PROCESS TO PRODUCE FENIL-A CANOS USING ISOMERIZATION OF OLEFINS AND RECYCLING OF PARAFFIN
BACKGROUND OF THE INVENTION The present invention relates generally to the alkylation of phenyl compounds with olefins using a solid catalyst and more specifically to a process for selectively producing particular phenyl-alkanes using a solid alkylation catalyst. More than 30 years ago, many household laundry detergents were made with branched alkylbenzene sulfonates (BABS). BABS are made from a type of alkylbenzene called branched alkylbenzene (BAB). The alkylbenzenes (phenyl-alkanes) refer to a general category of compounds, which possess an aliphatic alkyl group attached to a phenyl group and having the general formula (m-alkyl) i-n-phenyl-alkane. The aliphatic alkyl group consists of an aliphatic alkyl chain to which is designated "alkane" in the formula (m? -alkyl)? -n-phenyl-alkane. Of the chains of the aliphatic alkyl group, the aliphatic alkyl chain is the longest straight chain having one carbon attached to the phenyl group. The aliphatic alkyl group may also consist of one or more branches of the alkyl group, where each is attached to the aliphatic alkyl chain and is designated by a corresponding "(mi-alkyl)?" in the formula (mi-alkylj.) i-n-phenyl-alkane. In US-A-6-187, 981 Bl the characteristics of the BABs are described. Briefly, BABs have a relatively large number of primary carbon atoms for each aliphatic alkyl group, and 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 of that one of the carbons of the aliphatic alkyl group of the BABs is a quaternary carbon. When a carbon atom in the alkyl chain is bonded to two other carbons in 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 known as "alkyl-phenyl-alkane-quaternary" or simply "quaternary". Accordingly, the quaternaries comprise alkyl phenyl alkanes having the general formula (mi-alkyl) i-n-phenyl-alkane. If the quaternary carbon is the second carbon atom from one end of the alkyl side chain, the 2-alkyl-phenyl-alkane is referred to as the "final quaternary". Any other quaternary carbon in the alkyl side chain is referred to as an "internal quaternary". 30 years ago, laundry detergents made from BABS contaminated rivers and lakes. This problem was solved with detergents made of linear alkylbenzene sulfonates (LABS), which biodegrade faster than BABS. LABS are made of alkylbenzenes called linear alkylbenzenes (LAB). US-A-6-187, 981 Bl describes LABs. LABs possess a linear aliphatic alkyl group with two primary carbon atoms, and the phenyl group in LAB is generally attached to any secondary carbon atom of the linear aliphatic alkyl group. The most recent investigations have identified certain modified alkylbenzene sulfonates, which are referred to herein as MABS. The MABS differ in composition of the alkylbenzene sulfonates BABS and LABS, and in addition to improving the operation of the cleaning in laundries and the operation of the cleaning of hard surfaces, they have an excellent efficiency in hard water, besides a biodegradability comparable to the LABS. If modified alkylbenzenes (MAM) are sulfonated, MABS are obtained. MABs are phenyl-alkanes which comprise a slightly branched aliphatic alkyl group and a phenyl group, and have the general formula (pii-alkyi) i-n-phenyl-alkane. MABs generally have two, three or four primary atoms, contain a high proportion of 2-phenyl-alkanes, and have a relatively low proportion of internal quaternaries. US-A-6-187, 981 Bl discloses a process for producing MAB by isomerization of paraffins, dehydrogenation of paraffins and alkylation with recycle of paraffins. US-A-5,276,231 discloses a process for making LAB with the selective removal of secondary aromatic products from a dehydrogenation zone of paraffins, and also reveals the recycling of paraffins to the dehydrogenation zone, the selective hydrogenation of any monoolefin in the recycle stream of paraffins, and the selective hydrogenation of diolefinic by-products from a dehydrogenation zone. For other alkylation processes and adsorptive separation processes that produce only slightly branched or de-linearized alkylbenzenes, see PCT international publications WO 99/05082, WO 99/05084,99 / 05241, WO 99/05243, and W099 / 07656 which remain incorporated. to the present by reference. Due to the advantages of MABS over other alkylbenzene sulfonates, processes and catalysts are being sought that selectively produce MAB with a desired selectivity of 2-phenyl-alkanes and internal quaternary phenyl-alkanes. SUMMARY OF THE INVENTION A process for the production of phenyl-alkanes, in particular modified alkylbenzenes (MAB), is disclosed by the steps of dehydrogenation of paraffins, isomerization of olefins and alkylation of a phenyl compound, wherein the paraffins of the effluent of Alkylation is recycled to