More than about thirty years ago, many household laundry detergents were made of branched alkylbenzene sulfonates (BABS). BABS are manufactured from a type of alkylbenzenes called branched alkylbenzenes (BAB). Alkylbenzenes (phenyl-alkanes), refer to a general category of compounds having an aliphatic alkyl group bound to a phenyl group and having the general formula of (mi-alkyli) i-n-phenyl-alkane. The aliphatic alkyl group consists of an aliphatic alkyl chain, which is referred to by"alkane"in the (mI-alkyli) i-n-phenyl-alkane formula. Of the chains of the aliphatic alkyl group, the aliphatic alkyl chain is the longest straight chain that has a carbon bound to the phenyl group. The aliphatic alkyl group may also consist of one or more alkyl group branches, each of which is attached to the aliphatic alkyl chain and is designated by a corresponding" (mi-alkyli) i" in the (mi-alkyli) i-n-phenyl-alkane formula.

The characteristics of BAB are described in US-A-6,187, 981 B1. Briefly, BAB has a relatively large number of primary carbon atoms per aliphatic alkyl group, the phenyl group in BAB can be attached to any non-primary carbon atom of the aliphatic alkyl chain, and there is a relatively high probability that one of the carbons of the aliphatic alkyl group of BAB is a quaternary carbon.

When a carbon atom on the alkyl chain is attached to two other carbons on the alkyl side chain, a carbon atom of an alkyl group branch and a carbon atom of the phenyl group, the resulting alkyl-phenyl-alkane is referred to as a"quaternary alkyl-phenyl-alkane"or simply a <BR> <BR> "quat. "Thus, quats comprise alkyl-phenyl-alkanes having the general formula m-alkyl-m- phenyl-alkane. If the quaternary carbon is the second carbon atom from an end of the alkyl <BR> <BR> side chain, the resulting 2-alkyl-2-phenyl-alkane is referred to as an"end quat. "Any other quaternary carbon along the alkyl side chain is referred to as an"internal quat." Thirty years ago the pollution of rivers and lakes by laundry detergents made of BABS.

Making detergents from linear alkylbenzene sulfonates (LABS), which biodegrade more rapidly than BABS, solved this problem. LABS are manufactured from alkyl benzenes called

linear alkylbenzenes (LAB). US-A-6,187, 981 B1 describes LAB. LAB has a linear aliphatic alkyl group with two primary carbon atoms, and the phenyl group in LAB is usually attached to any secondary carbon atom of the linear aliphatic alkyl group.

Recently research has identified certain modified alkylbenzene sulfonates, which are referred to herein as MABS. MABS differ in composition from BABS and LABS alkylbenzene sulfonates and have improved laundry cleaning performance, hard surface cleaning performance, and excellent efficiency in hard water, while also having biodegradability comparable to LABS. Sulfonating modified alkylbenzenes (MAB) will produce MABS. MAB is a phenyl-alkane comprising a lightly branched aliphatic alkyl group and a phenyl group and has the general formula (mi-alkyli) i-n-phenyl-alkane. MAB usually has two, three, or four primary carbons, contains a high proportion of 2-phenyl-alkanes, and has a relatively low proportion of internal quats. US-A-6,187, 981 Bl discloses a process for producing MAB by paraffin isomerization, paraffin dehydrogenation, and alkylation, with paraffin recycle. US-A-5,276, 231 describes a process for making LAB with selective removal of aromatic by-products of a paraffin dehydrogenation zone and also discloses recycling paraffins to the dehydrogenation zone, selective hydrogenation of any monoolefins in the paraffin recycle stream, and selective hydrogenation of diolefinic by-products from the dehydrogenation zone.

For other alkylation processes and adsorptive separation processes that produce uniquely lightly branched or delinearized alkylbenzenes, see PCT International Publication Nos. WO 99/05082, WO 99/05084,99/05241, WO 99/05243, and W099/07656, which are hereby incorporated herein by reference.

Because of the advantages of MABS over other alkylbenzene sulfonates, catalysts and processes are sought that selectively produce MAB with a desired selectivity to 2-phenyl- alkanes and to internal quaternary phenyl-alkanes.

SUMMARY OF THE INVENTION A process for the production of phenyl-alkanes, in particular modified alkylbenzenes (MAB), by the steps of paraffin dehydrogenation, olefin isomerization, and alkylation of a phenyl compound, in which paraffins in the alkylation effluent are recycled to the dehydrogenation step, is disclosed. The paraffins that are recycled may be linear or nonlinear paraffins, including lightly branched paraffins. Because the recycled paraffins can be converted into lightly branched olefins, this process efficiently recovers paraffins in the

alkylation effluent and uses them to produce valuable phenyl-alkane products. This process thus increases the yield of valuable products for a given amount of paraffinic feedstock charged to the process while avoiding the difficulty of separating the paraffins from the monoolefins after the paraffin dehydrogenation step and prior to the alkylation step.

This process, when used for detergent alkylation, produces detergents that meet the increasingly stringent requirements of 2-phenyl-alkanes selectivity and internal quaternary phenyl-alkane selectivity for the production of modified alkylbenzenes (MAB). Thus, sulfonating the MAB produces modified linear alkylbenzene sulfonates (MABS) with improved cleaning effectiveness in hard and/or cold water and biodegradability comparable to that of linear alkylbenzene sulfonates.

