38 MPag); and in the hydrogenation of unsaturated compounds, such as ethylene, propylene, butenes, butadienes, pentenes, hexenes, di-isobutylene, propylene dimer and trimer, benzene, toluene, xylenes, ethyl benzene, cumene, pseudo-cumene, mesitylene, diphenyl, naphthalene, unsaturated fatty acids, alcohols and esters, at 150 to 400 ⁰ C and up to 1000 psig (6.9 MPag). There is, however, no disclosure or suggestion that a rhodium-containing catalyst should be useful in the selective hydrogenation of olefin isomers in the presence of an alkylaromatic compound obtained from the olefin.

[0007] US Patent No. 3,755,194 discloses a hydrogenation catalyst comprising the reduced reaction product complex of equimolar amounts of rhodium trichloride and a π-bonding aromatic ligand selected from the group consisting of tyrosine, N-phenyl-anthranilic acid, fluorescein, and rhodamine B. The catalyst is reported to be useful for carrying out rapid and selective hydrogenation of carbonyl-group-containing olefins, e.g. for hydrogenating

methyl vinyl ketone to methyl ethyl ketone. However, the catalyst is also reported to be useful in the hydrogenation of pyridine and aromatic compounds. Again there is no disclosure or suggestion that a rhodium-containing catalyst should be useful in the selective hydrogenation of olefin isomers in the presence of an alkylaromatic compound obtained from the olefin.

[0008] US Patent No. 3,974,095 discloses a method of preparing a catalyst for hydrogenation, isomerization and hydrosilylation of alkenes having from 2-16 carbon atoms, comprising the steps of reacting a halogen compound of a metal selected from the group consisting of palladium, platinum, rhodium and ruthenium with polyphenylene of a specific weight of 1000-3000 in an organic solvent at a temperature within the range of 60-120°C, so resulting in the formation of a polyphenylene complex, and effecting the reduction of the resultant composition by reaction with a reducing agent to yield a catalyst having from 0.5 - 20 percent, by weight, of said metal.

[0009] US Patent No. 4,517,390 discloses a process for the hydrogenation of an unsaturated organic compound in the presence of a catalyst comprising a water-soluble complex of a platinum group metal containing as a ligand a water- soluble phosphine selected from carboxy-triaryl phosphines and hydroxy-triaryl phosphines in a reaction medium comprising an aqueous phase and an organic phase, wherein the reaction medium also includes an amphiphilic reagent, which contains polar and non-polar moieties and which is substantially soluble in the aqueous phase and substantially insoluble in the organic phase. Suitable unsaturated organic compounds are said to include open-chain (terminal and internal, preferably C ₃ -C ₂ o) and cyclic olefins, styrene derivatives, polymers such as styrene-butadiene block copolymers (which require selective hydrogenation of the olefinic moieties to improve oxidative stability), aromatics and aldehydes, particularly long chain aldehydes.

[0010] US Patent No. 5,476,958 discloses a process for the removal of olefins from silanes or silane mixtures obtained during methylchlorosilane synthesis, comprising reacting the olefins in the silanes or silane mixture with hydrogen in the presence of a hydrogenation catalyst selected from the group consisting of iron, nickel, cobalt, rhodium, ruthenium, platinum and palladium.

[0011] US Patent No. 6,156,694 discloses a Raney cobalt catalyst comprising cobalt, iron and a third metal wherein the third metal is selected from the group consisting of nickel, rhodium, ruthenium, palladium, platinum, osmium, iridium or a combination of any of these metals and wherein the concentration of the cobalt in the catalyst on a dry basis is at least 30% but not more than about 70% by weight; the concentration of the iron in the catalyst on a dry basis is from at least 5 to 40% by weight; the content of the third metal in the catalyst on a dry basis is from about 1 to not more than 6% by weight. The catalyst is reported to be useful in hydrogenating unsaturated organic compounds comprising olefins, acetylenes, ketones, aldehydes, amides, carboxylic acids, esters of carboxylic acids, nitro compounds, nitriles, and imino compounds and particularly hydrogenating nitrites to primary amines.

[0012] US Patent Application Publication No. 2006/0009666 discloses a process for the hydrogenation of a hydrocarbon feed containing unsaturated components, which comprises contacting the feed with hydrogen in the presence of a catalyst including at least one Group VIII metal on a noncrystalline, mesoporous inorganic oxide support having at least 97 volume percent interconnected mesopores based upon mesopores and micropores, having BET surface area of at least 300 m ² /g, and a pore volume of at least 0.3 cm ³ /g. The Group VIII metal can be a noble metal selected from the group consisting of palladium, platinum, rhodium, ruthenium, and iridium. The process is particularly applicable to the removal of aromatics from hydrocarbon distillates but can also be used in the selective hydrogenation of acetylenic and/or dienic impurities in a feed containing at least one monoolefin.