the dehydrogenation step. The paraffins that are recycled can be linear or non-linear, including slightly branched paraffins. Since recycled paraffins can be converted to slightly branched olefins, this process efficiently recovers paraffins in the alkylation effluent, and uses them to produce valuable phenyl-alkane products. Accordingly, this process increases the production of valuable products for a given amount of paraffinic feedstock that is charged to the process, while also avoiding the difficulty of separating the paraffins from the monoolefins, after the dehydrogenation step of paraffins, and before the alkylation step. This process, when used for the alkylation of detergents, produces detergents that comply with the increasingly stringent requirements of 2-phenyl-alkane selectivity and the selectivity of internal quaternary phenyl-alkanes for the production of modified alkylbenzenes (MAB), with a greater effectiveness of cleaning in hard or cold water, and with a biodegradability comparable to the linear sulfonates of alkylbenzene. It is thought that the MABs and MABS produced by the process disclosed herein are not the products produced by the processes of the prior art, that they do not recycle paraffins, and that in the dehydrogenation zone the degree of conversion of the paraffins Branches may exceed that of normal (linear) paraffins, and that the degree of conversion of heavier paraffins may exceed that of lighter paraffins. In this case, since the equilibrium limits the degree of conversion of paraffins, the effluent from the dehydrogenation zone may contain more linear or light paraffins. Accordingly, the concentration of linear or light paraffins in the stream of recycled paraffins can be increased. This, in turn, can increase the concentration, and ultimately the conversion of linear or light paraffins in the dehydrogenation zone, until the extraction rate in the process of the linear or light paraffins by dehydrogenation and subsequent alkylation is equal to the index of introduction to the dehydrogenation zone of these paraffins, from the paraffin feed charge and the recycled paraffin stream. Accordingly, for a degree of conversion of olefins in the alkylation zone, the aliphatic alkyl chain of the MB product of the present invention will retain more carbon number similarity to the paraffinic feedstock of the prior art processes. The processes of the prior art bias the distribution of the number of carbon atoms in the aliphatic alkyl groups of the MABs to higher carbon numbers, compared to those of the present invention. After sulfonation, the MAB products of the present invention tend to retain a similar carbon number distribution of the aliphatic alkyl chain as the paraffinic feed charge. Accordingly, for a given combination of feed streams, the processes of the present invention can produce particular MAB and MABS products that possess an aliphatic alkyl chain with specially adapted branching grades, which may differ from the processes of the prior art. DETAILED DESCRIPTION OF THE INVENTION The two feedstocks that are consumed in the process of the present invention are a paraffinic compound and a phenyl compound. The paraffinic feed stream may comprise unbranched (linear) or normal paraffin molecules, which possess a total number of carbon atoms per paraffin molecule of between 8 to 28, and in other embodiments of 8 to 15, of 10 to 15 , and from 11 to 13 carbon atoms. Two carbon atoms per unbranched paraffin molecule are primary carbon atoms, and the remaining carbon atoms are secondary carbon atoms. In addition to the unbranched paraffins, other acyclic compounds can be charged to the process of the present invention. These other acyclic compounds can be charged to the process of the present invention, either to the paraffinic feedstock containing unbranched paraffins, or through one or more streams that are charged to the process of the present invention. One such acyclic compound is a slightly branched paraffin, which as used herein, refers to a paraffin having a total number of carbon atoms of between 8 to 28, of which three or four of the carbon atoms are primary carbon atoms, and none of the remaining carbon atoms with quaternaries. The slightly branched paraffin may have a total number of between 8 to 15 carbon atoms, and in another embodiment of 10 to 15 carbon atoms, and in another embodiment more between 11 to 13 carbon atoms. The slightly branched paraffin generally comprises an aliphatic alkane having the general formula (pi-alkyl) i-alkane. The slightly branched paraffin consists of the longer linear chain of the slightly branched paraffin and an aliphatic alkyl chain, which is known as "alkane" in the formula (pi-alkyl) i-alkane. The slightly branched paraffin also consists of one or more branches of the alkyl group