It is believed that the MAB and MABS produced by the processes disclosed herein are not the products produced by the prior art processes that do not recycle paraffins and that in the dehydrogenation zone the extent of conversion of branched paraffins can exceed that of normal (linear) paraffins, and/or that the extent of conversion of heavier paraffins can exceed that of lighter paraffins. In this case, since equilibrium limits the extent of paraffin conversion, the dehydrogenation zone effluent can contain more linear and/or lighter paraffins. Thus, the concentration of linear paraffins and/or lighter paraffins in the recycle paraffin stream can increase. This, in turn, can increase the concentration and ultimately the conversion of linear and/or lighter paraffins in the dehydrogenation zone until the rate of removal from the process of linear and/or lighter paraffins via dehydrogenation and subsequent alkylation equals the rate of introduction into the dehydrogenation zone of those paraffins from the paraffin feedstock and the recycle paraffin stream. Accordingly, for a given extent of olefin conversion in the alkylation zone, the aliphatic alkyl chain of the MAB product of the present invention will retain more carbon number similarity to the paraffinic feedstock than that of the prior art processes. The prior art processes skew the distribution of the number of carbon atoms in the aliphatic alkyl groups of the MAB to higher carbon numbers compared to that of the present invention. On sulfonation, the MABS products of the present invention tend to retain a similar carbon number distribution of the aliphatic alkyl chain to that of the paraffinic feedstock.

Thus, for a given combination of feedstocks, the processes of this invention can produce particular MAB and MABS products having aliphatic alkyl chain with specially tailored extents of branching that can differ from those of the prior art processes.

DETAILED DESCRIPTION OF THE INVENTION Two feedstocks consumed in the subject process are a paraffinic compound and a phenyl compound. The paraffinic feedstock may comprise nonbranched (linear) or normal paraffin molecules having a total number of carbon atoms per paraffin molecule of from 8 to 28, and in other embodiments from 8 to 15, from 10 to 15, and from 11 to 13 carbon atoms.

Two carbon atoms per nonbranched paraffin molecule are primary carbon atoms and the remaining carbon atoms are secondary carbon atoms.

In addition to nonbranched paraffins, other acyclic compounds may be charged to the subject process. These other acyclic compounds may be charged to the subject process either in the paraffinic feedstock containing nonbranched paraffins, or via one or more other streams that are charged to the subject process. One such acyclic compound is a lightly branched paraffin, which as used herein, refers to a paraffin having a total number of carbon atoms of from 8 to 28, of which three or four of the carbon atoms are primary carbon atoms and none of the remaining carbon atoms are quaternary carbon atoms. The lightly branched paraffin may have a total number of from 8 to 15 carbon atoms, and in another embodiment from 10 to 15 carbon atoms, and in yet another embodiment from 11 to 13 carbon atoms. The lightly branched paraffin generally comprises an aliphatic alkane having the general formula of (pi- alkyli) i-alkane. The lightly branched paraffin consists of the longest straight chain of the lightly branched paraffin an aliphatic alkyl chain, referred to as"alkane"in the (pi-alkyli) i-alkane formula. The lightly branched paraffin also consists of one or more alkyl group branches designated by a corresponding" (pi-alkyli) i" with the subscript"i"equal to the number of alkyl group branches and each corresponding alkyl group branch attached to carbon number pi of the aliphatic alkyl chain. The aliphatic alkyl chain is numbered from one end to the other in a direction being that gives the lowest numbers possible to the carbon atoms having alkyl group branches.

The alkyl group branch or branches of the lightly branched paraffin may be selected from methyl, ethyl, and propyl groups, with shorter and normal branches preferred. Lightly branched paraffins having either two alkyl group branches or four primary carbon atoms may comprise less than 40 mol-%, and in another embodiment less than 25 mol-%, of the total lightly branched paraffins. Lightly branched paraffins having either one alkyl group branch or three primary carbon atoms may comprise more than 70 mol-% of the total lightly branched monoolefins. Any alkyl group branch can be bonded to any carbon on the aliphatic alkyl chain.

The feed to the process may include more highly branched paraffins than the lightly branched paraffins. However, on dehydrogenation such highly branched paraffins tend to form highly branched monoolefins which on alkylation tend to form BAB. For example, paraffin molecules consisting of at least one quaternary carbon atom tend on dehydrogenation followed by alkylation to form phenyl-alkanes with quaternary carbon atoms without the phenyl group.

Preferably the charging of these highly branched paraffins charged to the process is minimized.

The paraffin molecules on mol basis containing at least one quaternary carbon atom in the paraffinic feedstock or all the paraffins charged to the process typically comprise less than 10%, preferably less than 5%, more preferably less than 2%, and most preferably less than 1%.

The paraffinic feedstock is normally a mixture of linear and lightly branched paraffins having different carbon numbers. Any suitable method for producing the paraffinic feedstock may be used. One method produces the paraffinic feedstock by separation of nonbranched (linear) hydrocarbons or lightly branched hydrocarbons from a kerosene boiling range petroleum fraction. Proven commercial processes for such separation are UOP's Mole process for the liquid-phase adsorptive separation of normal paraffins from isoparaffins and cycloparaffins and UOP's Kerosene Isosiv Process, for vapor-phase adsorptive separation of normal paraffins from nonnormal paraffins. The feed streams to these above-mentioned separation processes comprise branched paraffins that are more highly branched than the lightly branched paraffins.

Well-known analytical methods in the art of gas chromatography can determine the composition of such mixtures of linear, lightly branched, and branched paraffins for the paraffinic feedstock or the feed stream to the above-mentioned adsorption separation processes.