SUMMARY

[0013] In one aspect, the present invention resides in a process for producing an alkylaromatic compound, the process comprising:

(a) contacting an aromatic compound with an olefin under alkylation conditions and in the presence of an alkylation catalyst to produce an alkylation effluent comprising an alkylaromatic compound and at least one oligomer of said olefin; and

(b) treating said effluent with hydrogen under hydrogenation conditions in the presence of a rhodium-containing catalyst to selectively hydrogenate said at least one oligomer.

[0014] Conveniently, the aromatic compound comprises benzene and the olefin comprises at least one C ₂ to C ₆ olefin, such as propylene or a linear butene, for example 1 -butene, 2-butene or a mixture of these olefins.- -- ^{■ ;}

[0015] In one embodiment, the alkylation catalyst comprises zeolite beta or at least one molecular sieve of the MCM-22 family. 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. 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. Preferably, the molecular sieve is selected from MCM-22, MCM-49, MCM-56 and isotypes thereof.

[0016] Conveniently, said alkylation conditions also include, independently: a temperature of from about 6O ⁰ C to about 260°C, a pressure of 7000 kPa or less; a feed weight hourly space velocity (WHSV) based on said olefin of from about 0.1 to 50 hr ^"1 ; a molar ratio of aromatic compound to olefin from about 1 to about 50, preferably from about 2 to about 10. In preferred embodiments the alkylation conditions mentioned above as independent parameters may be used in combinations of any two or more thereof. [0017] In one embodiment, said contacting (a) is conducted under at least partial liquid phase conditions.

[0018] In a further aspect, in which the convenient or preferred aspects of contacting (a) and/or treating (b) are as described above, the present invention resides in a process for producing phenol, the process comprising:

(a) contacting benzene with an olefin under alkylation conditions and in the presence of an alkylation catalyst to produce an alkylation effluent comprising an alkylbenzene compound and at least one oligomer of said olefin;

(b) treating said effluent with hydrogen under hydrogenation conditions in the presence of a rhodium-containing catalyst to selectively hydrogenate said at least one oligomer;

(c) oxidizing the alkylbenzene compound in said treated effluent to produce a hydroperoxide; and

(d) cleaving the hydroperoxide from (c) to produce phenol and a ketone.

[0019] Conveniently, the olefin is ethylene, propylene or a linear butene and preferably is 1 -butene, 2-butene or a mixture of-these olefins.

[0020] Conveniently, the catalyst employed in the treating (b) comprises a rhodium complex, such as a rhodium halide, eg rhodium chloride. In one embodiment, the catalyst employed in the treating (b) also comprises a phase transfer agent, such as a quaternary ammonium compound.

[0021] Conveniently, the treating (b) is conducted at conditions including, independently: a temperature of about O ⁰ C to about 300°C; a pressure of about 15 to about 1000 kPa; a hydrogen to hydrocarbon mole ratio of about 1 : 1000 to about

1000: 1. In preferred embodiments the treating (hydrogenation) conditions mentioned above as independent parameters may be used in combinations of any two or more thereof.

[0022] Conveniently, said treating (b) is conducted under hydrogenation conditions such that at least 70 wt%, preferably at least 80 wt%, of said at least one oligomer is hydrogenated.

[0023] Conveniently, said treating (b) is conducted under hydrogenation conditions such that no more than 5 wt%, preferably no more than 2 wt%, of said alkylbenzene compound is hydrogenated.

[0024] Conveniently, the cleaving (d) 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.

[0025] Conveniently, the cleaving (d) is conducted at a temperature of about 40 ⁰ C to about 120 ⁰ C and/or a pressure of about 100 to about 2500 kPa and/or a liquid hourly space velocity (LHSV) based on the hydroperoxide of about

0.1 to about 100 hr ^"1 .

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a bar chart graph comparing the degree of conversion obtained in the oxidation of a commercially available sec-butylbenzene sample and the sec-butylbenzene product of Example 1 , both with and without prior hydrogenation with a rhodium catalyst.

[0027] Figure 2 is a bar chart graph comparing the degree of conversion obtained in the oxidation of a commercially available sec-butylbenzene sample and the sec-butylbenzene product of Example 1, after hydrogenation with different rhodium and palladium catalysts.