designated by the corresponding "(pi-alkyl) i", where the subscript "i" is equal to the number of branches of the alkyl group, and where each corresponding branch of the group alkyl is attached to the carbon number pi of the aliphatic alkyl chain. The aliphatic alkyl chain is numbered from one end to the other, in a direction that assigns the smallest possible numbers to the carbon atoms possessing branches of the alkyl group. The branching or branching of the alkyl group of the slightly branched paraffin can be selected from methyl, ethyl and propyl groups, and shorter and normal branches are preferred. The slightly branched paraffins with two branches of the alkyl group or 4 primary carbon atoms may comprise less than 40 mol%, and in another embodiment less than 25 mol%, of the slightly branched paraffins. The slightly branched paraffins possessing an alkyl group branch or three primary carbon atoms may comprise more than 70 mol% of the total slightly branched monoolefins. Any branching of alkyl group can be attached to any carbon in the aliphatic alkyl chain. The process feed may include more highly branched paraffins than the slightly branched paraffins. However, in dehydrogenation, these highly branched paraffins tend to form highly branched monoolefins wherein the alkylation tends to form BAB. For example, paraffin molecules which consist of at least one quaternary carbon atom, in dehydrogenation followed by alkylation tend to form alkyl-alkanes with quaternary carbon atoms without the phenyl group. Preferably, the charge of these highly branched paraffins to the process is minimized. Paraffin molecules, on a molar basis, containing at least one carbon quaternary 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 more preferably less than 1%. The paraffinic feed charge is usually a mixture of linear and highly branched paraffins with different numbers of carbons. Any suitable method can be used to produce the paraffinic feed charge. One method produces the paraffinic feed charge by separating unbranched (linear) hydrocarbons, or slightly branched hydrocarbons from a petroleum fraction in the boiling range of kerosene. The commercial processes already demonstrated for such separation are the Molex ™ process of the
UOP, for the adsorptive separation of the liquid phase of normal paraffins from isoparaffins and cycloparaffins, and the Kerosene Isosiv ™ process of the UOP, for the adsorptive separation of the vapor phase from normal paraffins from non-normal paraffins. The feed streams to these separation processes described above comprise branched paraffins which are more highly branched than the slightly branched paraffins. Analytical methods well known in the gas chromatography technique can determine the composition of these mixtures of linear, slightly branched and branched paraffins, for the paraffinic feed charge, or the feed stream to the aforementioned adsorption separation processes. H. Schultz et al., Starting on page 315 of Chromatographia 1, 1998., which describes a suitable method of gas chromatograph with temperature programmed to identify components in complex mixtures of paraffins. For the alkylation of detergents, the phenyl compound of the phenyl feedstock comprises benzene. The phenyl compound of the phenyl feed stream can be alkylated or other higher molecular weight substituted derivatives can be obtained than benzene, including toluene, ethylbenzene, xylene, phenol, naphthalene, etc., although these alkylation products can be detergent precursors less adequate than the benzenes acquired. The process of the present invention can be divided into a dehydrogenation section, an isomerization section and an alkylation section. The present invention is not limited to a particular flow scheme for the dehydrogenation section. The dehydrogenation section can be configured essentially in the manner described in US-A-6, 187, 981 Bl. Any suitable dehydrogenation catalyst can be used. The catalyst may be a layered composition, comprising an inner core wherein the outer layer comprises an inorganic or refractory oxide having uniformly dispersed at least one metal from the platinum group (Group VIII (IUPAC 8-10)) and at least one metal promoter, and where at least one metal modifier is dispersed in the catalyst composition. The outer layer is attached to the inner core to the extent that the loss by wear is less than 10% of the weight, based on the weight of the outer layer. This catalyst composition is described in US-A-6,177,381. Dehydrogenation conditions are selected to minimize cracking and polyolefin products. Although it can occur under dehydrogenation conditions, the isomerization of olefin skeletons of the dehydrogenation section is not a requirement for the present invention, since the olefins are isomerized in the isomerization