H. Schulz, et al. starting at page 315 of Chromatographia 1,1968, describes a suitable temperature-programmed gas chromatograph method for identifying components in complex mixtures of paraffins.

For detergent alkylation the phenyl compound of the phenyl feedstock comprises benzene. The phenyl compound of the phenyl feedstock may be alkylated or otherwise substituted derivatives of higher molecular weight than benzene, including toluene, ethylbenzene, xylene, phenol, naphthalene, etc. , but the these alkylation products may be less suitable detergent precursors than alkylated benzenes.

The subject process may be divided into a dehydrogenation section, an isomerization section, and an alkylation section. This invention is not limited to any one particular flow

scheme for the dehydrogenation section. The dehydrogenation section may be configured substantially in the manner described in US-A-6,187, 981 Bl. Any suitable dehydrogenation catalyst may be used. The catalyst may be a layered composition comprising an inner core and an outer layer bonded to the inner core, where the outer layer comprises a refractory inorganic oxide having uniformly dispersed thereon at least one platinum group (Group VIM (IUPAC 8- <BR> <BR> 10) ) metal and at least one promoter metal, and where at least one modifier metal is dispersed on the catalyst composition. The outer layer is bonded to the inner core to the extent that the attrition loss can be less than 10 wt-% based on the weight of the outer layer. Such a catalyst composition is described in US-A-6,177, 381. The dehydrogenation conditions are selected to minimize cracking and polyolefin byproducts.

Although it may occur at dehydrogenation conditions, olefin skeletal isomerization in the dehydrogenation section is not a requirement of this invention because olefins are isomerized in the hereinafter-described isomerization section. Reducing the dehydrogenation temperature can minimize skeletal isomerization. Skeletal isomerization at dehydrogenation conditions means isomerization that increases the number of primary carbon atoms of a paraffin or olefin molecule. The monoolefin-containing dehydrogenated product stream from the paraffin dehydrogenation section is typically a mixture of olefins and unreacted paraffins corresponding skeletally to the paraffins charged to the dehydrogenation section. Minimal skeletal isomerization of the paraffins and olefins in the dehydrogenation section means less than 15 mol-%, and preferably less than 10 mol-%, of the paraffins and olefins skeletally isomerize. Thus, it is preferred that when most of the feed paraffins are linear (unbranched), most of the olefins are linear (unbranched) olefins.

The linear monoolefins in the dehydrogenation reaction effluent pass to a skeletal isomerization zone, which decreases the linearity and adjusts the number of primary carbon atoms of the olefin molecules. The skeletal isomerization of the molecule can comprise increasing by 1 or 2 the number of methyl group branches of the aliphatic chain. Because the total number of carbon atoms of the olefin molecule remains the same, each additional methyl group branch causes reduces the aliphatic chain by one carbon number.

The skeletal isomerization step sufficiently decreases the linearity of the dehydrogenation reaction effluent so that after use in alkylation the phenyl-alkane alkylate meets the requirements for primary carbon atoms, 2-phenyl-alkane selectivity, and internal quaternary phenyl-alkane selectivity. Skeletal isomerization of the starting-material olefins can be accomplished in any manner known in the art and with any known catalyst. Suitable

catalysts include ferrierite, ALPO-31, SAPO-11, SAPO-31, SAPO-41, FU-9, NU-10, NU-23, ZSM-12, ZSM-22, ZSM-23, ZSM-35, ZSM-48, ZSM-50, ZSM-57, MeAPO-11, MeAPO-31, MeAPO-41, MeAPSO-11, MeAPSO-31, MeAPSO-41, MeAPSO-46, ELAPO-11, ELAPO-31, ELAPO-41, ELAPSO-11, ELAPSO-31, ELAPSO-41, laumontite, cancrinite, offretite, hydrogen form of stillbite, magnesium or calcium form of mordenite, and magnesium or calcium form of partheite. Suitable MeAPSO-31 catalysts include MgAPSO-31. Many natural zeolites, such as feirierite, that have an initially reduced pore size can be converted to forms suitable for olefin skeletal isomerization by removing associated alkali metal or alkaline earth metal by ammonium ion exchange and calcination to produce the substantially hydrogen form, as taught in US-A-4,795, 623 and US-A-4,924, 027. However, H-form mordenite is not a suitable catalyst for skeletal isomerization of the olefinic starting-material. Catalysts and conditions for skeletal isomerization of the olefinic starting-material are disclosed in US-A- 5,510, 306; US-A-5,082, 956; and US-A-5,741, 759. The skeletal isomerization conditions include conditions under which at least a portion or all of the hydrocarbons contact the skeletal isomerization catalyst in the liquid phase. The isomerization temperature is from 50 to 400°C (122 to 752°F). When the isomerization catalyst contains a Group VIII (IUPAC 8-10) metal the isomerization conditions include a molar ratio of hydrogen per hydrocarbon of greater than 0.01 : 1.

The isomerized product stream for the production of MAB contains a lightly branched monoolefin. A lightly branched monoolefin refers to a monoolefin having a total number of carbon atoms of from 8 to 28, of which three or four of the carbon atoms are primary carbon atoms and none of the remaining carbon atoms are quaternary carbon atoms. The lightly branched monoolefin may have a total number of from 8 to 15 carbon atoms, preferably from 10 to 15 carbon atoms, and more preferably from 11 to 13 carbon atoms. The isomerized product stream has a concentration of lightly branched monoolefins of greater than 25 mol-%.