[0028] Figure 3 is a bar chart graph comparing the degree of conversion obtained in the oxidation of the cumene product of Example 2, both with and without prior hydrogenation with a rhodium catalyst.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] The present invention is directed to a process for producing an alkylaromatic compound by (a) initially contacting an aromatic compound with an olefin under alkylation conditions and in the presence of an alkylation catalyst to produce an alkylation effluent comprising the desired alkylaromatic compound and then (b) treating the alkylation effluent with hydrogen under hydrogenation conditions in the presence of a rhodium-containing catalyst. In particular it is found that the alkylation step (a) is accompanied by oligomerization of the olefin to produce olefin oligomers, but these oligomers can be selectively removed by hydrogenation in the presence of the rhodium-containing catalyst in the treatment step (b).

[0030] Although the present process can be employed in the alkylation of any aromatic compound with any olefin, it is particularly applicable to the alkylation of benzene with a C ₃ to C ₆ olefin, such as propylene or a linear butene (for example 1 -butene and/or 2-butene). Thus cumene and sec-butylbenzene are frequently used as intermediates in the production of phenol by the Hock process, in which cumene or sec-butylbenzene is oxidized to the corresponding hydroperoxide and then the hydroperoxide is cleaved to produce equimolar amounts of phenol and acetone or methyl ethyl ketone. However, the oxidation

step of the Hock process is highly sensitive to the presence of impurities, including olefin oligomers, and it is found that hydrogenation in the presence of a rhodium-containing catalyst can be used to selectively remove these oligomers without excessive saturation of the aromatic rings.

Aromatics Alkylation

[0031] The term "aromatic" in reference to the alkylatable compounds which are useful herein is to be understood in accordance with its art-recognized scope to include any alkyl substituted and unsubstituted mono- and polynuclear compound. Compounds of an aromatic character which possess a hetero atom are also useful provided they do not act as catalyst poisons under the reaction conditions selected. |0032] Substituted aromatic compounds which can be alkylated herein must possess at least one hydrogen atom directly bonded to the aromatic nucleus. The aromatic rings can be substituted with one or more alkyl, aryl, alkaryl, alkoxy, aryloxy, cycloalkyl, halide, and/or other groups which do not interfere with the alkylation reaction.

{0033] Suitable aromatic hydrocarbons include benzene, toluene, xylene, naphthalene, anthracene, naphthacene, perylene, coronene and phenanthrene. [0034] Generally the alkyl groups which can be present as substituents on the aromatic compound contain from 1 to about 22 carbon atoms and preferably from about 1 to 8 carbon atoms, and most preferably from 1 to 4 carbon atoms. [0035] By way of example, suitable alkyl substituted aromatic compounds include toluene, xylene, isopropylbenzene, normal propylbenzene, alpha- methylnaphthalene, ethylbenzene, cumene, mesitylene, durene, p-cymene, butylbenzene, pseudocumene, o-diethylbenzene, m-diethylbenzene, p- diethylbenzene, isoamylbenzene, isohexylbenzene, pentaethylbenzene, pentamethylbenzene; 1 ,2,3,4-tetraethylbenzene; 1 ,2,3,5-tetramethylbenzene; 1,2,4-triethylbenzene; 1 ,2,3-trimethylbenzene, m-butyltoluene; p-butyltoluene; 3,5-diethyltoluene; o-ethyltoluene; p-ethyltoluene; m-propyltoluene; 4-ethyl-m- xylene; dimethylnaphthalenes; ethylnaphthalene; 2,3-dimethylanthracene; 9- ethylanthracene; 2-methylanthracene; o-methylanthracene; 9,10- dimethylphenanthrene; and 3-methyl-phenanthrene.

{0036] The alkylating agent employed in the alkylation step of the present process can be any olefin capable of reacting with an alkylatable aromatic species, including any olefin having from 2 to 6 carbon atoms, including by way of example, ethylene, propylene, any butene, any pentene, and any hexene, including cyclic olefins, such as cyclohexene.

[0037] In particular, the present alkylation process is directed to the production of cumene, sec-butylbenzene or a mixture thereof by the alkylation of benzene with propylene and/or a linear butene (for example 1 -butene and/or 2- butene). The benzene employed in such a process can be any commercially available benzene feed, but preferably the benzene has a purity level of at least 99 wt%. Similarly, the alkylating agent can be pure (at least 99% purity) propylene and/or linear butane or alternatively can be an olefinic C ₃ and/or C ₄ hydrocarbon mixture 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. {0038] For example, the following C ₄ 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

[0039] Other refinery mixed C ₄ 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-bυtane = 5-25 wt%

[0040] C ₄ hydrocarbon fractions obtained from the conversion of oxygenates, such as methanol, to lower olefins more typically have the following composition:

Propylene = 0-l 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%

(0041) Any one or any mixture of the above C ₄ 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 products of isobutene with benzene are tert-butylbenzene and iso- butylbenzene which, as previously stated, act as inhibitors 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.