section that will be described later. Reducing the dehydrogenation temperature can minimize the isomerization of skeletons. The isomerization of skeletons under dehydrogenation conditions means an isomerization that increases the number of primary carbon atoms in a paraffin or olefin molecule. The dehydrogenated product stream containing monoolefins from the dehydrogenation section of paraffins is typically a mixture of unreacted olefins and paraffins corresponding in their backbones to the paraffins charged to the dehydrogenation section. A minimal isomerization of the paraffin skeletons and the olefins in the dehydrogenation section means that 15 mol%, and preferably less than 10 mol%, of the paraffin and olefin skeletons is isomerized. Accordingly, it is preferred that when most of the feed paraffins are linear (unbranched), most of the olefins are linear (unbranched). Linear monoolefins in the dehydrogenation reaction effluent pass to an isomerization zone of skeletons, which decreases the linearity and adjusts the number of primary carbon atoms of the olefin molecules. Isomerization of skeletons of the molecule can comprise the increase in one or two the number of branching of methyl groups of the aliphatic chain. Since the total number of carbon atoms in the olefin molecule remains the same, each additional methyl group branch causes the reduction of the aliphatic chain to a carbon number. The step of isomerization of skeletons sufficiently decreases the linearity of the dehydrogenation reaction effluent, so that after use in the alkylation of the alkylate of phenyl-alkane meets the requirements of the primary carbon atoms, selectivity of 2-phenyl-alkane , and the selectivity of internal quaternary phenyl-alkanes. The skeleton isomerization of the initial olefins can be obtained in any manner known in the art, and in any catalyst. Suitable catalysts include ferrierite, ALPO-31, SAP0-11, SAP0-31, 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, ofretite, hydrogenated forms of stilbite, magnesite or calcite forms of mordenite, and magnesite or calcite forms of partite. Suitable MeAPSO-31 catalysts include MgAPSO-31. Many natural zeolites, such as ferrierite, which have a reduced initial pore size, can be converted into suitable forms for the isomerization of olefin skeletons, by removing the alkali metal or associated alkaline earth metal by exchange of ammonium ions and calcination to produce the essentially hydrogenated form, as disclosed in US-A-4, 795, 623 and US-A-4, 924, 027. However, the H-form mordenite is not a suitable catalyst for the isomerization of skeletons of the material initial olefinic. The catalysts and conditions for skeleton 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. isomerization of skeletons include conditions in which at least a portion or all of the hydrocarbons come into contact with the skeleton isomerization catalyst in the liquid phase. The isomerization temperature is between 50 and 400 ° C. When the isomerization catalyst contains a Group VIII metal (IUPAC 8-10), the isomerization conditions include a molar ratio of hydrogen to hydrocarbon greater than 0.01: 1. The isomerized product stream for MAB production contains a slightly branched monoolefin. A slightly branched monoolefin refers to a monoolefin with a total number of carbon atoms of between 8 to 28, of which three or four of the carbon atoms are primary carbon atoms, and none of the remaining carbon atoms are atoms of quaternary carbon. The slightly branched monoolefin may have a total number of between 8 to 15 carbon atoms, preferably 10 to 15 carbon atoms, and more preferably between 11 to 13 carbon atoms. The isomerized product stream has a concentration of slightly branched monoolefins of more than 25 mol%. The slightly branched monoolefin comprises an aliphatic alkene having the general formula (pi-alkyl) i-q-alkene, and in the longer linear chain an aliphatic alkenyl containing the carbon-carbon double bond known as "alkene". The slightly branched monoolefin also consists of one or more branches of the alkyl group attached to the aliphatic alkenyl chain, and designated in the formula by a corresponding "(p-alkyla) i". The double bond is between the carbon numbers q and (q + 1) of the aliphatic alkenyl chain. The aliphatic alkenyl chain is numbered from one end, in a direction that assigns the minimum number to the carbon atoms with the double bond. The slightly branched monoolefin may be an alpha monoolefin or a vinylidene monoolefin, but preferably it is an internal monoolefin. As used herein, the term "alpha olefins" refers to olefins with the formula R-CH = CH2. The term "internal olefin", as used herein, includes di-substituted internal olefins with the formula R-CH = CH ~ R; tri-substituted internal olefins with the formula