The lightly branched monoolefin generally comprises an aliphatic alkene having the general formula of (pi-alkyli) i-q-alkene with an the longest straight chain aliphatic alkenyl containing the carbon-carbon double bond referred to by"alkene". The lightly branched monoolefin also consists of one or more alkyl group branches attached to the aliphatic alkenyl chain and designated by a corresponding" (pI-alkyl ;) ;" in the formula. The double bond is between carbon numbers q and (q+ 1) of the aliphatic alkenyl chain. The aliphatic alkenyl chain is numbered from one end in a direction that gives the lowest number to the carbon atoms with the double bond.

The lightly branched monoolefin may be an alpha monoolefin or a vinylidene monoolefin, but is preferably an internal monoolefin. As used herein, the term"alpha olefins" <BR> <BR> refers to olefins having the formula, R-CH=CH2. The term"internal olefins, "as used herein, includes di-substituted internal olefins having formula R-CH=CH-R; tri-substituted internal olefins having the formula R-C (R) =CH-R; and tetra-substituted olefins having the formula R- <BR> <BR> C (R) =C (R) -R. The di-substituted internal olefins include beta internal olefins having the formula R-CH=CH-CH3. As used herein, the term"vinylidene olefins"refers to olefins having the formula R-C (R) =CH2. In the preceding formulas, R is an alkyl group that may be identical to or different from other alkyl group (s) in each formula. Insofar as permitted by the definition of the term"internal olefin", when the lightly branched monoolefin is an internal monoolefin, any two carbon atoms of the aliphatic alkenyl chain may bear the double bond. Suitable lightly branched monoolefins include octenes, nonenes, decenes, undecenes, dodecenes, tridecenes, tetradecenes, pentadecenes, hexadecenes, heptadecenes, octadecenes, nonadecenes, eicosenes, heneicosenes, docosenes, tricosenes, tetracosenes, pentacosenes, hexacosenes, heptacosenes, and octacosenes.

Generally the alkyl group branch or branches of the lightly branched monoolefin are methyl, ethyl, and propyl groups, with shorter and normal branches being preferred.

Preferably, the lightly branched monoolefin has only one alkyl group branch, but two alkyl group branches are also possible. Lightly branched monoolefins having either two alkyl group branches or four primary carbon atoms may comprise less than 40 mol-%, and preferably less than 30 mol-%, of the total lightly branched monoolefins, with the remainder of the lightly branched monoolefins having one alkyl group branch. Lightly branched monoolefins having either one alkyl group branch or three primary carbon atoms may comprise more than 70 mol- % of the total lightly branched monoolefins. US-A-6, 187, 981 describes analytical methods for determining the composition of a mixture of lightly branched monoolefins.

In addition to the lightly branched monoolefin, other acyclic compounds may contact the alkylation catalyst. The isomerized product stream or one or more other streams may bring these other acyclic compounds into contact with the catalyst. Other acyclic compounds include nonbranched (linear) olefins and monolefins, including linear and nonlinear paraffins.

Nonbranched (linear) olefins which may contact the zeolite may have a total number of carbon atoms per paraffin molecule of from 8 to 28 preferably from 8 to 15, and more preferably from 10 to 14 carbon atoms. The nonbranched olefin may be an alpha monoolefin but is preferably an internal monoolefin. When present in the isomerized product stream with the lightly

branched monoolefins, the linear olefin content in the isomerized product stream is preferably less than or equal to 75 mol-% of the total monoolefins and more preferably less than 60 mol- % of the total monoolefins.

Because of the possible presence of linear monoolefins the bulk isomerized product stream may contain, on average, fewer than 3, or between 3 and 4, primary carbon atoms per monoolefin molecule in the isomerized product stream. Depending on the relative proportions of linear and lightly branched monoolefins, the isomerized product stream, or the sum of all the monoolefins that contact the zeolite, may have from 2.25 to 4 primary carbon atoms per monoolefin molecule.

Linear and/or nonlinear paraffins, if any, which may contact the zeolite, via the isomerized product stream or not, may have a total number of carbon atoms per paraffin molecule of from 8 to 28 carbon atom, preferably from 8 to 15 carbon atoms, and more preferably from 10 to 14 carbon atoms. Such linear and nonlinear paraffins are not expected to materially interfere in the alkylation step but to act as a diluent. However, the presence of such diluents in the alkylation reactor generally results in higher volumetric flow rates of process streams that many necessitate larger equipment and more catalyst in the alkylation reaction circuit and larger product recovery facilities. The isomerized product stream preferably does not contain unacceptable concentrations of impurities or poisons which would cause difficulties in the alkylation step. Well-known steps, such as removal by distillation and selective hydrogenation to convert polyolefins to monoolefins can remove some impurities.

When monoalkylating a phenyl compound with a lightly branched olefin, the isomerized product stream preferably contains little if any of the dimer of that particular lightly branched olefin.

The concentration of more highly branched monoolefins than the lightly branched monoolefins in the isomerized product stream is preferably minimized to avoid their conversion because to BAB upon alkylation. For example, the isomerized product stream may contain monoolefin molecules having at least one quaternary carbon atom, which tend on alkylation to form phenyl-alkanes having a quaternary carbon atom that is not bonded with a phenyl portion. Monoolefins having at least one quaternary carbon atom preferably comprise less than 10 mol-%, and more preferably less than 1 mol-%, of the isomerized product stream or of the sum of all the monoolefins that contact the catalyst.