|0042] In addition to other hydrocarbon components, commercial C ₄ hydrocarbon mixtures typically contain other impurities which could be detrimental to the alkylation process. For example, refinery C ₄ hydrocarbon

streams typically contain nitrogen and sulfur impurities, whereas C ₄ hydrocarbon streams obtained by oxygenate conversion processes 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.

|0043] It is also possible to employ a mixture of a C ₄ alkylating agent, as described above, and C ₃ 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 reduction, 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. [0044] Conveniently, the total feed to the alkylation step of the present invention contains less than 1000 wt ppm, such as less than 500 ppm, for example less than 100 ppm, water. In addition, the total feed typically contains less than 100 wt ppm, such as less than 30 ppm, for example less than 3 ppm, sulfur and/or less than 10 wt ppm, such as less than 1 ppm, for example less than 0.1 ppm, nitrogen.

[0045] The alkylation catalyst used in the present process is zeolite beta or 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.

[0046] 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 the incident radiation and a diffractometer equipped with a scintillation counter and associated computer as the collection system.

[0047] 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 MCM-22,

MCM-49, MCM-56 and isotypes of MCM-22, MCM-49 and MCM-56, such as ITQ-2.

[0048] 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 for-example -between 2 and 80 wt% sieve. [0049J 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 in a suitable reaction zone such as, for example, in a flow reactor containing a fixed bed of the catalyst composition or in a catalytic distillation reactor, under effective alkylation conditions. Typically, the alkylation conditions include a temperature of from about 60°C to about 260°C, for example between about 100°C and about 200°C, and/or a pressure of 7000 kPa or less, for example from about 1000 to about 3500 kPa, and/or a weight hourly space velocity (WHSV) based on the olefinic alkylating agent of between about 0.1 and about 50 hr ^"1 , for example between about 1 and about 10 hr ^"1 and/or a molar ratio of aromatic compound to alkylating agent of from about 1 : 1 to about 50: 1 , for example from about 2: 1 to about 10:1, preferably from about 4: 1 to about 9: 1. Preferably, the olefinic alkylating agent is introduced to the reaction in stages, for example by providing the alkylation catalyst in a plurality of reaction zones connected in series and dividing the alkylating agent into a plurality of equal or different aliquot portions, each of which is fed to a different reaction zone. Most or all of the aromatic compound is typically fed to the first reaction zone.

[0050] The reactants can be either in the vapor phase or partially or completely in the liquid phase or under supercritical conditions 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

[00511 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

the desired monoalkylated aromatic species, such as cumene and/or sec- butylbenzene. However, the effluent from the alkylation reaction will normally contain some polyalkylated products and, as will be discussed below, certain olefin oligomers, in addition to unreacted benzene and the desired monoalkylated species. The unreacted aromatic is normally recovered by distillation and recycled to the alkylation reactor. -The bottoms from the aromatic distillation column 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 aromatic compound to maximize the production of the desired monoalkylated species. [0052] Transalkylation with additional aromatic compound 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 independently or in combination of any two or more thereof: a temperature of 100 to 300 ⁰ C, a pressure of 1000 to 7000 kPa; a weight hourly space velocity of 1 to 50 hr ^"1 on total feed, and an aromatic/polyalkylated aromatic weight ratio of 1 to 10.

Removal of Olefin Oligomers

[0053] As stated above, the effluent from the alkylation reaction will normally contain olefin oligomers, which can have a deleterious effect on

downstream reactions. For example, in the alkylation of benzene with propylene and/or linear butenes, these oligomers have now been found to inhibit subsequent oxidation of the cumene and/or sec-butyl benzene to the corresponding hydroperoxide. Moreover, although. distillation is effective to remove some of these impurities, certain oligomers, particularly the C ₁₂ olefins in the case of alkylation of benzene with linear-- butenes,- tend to boil at or near the same temperature as the alkylaromatic product and hence cannot be readily removed by distillation. Thus the present process employs an additional treatment step, namely reduction in the presence of a rhodium-containing catalyst, to reduce the level of oligomers in the alkylation effluent, typically to less than 1 wt %, preferably less than 0.7 wt%, and most preferably less than 0.5 wt%. [0054] The catalyst employed in the additional treatment step can comprise rhodium metal but more preferably comprises a rhodium complex, such as a rhodium halide, for example rhodium chloride. In one embodiment, the catalyst employed in the treating (b) also comprises a phase transfer agent, such as a quaternary ammonium compound, to facilitate phase boundary crossing between the aqueous phase containing the rhodium catalyst and organic phase containing the alkylaromatic compound.