R- (R) = CH-R; and define tetra-substituted with the formula R-C (R) = C (R) -R. The di-substituted internal olefins include internal beta-defines with the formula R-CH = CH-CH3. As used herein, the term "vinylidene olefins" refers to olefins with the formula R-C (R) = CH2. In the preceding formulas, R is an alkyl group which may be identical or different from other alkyl groups in each formula. Insofar as it permitted by definition of "define internal", when the lightly branched monoolefin is an internal monoolefin, any carbon atoms in aliphatic alkenyl chain may have the double bond. The lightly branched monoolefins include octenes suitable, nonenes, decenes, undecenes, dodecenes, tridecenos, tetradecenes, pentadecenos, hexadecenes, heptadecenos, octadecenos, nonadecenos, eicosenos, heneicosenos, docosenos, tricosenos, tetracosenos, pentacosenos, hexacosenos, heptacosenos and octacosenos. Generally the branching or branching of alkyl groups of the slightly branched monoolefin are methyl, ethyl and propyl groups, where shorter and normal branches are preferred. Preferably, the slightly branched monoolefin has only one alkyl group branch, although two alkyl group branches are also possible. The lightly branched monoolefins having two branches alkyl or four primary carbon atoms may comprise less than 40 mol%, and preferably less than 30 mol%, of the total lightly branched monoolefins, where the remainder of the lightly branched monoolefins have a branch of alkyl group. The slightly branched monoolefins having one branch of an alkyl group or three primary carbon atoms may comprise less than 70 mol% of total slightly branched monoolefins. US-A-6,187,81 describes analytical methods for determining the composition of a mixture of slightly branched monoolefins. In addition to the slightly branched monoolefin, other acyclic compounds may come into contact with the alkylation catalyst. The stream of isomerized products from one or more streams can cause these other acyclic compounds to come into contact with the catalyst. Other acyclic compounds include unbranched (linear) olefins and monoolefins, including linear and non-linear paraffins. The unbranched olefins
(linear) which may come into contact with the zeolite may have a total number of carbon atoms per paraffin molecule of between 8 to 28, preferably 8 to 15, and more preferably 10 to 14 carbon atoms. The unbranched olefin can be an alpha monoolefin, although it is preferably an internal monoolefin. When present in the product stream isomerized with the slightly branched monoolefins, the content of linear olefins in the stream of an isomerized product is preferably less than or equal to 75 mol% of the total monoolefins, and more preferably less than 60 mol% of the total monoolefins. the total monoolefins. Due to the possible presence of linear monoolefins, the total isomerized product stream may contain, on average, less than 3 or between 3 and 4 primary carbon atoms per molecule of monoolefin in the isomerized product stream. Depending on the relative proportions of the linear or slightly branched monoolefins, the isomerized product stream, or the sum of all monoolefins that may come into contact with the zeolite, may have between 2.25 and 4 primary carbon atoms per molecule of monoolefin. Linear or non-linear paraffins, if any, which may come into contact with the zeolite, through the stream of isomerized products, may have a total number of carbon atoms per paraffin molecule of between 8 to 28 carbon atoms, preferably between 8 to 15 carbon atoms and more preferably between 10 to 14 carbon atoms. It is not expected that these linear and non-linear paraffins will materially interfere with the alkylation step, but rather act as a diluent. However, the presence of these diluents in the alkylation reactor generally produces higher volumetric flow rates of the process streams, which may require larger equipment and more catalysts in the alkylation reaction circuit, and larger product recovery facilities. . The isomerized product stream preferably does not contain unacceptable concentrations of impurities or contaminants that could cause difficulties in the alkylation step. There are well-known steps, such as distillation and selective hydrogenation, to convert polyolefins into monoolefins, which can remove some impurities. When monoalkylating a phenyl compound with a slightly branched olefin, the stream of isomerized product preferably contains little or none of the dimer of this slightly branched olefin in particular. Preferably, the concentration of more highly branched monoolefins than the slightly branched olefins in the isomerized product stream is minimized to prevent their conversion due to BABs in the alkylation. For example, the isomerized product stream may contain molecules of monoolefins possessing at