The product of the skeletal isomerization step contains the lightly branched monoolefins and may supply olefins to the alkylation section. Accordingly, the isomerized

product stream may be a mixture largely of unreacted paraffins, linear (unbranched) olefins, and branched monoolefins which typically are in the C8-C28 range, preferably in the Cl-cils range and more preferably in the Cil-culs range. 20 to 60 mol-% of the total monoolefins in the isomerized product stream are linear (unbranched) olefins. The monoalkyl branched olefins in the isomerized product stream are preferably monomethyl-alkenes. The dialkyl branched olefin content of the isomerized product stream, in three embodiments of this invention, is less than 30 mol-%, between 10 mol-% and 20 mol-%, and less than 10 mol-%, of the isomerized product stream. The isomerized product stream can be formed from a portion or an aliquot portion of the product of the skeletal isomerization step. An aliquot portion of the product of the skeletal isomerization step is a fraction of the product of the skeletal isomerization step that has essentially the same composition as the product of the skeletal isomerization step.

Besides olefin isomerization, paraffin skeletal isomerization may also take place in the olefin isomerization section. Any resulting non-linear paraffins in the isomerized product stream pass along with normal (linear) paraffins through the hereinafter described alkylation section and recycle to the dehydrogenation section where they mix with paraffins from the paraffinic feedstock. In the dehydrogenation section, these recycled, non-linear paraffins may or may not be dehydrogenated to monoolefins. These already-isomerized paraffins or as already-isomerized paraffins-turned-olefins, then re-enter the olefin isomerization section where they can undergo further isomerization. Thus, the isomerized product stream contains a mixture of nonlinear paraffins and nonlinear olefins that may result from multiple passes of paraffins through the dehydrogenation, isomerization, and alkylation sections.

The lightly branched monoolefins in the isomerized product stream are reacted with a phenyl compound. The alkylation takes place in an alkylation section consisting of an alkylation reaction zone and an alkylation separation zone. This invention can use any flow scheme for the alkylation section. The alkylation section may be configured substantially in the manner described in US-A-6,187, 981 B1. Any suitable alkylation catalyst may be used.

Alkylation catalysts comprise zeolites having a zeolite structure of BEA, MOR, MTW, and NES. Such zeolites include mordenite, ZSM-4, ZSM-12, ZSM-20, offretite, gmelinite, beta, NU-87, and gottardiite.

It is believed the alkylation conditions produce minimal skeletal isomerization of the lightly branched monoolefin or any other olefins and any paraffins in the isomerized product stream. Minimal skeletal isomerization means that preferably less than 15 mol-%, and more

preferably less than 10 mol-%, of the olefin, the aliphatic alkyl chain, and any reaction intermediate undergoes skeletal isomerization. Thus, alkylation preferably occurs in the substantial absence of skeletal isomerization of the lightly branched monoolefin and the number of primary carbon atoms in the lightly branched monoolefin is the same as the number of primary carbon atoms per phenyl-alkane molecule. Any additional methyl group branching on the aliphatic alkyl chain of the phenyl-alkane product will slightly increase primary carbon atoms in the phenyl-alkane product from the primary carbon atoms in the lightly branched monoolefin. Finally, although the formation of 1-phenyl-alkane is not significant at the alkylation conditions its production will slightly reduce the number of primary carbon atoms in the phenyl-alkane product.

The alkylation of the phenyl compound with the lightly branched monoolefins produces (mi-alkyli) i-n-phenyl-alkanes, where the aliphatic alkyl group has two, three, or four primary carbon atoms per phenyl-alkane molecule. The aliphatic alkyl group may have three primary carbon atoms per phenyl-alkane molecule with more preferably methyl groups at both chain ends. In this embodiment, the alkylation produces monomethyl-phenyl-alkanes. However, it is not necessary that all of the (mi-alkyli) i-n-phenyl-alkanes produced have the same number of primary carbon atoms per phenyl-alkane molecule. From 0 mol-% to 75 mol-% and preferably 0 mol-% to 40 mol-%, of the (mi-alkyli) i-n-phenyl-alkanes produced may have 2 primary carbon atoms per phenyl-alkane molecule. As many as possible and preferably from 25 mol-% to 100 mol-%, of the (mi-alkyli) i-n-phenyl-alkanes produced may have 3 primary carbon atoms per phenyl-alkane molecule. In one embodiment from 0 mol-% to 40 mol-% of the (mi-alkyli) i- n-phenyl-alkanes produced may have 4 primary carbon atoms. Thus, (m-methyl)-n-phenyl- alkanes having only one methyl group branch are preferred and are referred to herein as monomethyl-phenyl-alkanes. The number of primary, secondary, and tertiary carbon atoms per product phenyl-alkane molecule can be determined by high resolution multipulse nuclear magnetic resonance (NMR) spectrum editing and distortionless enhancement by polarization transfer (DEPT), as described in the brochure titled"High Resolution Multipulse NMR <BR> <BR> Spectrum Editing and DEPT, "distributed by Bruker Instruments, Inc. , Manning Park, Billerica, Massachusetts, USA.