[0055] Conveniently, the reductive treatment is conducted at a temperature of about 0°C to about 300°C and/or a pressure of about 15 to about 1000 kPa and/or a hydrogen to hydrocarbon mole ratio of about 1 : 1000 to about 1000:1. In this way, using the rhodium-containing catalyst, preferably at least 70 wt%, more preferably at least 80 wt%, of the oligomers in the alkylation effluent can be hydrogenated; and independently or in combination, no more than 5 wt%, preferably no more than 2 wt%, of the desired alkylbenzene compounds are hydrogenated.

Oxidation of the Alkylaromatic Compound

[0056] In one embodiment of the present process, where the products of the alkylation step comprise cumene and/or sec-butylbenzene, the products are employed as intermediates in the production of phenol by the Hock process, in which the cumene and/or sec-butylbenzene are initially oxidized to the

corresponding hydroperoxide. This may be accomplished by introducing an oxygen-containing gas, such as air, into a liquid phase containing the alkylbenzene. In the case of cumene, oxidation can readily be effected in the absence of a catalyst, but atmospheric air oxidation of sec-butyl benzene in the absence of a catalyst is very difficult to achieve. For example, at 1 10 ⁰ C 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. [0057] 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.

[0058] 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 ₅ N ¹ - 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-1,2- dicarboximide, N-hydroxy-cis-4-cyclohexene- 1 ,2 dicarboximide, N- hydroxynaphthalimide sodium salt or N-hydroxy-o-benzenedisulphonimide. Preferably, the catalyst is Nrhydroxyphthalimide. Another suitable catalyst is N,N',N"-thihydroxyisocyanuric acid.

[0059] - 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. [0060] Suitable conditions for the oxidation step include a temperature between about 20°C and about 200°C, such as about 50 ⁰ C to about 130 ⁰ C, and/or a pressure of 50 to 2000 kPa (about 0.5 to 20 atmospheres). 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 hydroperoxide produced may be concentrated by distilling off the unreacted alkylbenzene prior to the cleavage step.

[0061] By conducting the rhodium reduction step prior to the oxidation step, it is found that that the degree of conversion of the cumene and/or sec-butylbenzene to the corresponding hydroperoxide in the subsequent oxidation process is significantly increased.

Hydroperoxide Cleavage

[0062] The final step in the conversion of the cumene and/or sec-butylbenzene into phenol and acetone and/or methyl ethyl ketone involves cleavage of the hydroperoxide. This 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 ⁰ C to about 12O ⁰ C and/or a pressure of about 50 to about 2500 kPa, such as about 100 to about 1000 kPa and/or 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 . To assist in heat removal, hydroperoxide is preferably

diluted in an organic solvent inert to the cleavage reaction, such as methyl ethyl ketone, acetone, phenol, cumene or sec-butylbenzene. The cleavage reaction is conveniently conducted in a catalytic distillation unit.

(0063] The catalyst. employed in the cleavage step can be a homogeneous catalyst or a heterogeneous catalyst.

[0064] ~- 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,

|0065] 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. [0066] The following Examples are given for illustrative purposes and do not limit the scope of the invention.

Example 1

Sec-Butylbenzene Production Using MCM-22 Catalyst and 2-Butene Feed

[0067] A 1.0 gram sample of MCM-22 catalyst (65 % MCM-22/35% alumina binder) was used for the alkylation of benzene with 2-butene. The catalyst was in the form of -a 1.6 mm (1/16") diameter cylindrical extrudate, chopped to 1.6 mm (1/16") length, and was diluted with sand to 3 cc and loaded into an isothermal, down-flow, fixed-bed, tubular reactor having an outside diameter of 4.76mm (3/16"). The catalyst was dried at 150 ⁰ 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 2068 kPag (300 psig). Benzene flow was then reduced to 7.63 cc/hr (6.67 WHSV) and a 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 (1.6 WHSV). Feed benzene/butene molar ratio was maintained at 3: 1 for the entire run and the reactor temperature was adjusted to 160 ⁰ C. Liquid products were

collected at reactor conditions of 160°C and 2068 kPag (300 psig) in a cold-trap and analyzed off line. 2-Butene conversion was determined by measuring unreacted 2-butene relative to feed 2-butene. The catalyst was on stream for 4 days at 1.6 WHSV of butene with 97% 2-butene conversion, 2 days at 4.8 WHSV with 95% conversion, then 1 day at 7.2 WHSV with 86% conversion, and followed by 4-daysagairπat 1.6 WHSV with 97% conversion. Representative data are shown in Table 1.