least one quaternary carbon atom, which tends in alkylation to form phenyl-alkanes with a quaternary carbon atom that is not bound to a phenyl portion. Monoolefins having at least one quaternary carbon atom preferably comprise less than 10 mol%, and preferably less than 1 mol%, of the isomerized product stream, or the sum of all monoolefins that come into contact with the catalyst. The product of the skeleton isomerization step contains the slightly modified monoolefins, and can supply olefins to the alkylation section. Accordingly, the stream of isomerized products can be a mixture composed mainly of unreacted paraffins, linear olefins (unbranched), and branched monoolefins which typically are in the range Cs-C28, preferably in Cß-Cis, and more preferably in the range C10-C15. Between 20 to 60 mole% of the total monoolefins in the isomerized product stream are linear (unbranched) olefins. The branched monoalkyl defines in the isomerized product stream are preferably monomethyl-alkenes. The content of branched olefins in the isomerized product stream, in three embodiments of the present invention, are less than 30 mol%, between 10 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 of the product of the skeleton isomerization step. An aliquot of the product of the skeleton isomerization step is a fraction of the product of the skeleton isomerization step, which possesses essentially the same composition as the product of the skeleton isomerization step.
In addition to the isomerization of olefins, paraffin backbone isomerization can also take place in the olefin isomerization section. Any non-linear paraffin resulting in the isomerized product stream passes along with the normal (linear) paraffins through the alkylation section that will be described later, and recycled to the dehydrogenation section, where they are mixed with paraffins from the feedstock paraffinic In the dehydrogenation section, these recycled and non-linear paraffins can be dehydrogenated or not to monoolefins. These already isomerized paraffins, such as paraffins converted into olefins already isomerized, then re-enter the olefin isomerization section, where they can undergo additional isomerization. Accordingly, the stream of isomerized product contains a mixture of paraffins through the dehydrogenation, isomeration and alkylation sections. The slightly branched monoolefins in the stream of isomerized product react with a phenyl compound. The alkylation takes place in an alkylation section consisting of an alkylation reaction zone and an alkylation separation zone. The present invention can use any flow scheme from the alkylation zone. The alkylation zone can be configured essentially in the manner described in US-A-6,187,981 Bl. Any suitable alkylation catalyst can be used. The alkylation catalysts comprise zeolites with a zeolitic structure of BEA, MOR, MTW and NES. These zeolites include mordenite, ASM-4, ZSM-12, ZSM-20, offerita and melinite, beta, UN-87 and gotardiite. It is thought that the alkylation conditions produce minimal skeletal isomerization of the slightly branched monoole-fine, or any other olefin and paraffin in the isomerized product stream. A minimal skeletal isomerization means that preferably less than 15 mol%, and more preferably less than 10 mol%, of the olefin of the aliphatic alkyl chain, and any other intermediate reaction, passes through isomerization of skeletons. Accordingly, alkylation preferably occurs essentially in the absence of skeleton isomerization of the slightly branched monoolefin, and the number of primary carbon atoms in the slightly branched monoolefin is equal to the number of primary carbon atoms per phenyl-alkane molecule. Any additional methyl group branching in the aliphatic alkyl chain of the phenyl-alkane product will slightly increase the number of primary carbon atoms in the phenyl-alkane product, from the primary carbon atoms in the slightly branched monoolefin. Finally, although the formation of 1-phenyl-alkane is not significant under alkylation conditions, its production will slightly reduce the number of primary carbon atoms in the phenyl-alkane product. Alkylation of the phenyl compound with the slightly branched monoolefins yields (rrii-alkyi) i-n-phenyl-alkanes, where the aliphatic alkyl group has 2, 3 or 4 primary carbon atoms per phenyl-alkane molecule. The aliphatic alkyl group may have 3 primary carbon atoms per phenyl-alkane molecule, and preferably with methyl groups at both ends of the chain. In this embodiment, the alkylation produces monomethyl-phenyl-alkanes. However, it is not necessary that all the (mi-alkyl) i-n-phenyl-alkanes produced have the same number of primary carbon atoms per phenyl-alkane molecule. Between 0 to 75 mol%, and preferably 0 to 40 mol%, of the (mi-alkyl) i-n-phenyl-alkanes produced may