The selectivity parameters for the alkylation to 2-phenyl-alkanes and to internal quaternary phenyl-alkanes have been determined in the prior art using two slightly different analytical and computational methods. US-A-6,111, 158 and US-A-6,187, 981 use methods that result in slightly different selectivities. Selectivities determined by the methods of US-A-

6, 111, 158 are referred to hereinafter as simplified selectivities, and selectivities determined by the methods of US-A-6,187, 981 are referred to herein as selectivities (i. e. , without the adjective "simplified"). The alkylation of the phenyl compound with the lightly branched monoolefins has a selectivity of 2-phenyl-alkanes of from 40 to 100 and preferably from 60 to 100 in another embodiment, and an internal quaternary phenyl-alkane selectivity of less than 10 in one embodiment and preferably less than 5.

Quaternary phenyl-alkanes can form by alkylating the phenyl compound with a lightly branched monoolefin having at least one tertiary carbon atom. Depending on the location of the quaternary carbon atom with respect to the ends of the aliphatic alkyl chain, the quaternary phenyl-alkane may be either an internal or an end quat.

At least a portion of the overhead liquid stream of the paraffin column in the alkylation separation zone is recycled to the dehydrogenation section. The recycled portion of the overhead liquid stream may be an aliquot portion of the overhead liquid stream. The process may selectively hydrogenate any diolefins present in the dehydrogenated product stream.

Some of the paraffin column overhead liquid stream may also be recycled to the isomerization section, since the paraffin column overhead liquid stream may contain monoolefins. However, the concentration of monoolefins in the paraffin column overhead liquid stream is generally less than 0.3 wt-%.

The process may selectively remove any aromatic by-products present in the dehydrogenated product stream. The aromatic by-products may be selectively removed from the isomerized product stream, the dehydrogenated product steam, the overhead liquid stream of the paraffin column that is recycled to the dehydrogenation section, or the selective diolefin hydrogenation product stream (if any).

In one embodiment, the process produces an MAB composition comprising phenyl- alkanes having one phenyl group and one aliphatic alkyl group, wherein the phenyl-alkanes have: (i) an average weight of the aliphatic alkyl groups of the phenyl-alkanes of between the weight of a Clo aliphatic alkyl group and a C13 aliphatic alkyl group; (ii) a content of phenyl-alkanes having the phenyl group attached to the 2-and/or 3- position of the aliphatic alkyl group of greater than 55 wt-% of the phenyl- alkanes; and

(iii) an average level of branching of the aliphatic alkyl groups of the phenyl-alkanes of from 0.25 to 1.4 alkyl group branches per phenyl-alkane molecule when the sum of the contents of 2-phenyl-alkanes and 3-phenyl-alkanes is more than 55 wt-% and less than or equal to 85 wt-% of the phenyl-alkanes, or an average level of branching of the aliphatic alkyl groups of the phenyl-alkanes of from 0.4 to 2.0 alkyl group branches per phenyl-alkane molecule when the sum of the concentrations of 2-phenyl-alkanes and the 3-phenyl-alkanes is greater than 85 wt-% of the phenyl-alkanes; and (iv) wherein the aliphatic alkyl groups of the phenyl-alkanes comprise primarily linear aliphatic alkyl groups, mono-branched aliphatic alkyl groups, or di- branched aliphatic alkyl groups, and wherein the alkyl group branches if any on the aliphatic alkyl chain of the aliphatic alkyl groups comprise primarily small substituents, such as methyl group branches, ethyl group branches, or propyl group branches, and wherein the alkyl group branches if any attach to any position on the aliphatic alkyl chain of the aliphatic alkyl groups provided that phenyl-alkanes having at least one quaternary carbon atom on the aliphatic alkyl group comprise less than 20% of the phenyl-alkanes.

One process for producing this MAB composition comprises first dehydrogenating paraffins to produce the corresponding monoolefins. The process comprises isomerizing monoolefins having an average weight between the weight of a Clo paraffin and a C13 paraffin to produce isomerized monoolefins having an average level of branching of from 0.25 to 1.4, or of from 0.4 to 2.0, alkyl group branches per olefin molecule. These isomerized monoolefins primarily comprise linear monoolefins, mono-branched monoolefins, or di-branched monoolefins, and the alkyl group branches if any on the aliphatic alkyl chain of the isomerized monoolefins primarily comprise small substituents, such as methyl group branches, ethyl group branches, or propyl group branches. The alkyl group branches of the isomerized monoolefins may be attached to any position on the aliphatic alkyl chain of the olefin, subject to certain limitations that depend on the desired characteristics of the resultant phenyl-alkanes. The isomerized monoolefins alkylate a phenyl compound to produce phenyl-alkanes. The resultant phenyl- alkanes have the characteristics that the phenyl-alkanes having the phenyl group attached to the 2-and/or 3-position of the aliphatic alkyl group comprise greater than 55 wt-% of the phenyl- alkanes, and the phenyl-alkanes having at least one quaternary carbon atom on the aliphatic alkyl group comprise less than 20% of the phenyl-alkanes.

Sulfonation of the phenyl-alkanes produced by the processes of this invention and neutralization of the sulfonated product can be accomplished by the methods described in US- A-6,187, 981.

In other aspects of the present invention, this invention is the MAB compositions and the MABS compositions produced by the processes disclosed herein. The MAB compositions produced by the processes of this invention may comprise lubricants, and the MABS compositions produced by the processes of this invention may comprise lubricant additives.