Table 1. sec-Butylbenzene Production with MCM-22 and 2-Butene Feed

Days on Stream 3.8 5.9 7.1 10.8

Butene WHSV, h ^" ' 1.6 4.8 7.2 1.6

2-Butene Conv, % 97.7 95.3 86.0 97.2

Product Selectivity, wt %

Iso-Butane 0.010 0.001 0.004 0.008

Iso-Butene & 1 -Butene 0.000 0.020 0.355 0.000

C ₅ -C7 compounds 0.227 0.105 0.132 0.120

C ₈ and Cu (butene oligomers) 0.812 1.753 2.556 1.910

Cumene 0.077 0.050 0.031 0.059 t-Butylbenzene 0.158 0.060 0.026 0.103 iso-Butylbenzene* 0.000 0.000 0.000 0.000 sec-Butylbenzene 89.185 90.983 90.490 91.553 n-Butylbenzene 0.024 0.031 0.030 0.025

Di-butylbenzene 8.012 6.589 5.982 5.791

Tri-butylbenzene 1.239 0.420 0.392 0.417

Heavies 0.256 0.008 0.003 0.013

Sum 100.0 100.0 100.0 100.0

Burylbenzene Composition, % t-Butylbenzene 0.177 0.065 0.029 0.1 12 iso-Butylbenzene* 0.000 0.000 0.000 0.000 sec-Butylbenzene 99.796 99.900 99.938 99.860 n-Butylbenzene 0.027 0.034 0.033 0.028

Sum 100.0 100.0 100.0 100.0

All samples collected at 160°C, 2068 kPag (300 psig), and 3: 1 benzene/butene molar ratio.

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

Example 2

Cumene Production Using MCM-49 Catalyst and Propylene Feed

[0068] A 0.5g sample of fresh MCM-49 catalyst with a nominal composition of 80% zeolite and 20% Versal 300 alumina, extruded to 1.6 mm (1/16 inch) cylinder form, was used for the alkylation of benzene with propylene. The

catalyst was dried at 26O ⁰ C for a minimum of 2 hours before testing. The catalyst sample (containing 0.4 grams of zeolite) was loaded between two 0.6 cm (0.25- inch) thick layers of inert, 8-grit quartz particles that had previously been dried at 121°C until loaded into the stationary sample basket. 156.1 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 N ₂ to ensure the elimination of air from the head space. The batch reactor was then pressured to about 1480 kPa (200 psig) with N ₂ to ensure proper sealing and absence of leaks. Pressure was reduced to about 445 kPa (50 psig) and N ₂ at a pressure of about 790 kPa (100 psig) was used to quantitatively deliver 28.1 grams of reagent grade propylene from a transfer vessel into the batch reactor. The benzene to propylene ratio was 3: 1 by mole. [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 130°C in about 20 minutes using a programmable autoclave controller to maintain constant ramp rate and temperature. After reaching temperature, reactor pressure was increased to 2170 kPa (300 psig) by adding more N ₂ to the system. Reaction time-zero was recorded from the point at which temperature and pressure targets [130 ⁰ C, 2068 kPag (300 psig)] were attained and stable. The reaction period for this evaluation was 3 hours. 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 a flame ionization detector (FID). Propylene conversion was 100% and benzene conversion was 33%.

Example 3

Hydrogenation of Commercially Available Sec-Butylbenzene with Rhodium

[0070] Into a lOOcc Parr autoclave were added sec-butylbenzene from TCI (51.8g, 0.3864 mole), rhodium trichloride hydrate from Engelhard (0.52g, 0.0025 mole) and trioctyl methyl ammonium chloride (Aliquat®336) from Aldrich Chemical Co. (0.52g, 0.001286 mole). The autoclave was reassembled, leak

tested with nitrogen, then pressurized to 348 kPag (50 psig) with hydrogen. The hydrogen was vented and refilled with hydrogen to remove any nitrogen. The contents of the autoclave were stirred at room temperature (22-16°C) overnight for 19 hours. The hydrogen pressure in the autoclave was maintained at 348 kPag (50 psig) throughout the reaction period. The clear red liquid reaction mixture was removed -from the autoclave, washed with 2 x lOOcc of distilled water, dried over 5 grams of 5A molecular sieve, then distilled with a Claissen adapter. The clear and colorless liquid sec-butylbenzene was collected at a boiling point of IO8°C/14 kPa (105 mm Hg) vacuum for oxidization in a separate experiment (see Example 1 1).

Example 4

Hydrogenation of Sec-Butylbenzene from Example 1 with Rhodium

(0071] The procedure of Example 3 was repeated but using the sec- butylbenzene produced in Example 1.

Example 5

Hydrogenation of Cumene from Example 2 with Rhodium

[0072] Two batch runs were completed following the procedure in Example 3. In both runs cumene from batch alkylation experiments as described in Example 2 (51.8g, 0.432 mole), rhodium trichloride hydrate from Engelhard (0.52g, 0.0025 mole) and trioctyl methyl ammonium chloride (Aliquat®336) from Aldrich Chemical Co. (0.52g, 0.001286 mole) were added to the lOOcc Parr autoclave. The run times for each experiment were 16 and 23 hours and the reaction products were combined, washed with 2 x 1 OOcc of distilled water, dried over 10 grams molecular sieve, then distilled with a Claissen adapter. The clear and colorless liquid cumene was collected at a boiling point of 46°C/10.9 kPa (82 mm Hg) vacuum for oxidization in a separate experiment (see Example 19).

Example 6

Hydrogenation of Commercially Available Sec-Butylbenzene with Rhodium

[0073] The procedure of Example 3 was repeated, but using 1 wt% rhodium on activated carbon powder from Alfa (0.52g) as the catalyst. GC/MS analysis

showed that less than 5 wt% of sec-butylbenzene was hydrogenated to sec-butyl cyclohexene and sec-butyl cyclohexane.

Example 7

Hydrogenation of Sec-Butylbenzene from Example 1 with Palladium

[0074] Into a lOOcc Parr autoclave were added sec-butylbenzene from Example ^' 1 ^" (55.4g, 0.4134 mole), 0.5% palladium on alumina (20/40 mesh) (2.0 grams) from Aldrich Chemical Co. and Amberlyst 35 bead (5.0 gram) from Rohm & Haas. The autoclave was reassembled, leak tested with nitrogen, then pressurized to 348 kPag (50 psig) with hydrogen. The hydrogen was vented and refilled with hydrogen to remove any nitrogen. The contents of the autoclave were stirred at room temperature (22-16°C) overnight for 19 hours. The hydrogen pressure in the autoclave was maintained at 348 kPag (50 psig) throughout the reaction period. The clear red liquid reaction mixture was removed from the autoclave, washed with 2 x lOOcc of distilled water, dried over 5 grams of 5 A molecular sieve, then distilled with a Claissen adapter. The clear and colorless liquid sec-butylbenzene was collected at a boiling point of 108°C/14 kPa (105 mm Hg) vacuum for oxidization in a separate experiment (see Example 14).

Example 8

Hydrogenation of Sec-Butylbenzene from Example 1 with Palladium

[0075] The procedure of Example 7 was repeated but using 43.2g (0.322 mole) of the sec-butylbenzene from Example 1 and with the Amberlyst 35 bead being omitted.

Example 9

Hydrogenation of Sec-Butylbenzene from Example 1 with Palladium

[0076] Into a l OOcc Parr autoclave were added sec-butylbenzene from Example 1 (47.47g, 0.3542 mole), and 1% palladium on alumina powder from Aldrich Chemical Co. (1.6 grams). The autoclave was reassembled, leak tested with nitrogen, then pressurized to 348 kPag (50 psig) with hydrogen. The hydrogen was vented and refilled with hydrogen to remove any nitrogen. The stirred contents of the autoclave were heated to 100 ⁰ C in approximately 20

minutes and the temperature maintained at 100 ⁰ C for 3 hours. The hydrogen pressure in the autoclave was maintained at 414 kPag (60 psig) throughout the reaction period. The clear and colorless liquid reaction mixture was removed from the autoclave and filtered. This experiment was repeated and the products combined for oxidization in a separate experiment (see Example 17).

Example 10

Oxidation of Commercially Available Sec-Butylbenzene

[0077) Into a lOOcc Parr autoclave were added sec-butyl benzene from TCI (43.15g, 0.322 mole) and n-hydroxyphthalimide (NHPI) (0.185g, 0.001 135 mole) from Aldrich Chemical Co. The autoclave was reassembled, leak tested with nitrogen, then reattached to the system. The contents were pressurized with nitrogen followed by oxygen to obtain an 80:20 mixture to 1482 kPag (215 psig) at room temperature. The contents of the autoclave were heated to 1 15°C with stirring and a pressure of 1724 kPag (250 psig) resulted. At temperature the oxygen concentration was maintained at approximately 20% throughout the 6 hour heating period by refilling with pure oxygen. Gas samples were taken throughout the heating period to maintain approximately 20% oxygen. At the completion of the run, the contents were cooled to room temperature. At room temperature the liquid product was removed from the autoclave and sampled for gas chromatography. The results are shown in Figure 1 , from which it will be seen that about 22 wt% of the sec-butylbenzene was converted to the corresponding hydroperoxide.