The drawing shows an arrangement for an integrated dehydrogenation-isomerization- alkylation scheme of this invention. The drawing shows a paraffinic feedstock comprising Clo- C13 normal paraffins entering the process through line 10. The paraffinic feedstock combines with a paraffinic recycle stream comprising Clo-Ci3 normal paraffins flowing in line 46 to form a combined feed stream flowing in line 12 that enters dehydrogenation section 14 for the dehydrogenation of the paraffins to olefins. Line 16 vents hydrogen from the process through.

The dehydrogenated product stream in line 18 contains C1o-Ci3 normal paraffins, Cio-Cl3 normal monoolefins, Clo-Ci3 normal diolefins, and aromatic byproducts. Selective hydrogenation section 20 receives makeup hydrogen through line 22 to selectively hydrogenates the diolefins in the dehydrogenated product stream to monoolefins thereby removing the Clo-Ci3 normal diolefins. The selective hydrogenation product stream flows through line 24 to olefin isomerization section 26 that isomerizes the normal monoolefins to lightly branched monoolefins. The isomerized product stream in line 28 contains Cln-C13 lightly branched monoolefins, Clo-Cl3 normal paraffins, and aromatic byproducts. Aromatics removal section 30 removes the aromatic byproducts and rejects them from the process via line 32. The aromatics removal section product stream flows through line 34 to the alkylation section 52 that comprises an alkylation reaction zone 36 and an alkylation separation zone 40.

Both the aromatics removal section product stream and a benzene-containing phenyl recycle stream in line 44 are charged to alkylation reaction zone 36, where the Clo-Cl3 lightly branched monoolefins allcylate benzene to produce MAB. The alkylation reaction zone effluent stream contains benzene, Clo-C13 normal paraffin, MAB, and heavy alkylbenzenes such as byproduct polyalkylbenzenes. This effluent stream flows through line 38 to the alkylation separation zone 40. A phenyl feedstock comprising benzene and flows separation zone 40 through line 42.

The alkylation separation zone 40 recovers the phenyl recycle stream flowing in line 44, the paraffinic recycle stream in line 46, heavy alkylbenzenes rejected from the process through line 50 and a product stream comprising MAB carried by line 48.

All references herein to groups of elements are to the Periodic Table of the Elements, "CRC Handbook of Chemistry and Physics,"CRC Press, Boca Raton, Florida, 80u'Edition, 1999-2000.

EXAMPLE 1 A 100 cc sample of a catalyst comprising 50 wt-% MgAPSO-31 bound with gamma alumina was placed in a reactor tube having an inside diameter of 2.22 cm (7/8 in). A feed consisting of a mixture of 1-dodecene passed over the catalyst at a liquid hourly space velocity of 5 hr 1. The catalyst temperature was initially set to 250°C (482°F) and then adjusted to maintain a desired conversion of linear olefins.

The product was analyzed by a Hewlett Packard (HP) gas chromatograph HP5890 equipped with a split/splitless injector and flame ionization detector (FID) was used. The gas chromatograph was equipped with a hydrogenator insert tube in the injector. The column was a 50-meter Hewlett Packard HP PONA column having an inside diameter of 0.2 mm. An 11 mm Restek red lite septa and an HP O-ring for the inlet liner were used. The gas chromatographic parameters included: hydrogen carrier gas; 138 kPa (g) (20 psi (g) ) column head pressure; 1 ml/min column flow; 250 ml/min split vent; 4 ml/min septum purge; 0.2 microliter injection volume; 175°C (367°F) injector temperature; 275°C (527°F) detector temperature; and an oven temperature program consisting of a hold at 50°C (122°F) for 5 min, a ramp at 3°C/min (5°F/min) to 175°C (347°F), and a ramp at 10°C/min (18°F/min) to 270°C (518°F). A sample was made ready for injection by weighing 4-5 mg of the sample into a 2 ml gas chromatograph auto sampler vial. The catalyst for the hydrogenator was prepared by preparing a solution of 20 g nickel nitrate hexahydrate and 40 ml methanol. The nickel nitrate solution was slowly poured over 20 g"Chromosorb P", which is a calcined diatomite made from crushed firebrick, in an evaporating dish. The mixture in the evaporating dish was wanned with constant stining to 65°C (149°F) on a hot plate to evaporate the methanol until the mixture appeared dry. 3g of the mixture was placed into the hydrogenator insert tube and held in position with glass wool at each end. To activate the catalyst, hydrogen carrier gas was passed at 60 ml/min through the catalyst and the temperature was raised to 350°C (662°F), and the catalyst was treated at these conditions for 3 hours. Standards required for this method are n-decane, n-undecane, n-dodecane, n-tridecane, and n-tetradecane. Relative positions of the mono methyl isomers are given in the previously mentioned article by H. Schultz et al.

The products were summed into five classifications as follows, with each classification's sum denoted as shown in brackets: light products with carbon numbers of 11 or lower [Cll-], linear olefins [linears], monomethyl branched olefins [mono], dimethyl and ethyl branched olefins [di], and heavy products with carbon numbers of Cl3 or higher [Cl3+].