Example 11

Oxidation of Commercially Available Sec-Butylbenzene after Hydrogenation with Rhodium

[0078] The hydrogenation product of Example 3 was oxidized following the procedure of Example 10, except the following quantities were used: sec- butylbenzene (36.25g, 0.2705 mole) and NHPI (0.155g, 0.00095 mole). The results are shown in Figure 1 , from which it will be seen that the rate of conversion of the sec-butylbenzene to the corresponding hydroperoxide was

increased to about 27 wt% (compared to 22 wt% for the unhydrogenated material used in Example 10) by the hydrogenation with the rhodium catalyst.

Example 12

Oxidation of Sec-Butylbenzene of Example 1

J0079] The product of Example 1 was oxidized following the procedure of Example 10, except the following quantities were used: sec-butylbenzene (4 Ig, 0.306 mole) and NHPI (0.176g, 0.001 1 mole). The results are shown in Figure 1 , from which it will be seen that about 14 wt% of the sec-butylbenzene was converted to the corresponding hydroperoxide.

Example 13

Oxidation of Sec-Butylbenzene of Example 1 after Hydrogenation with

Rhodium

[0080] The hydrogenation product of Example 4 was oxidized following the procedure of Example 10, except the following quantities were used: sec- butylbenzene (4 Ig, 0.306 mole) and NHPI (0.176g, 0.0011 mole). The results are shown in Figure 1 , from which it will be seen that the rate of conversion of the sec-butylbenzene to the corresponding hydroperoxide was increased to about 27 wt% (compared to 14 wt% for the unhydrogenated material used in Example 12) by the hydrogenation with the rhodium catalyst.

Example 14

Oxidation of Sec-Butylbenzene of Example 1 after Hydrogenation with

Palladium

[0081] The hydrogenation product of Example 7 was oxidized following the procedure of Example 10, except the following quantities were used: sec- butylbenzene (37.0g, 0.2761 mole) and NHPI (0.16g, 0.00098 mole). The results are shown in Figure 2, from which it will be seen that, although the rate of oxidation of the sec-butylbenzene was increased to 16 wt% by the hydrogenation with the palladium catalyst (compared to 14 wt% for the unhydrogenated material used in Example 12), the amount of the increase was significantly less than that obtained with the rhodium catalyst used in Example 13.

Example 15

Oxidation of Sec-Butylbenzene of Example 1 after Hydrogenation with

Palladium

[0082] The hydrogenation product of Example 8 was oxidized following the procedure of Example 10, except the following quantities were used: sec- butylbenzene (38.84g, 0.2898 mole) and NHPI (0.167g, 0.00103 mole). The results are shown in Figure 2, from which it will be seen that, although the rate of oxidation of the sec-butylbenzene was increased to 17 wt% by the hydrogenation with the palladium catalyst (compared to 14 wt% for the unhydrogenated material used in Example 12), the amount of the increase was again significantly less than that obtained with the rhodium catalyst used in Example 13.

Example 16

Oxidation of Commercially Available Sec-Butylbenzene after Hydrogenation with Rhodium

[0083] The hydrogenation product of Example 6 was oxidized following the procedure of Example 10, except the following quantities were used: sec- butylbenzene (34.52g, 0.2576 mole) and NHPI (0.148g, 0.00091 mole). The results are shown in Figure 2, from which it will be seen that the rate of oxidation of the sec-butylbenzene was only about 15 wt%, as compared with 22 wt% for the unhydrogenated material used in Example 10 and 27 wt% for the hydrogenated product used in Example 1 1. In this case, the conversion of some of the sec- butylbenzene to sec-butyl cyclohexene and sec-butyl cyclohexane during the hydrogenation step resulted in a significant decrease in the oxidation activity of the hydrogenation product.

Example 17

Oxidation of Sec-Butylbenzene of Example 1 after Hydrogenation with

Palladium

[0084] The hydrogenation product of Example 9 was oxidized following the procedure of Example 10. The results are shown in Figure 2, from which it will be seen that the rate of oxidation of the sec-butylbenzene was about 14 wt%,

which is substantially the same as that for the unhydrogenated material used in Example 12.

Example 18

Oxidation of Cumene of Example 2

[0085] Cumene from Example 2 (34.6g, 0.288 mole) was oxidized following the same procedure as Example 10, except no n-hydroxyphthalimide (NHPI) was added in this experiment. The results are shown in Figure 3, from which it will be seen that about 26 wt% of the cumene was converted to the corresponding hydroperoxide.

Example 19

Oxidation of Cumene of Example 2 after Hydrogenation with Rhodium

[0086] The hydrogenated product of Example 5 was oxidized following the same procedure as Example 18. The results are shown in Figure 3, from which it will be seen that hydrogenation of the cumene product using a rhodium catalyst increased conversion of the cumene to the corresponding hydroperoxide to about 33 wt%.

[0087] 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.