Also, the following performance measures were calculated: Conversion = 100 * (1- ( [linears] product [linears] feed)) Monomethyl = 100 * ( [mono] / ( [mono] + [di])) Lights = 100 [Ci I-]/ ( [Cli-I + [linears] + [mono] + [di] + [Cl3+])) Heavies = 100 * ( [Cl3+]/ ( [Cll-] + [linears] + [mono] + [di] + [Cl3+])) The results are shown in Table 1: Table 1: Results Conversion Monomethyl Lights Heavies 69.9 86. 8 0. 64 3. 53

EXAMPLE 2 Example 1 was repeated, except that the feed consisted of a blend of Cll, Cl2, and Cl3 linear olefins. The feed contained 28.7 mol-% Cil, 39.6 mol-% Cl2, and 31.7 mol-% Cl3. The product contained monomethyl branched olefins. The distribution of monomethyl branched olefins in the product was 30.9 mol-% Cll, 42.4 mol-% Ci2, and 26.7 mol-% C13. This example shows that without recycling the distribution of the number of carbon atoms of the monomethyl branched olefin product is different from the distribution of carbon atoms of the feed.

EXAMPLE 3 A process operates as shown in the drawing except without a paraffin recycle stream flowing in line 46. A paraffinic feedstock enters the process through line 10 and MAB is recovered in line 48, and the process operates at steady state conditions. The stream flowing in line 24 has the composition of the feed in Example 2, and the stream flowing in line 28 has the composition of the product in Example 2. Then the flow of a paraffin recycle stream in line 46 is started. Once steady state conditions are reestablished, the distribution of the number of carbon atoms of the aliphatic alkyl groups of the MAB product is skewed to lower carbon

numbers than that which is obtained when the process operates without a paraffin recycle stream.

EXAMPLE 4 A process operates as shown in the drawing. A paraffinic feedstock enters the process through line 10 and MAB is recovered in line 48, and the process operates at steady state conditions. The stream flowing in line 28 has the composition shown in Table 1.

EXAMPLE 5 A starting-material of 1-dodecene was isomerized to produce an isomerized product stream comprising a blend of monomethyl C12 olefins and having the composition shown in Table 2.

Table 2: Composition of Isomerized Product Stream Olefin Component Content (wt-%) Lights'0. 64 Linear olefins2 30. 11 6-methyl undecene 7. 66 5-methyl undecene 15. 33 4-methyl undecene 11. 82 3-methyl undecene 12. 95 2-methyl undecene 8. 87 Other alk 1 olefins 9. 05 Heavies4 3. 53 Total 99. 96 1 Lights include olefins having fewer than 12 carbon atoms.

2 Linear olefins include Cl2 linear olefins.

3 Other alkyl olefins include dimethyl, trimethyl, and other C12 olefins 4 Heavies include Cl2 olefin dimers and trimers.

The isomerized product stream was mixed with benzene to produce a combined feedstock consisting of 93.3 wt-% benzene and 6.7 wt-% isomerized product stream, which corresponds to a molar ratio of benzene per olefin of 30: 1. A cylindrical reactor, which has a <BR> <BR> inside diameter of 0.875 in (22.2 mm), was loaded with 75 cc (53.0 g. ) of extrudate prepared in Example 1 of US-A-6, 111,158.

The combined feedstock was passed to the reactor and contacted the extrudate at a <BR> <BR> LHSV of 2.0 her-1, a total pressure of 500 psi (g) (3447 kPa (g) ), and a reactor inlet temperature of 125°C (257°F). At these conditions, the reactor lined out over a period of 24 hours and then a first liquid product was collected over the period of the next 6 hours.

After the period of 6 hours of collecting the first liquid product, and with the combined feedstock flowing to the reactor at a LHSV of 2.0 hf 1 and a total pressure of 500 psi (g) (3447 kPa (g) ), the reactor inlet temperature was increased from 125°C (257°F) to 150°C (302°F).

The reactor lined out over a period of 12 hours with the combined feedstock passing to the reactor and contacting the extrudate at a LHSV of 2.0 her-1, a total pressure of 500 psi (g) (3447 kPa (g) ), and a reactor inlet temperature of 150°C (302°F). At these conditions, a second liquid product was collected over the period of the next 6 hours. The results for the second liquid product are shown in Table 3.

After the period of 6 hours of collecting the second liquid product, the flow of combined feedstock to the reactor was maintained at a LHSV of 2.0 lif 1 and the total pressure was <BR> <BR> maintained at 500 psi (g) (3447 kPa (g) ). At these conditions, the reactor inlet temperature was increased from 150°C (302°F) to 175°C (347°F). The reactor lined out over a period of 12 hours with the combined feedstock passing to the reactor and contacting the extrudate at a <BR> <BR> LHSV of 2.0 ho 1, a total pressure of 500 psi (g) (3447 kPa (g) ), and a reactor inlet temperature of 175°C (347°F). At these conditions, a third liquid product was collected over the period of the next 6 hours. The third liquid product was analyzed by 13C NMR in the manner previously described. The simplified 2-phenyl-alkane selectivity and simplified internal quaternary phenyl-alkane selectivity for the third liquid product are shown in Table 3. The end quaternary phenyl-alkane selectivities are determined using the analytical and computational methods taught in US-A-6,187, 981.

Table 3: Liquid Product Analysis Simplified Simplified Internal Reactor Inlet 2-Phenyl-Alkane Quaternary Phenyl- Temperature °C (°F) Selectivity Alkane Selectivity 150 (302) 66.4 4.6 175 (347) 77. 7 2. 9

Thus, the alkylation in the example has a 2-phenyl-alkane selectivity of from 40 to 100 and a internal quaternary phenyl-alkane selectivity of less than 10. Although this example did not employ paraffin recycle, it is believed that if paraffin recycle had been used in accord with this invention, then that the 2-phenyl-alkane selectivity would have been from 40 to 100 and the internal quaternary phenyl-alkane selectivity would have been less than 10.