have 2 primary carbon atoms per phenyl-alkane molecule. As many as possible, and preferably from 25 to 100 mole% of the produced (mi-alkyl) i-n-phenyl-alkanes, can have 3 primary carbon atoms per phenyl-alkane molecule. In one embodiment, from 0 to 40 mol% of the (mi-alkyl) i-n-phenyl-alkanes produced can have 4 primary carbon atoms; accordingly, (m-methyl) -n-phenyl-alkanes with a single methyl group branching are preferred, and are designated herein as monomethyl-phenyl-alkanes. The number of primary, secondary and tertiary carbon atoms per molecule of phenyl-alkane product can be determined by editing the high-resolution nuclear magnetic resonance (NMR) spectrum of multiple pulses, and by increasing without distortion of polarization transfer (DEPT), as described in the brochure entitled "High Resolution Multipulse NMR Spectrum Editing and DEPT", distributed by Bruker Instruments, Inc., Manning Park, Billerica, Massachusetts, USA. The selectivity parameters for alkylation to 2-phenyl-alkanes and quaternary phenyl-alkanes were determined in the prior art, using two slightly different analytical and calculation methods. US-A-6,111,158 and US-A-6,187,981 use methods that result in different selectivities. The selectivities determined by the methods of US-A-6, 111,158 are designated herein as simplified selectivities, and the 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 slightly branched monoolefins has a selectivity of 2-phenyl-alkanes of between 40 and 100, and preferably from 60 to 100 in another embodiment, and an internal quaternary phenyl-alkane selectivity of less than 10 in one embodiment, preferably less than 5. Quaternary phenyl-alkanes can be formed by alkylating the phenyl compound with a slightly 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 phenyl-quaternary alkane may be in an internal or end quaternary. At least a portion of the excess liquid stream from the paraffin column in the alkylation separation zone is recycled to the dehydrogenation section. The recycled portion of the excess liquid stream may be an aliquot portion of the excess liquid stream. The process can selectively hydrogenate any diolefin present in the dehydrogenated product stream. Part of the excess liquid stream from the paraffin column can be recycled to the isomerization section, since the excess liquid stream from the paraffin column may contain monoolefins. However, the concentration of monoolefins in the excess liquid stream of the paraffin column is generally less than 3% by weight. The process can selectively remove any aromatic by-product present in the dehydrogenated product stream. The aromatic by-products can be selectively removed from the isomerized product stream, from the dehydrogenated product stream, from the excess liquid stream from the paraffin column that is recycled to the dehydrogenation section, or from the product stream of selective hydrogenation of diolefin (if any). The present process produces a MAB composition comprising phenyl-alkanes with a phenyl group and an aliphatic alkyl group, wherein the phenyl-alkanes possess: (i) An average weight of the aliphatic alkyl groups of the phenyl-alkanes between the weight of a C10 aliphatic alkyl group and a C13 aliphatic alkyl group. (ii) A content of phenyl-alkanes possessing the phenyl group attached to the 2 or 3 position of the aliphatic alkyl group of more than 55% by weight of the phenyl-alkanes. (iií) An average level of branching of the aliphatic alkyl groups of the phenyl-alkanes of between 0.25 to 1.4 branches of the alkyl group per molecule of phenyl-alkanes, when the sum of the content of the 2-phenyl-alkanes and 3- Phenyl-alkanes is more than 55% by weight, and less than or equal to 85% of the weight of the phenyl-alkanes, at an average branching level of the aliphatic alkyl groups of the phenyl-alkanes of from 0.4 to 2.0 branches of the alkyl group per phenyl-alkane molecule, when the sum of the concentration of 2-phenyl-alkanes and 3-phenyl-alkanes is more than 85% by weight of the phenyl-alkanes. (iv) Where the aliphatic alkyl groups of the phenyl-alkanes comprise mainly linear aliphatic alkyl groups, mono-branched aliphatic alkyl groups or di-branched aliphatic alkyl groups and where the branching of the alkyl groups, if any, in the aliphatic alkyl chain of the aliphatic alkyl groups, they comprise mainly short substituents, such as branching of the methyl group, branching of the ethyl group or branching of the propyl group, and where the branching of the alkyl group, if any, are attached to any position in the aliphatic alkyl chain of the aliphatic alkyl groups, provided that the phenyl-alkanes have at least one quaternary carbon atom in the aliphatic alkyl group comprising less than 20% of the phenyl-alkanes. A 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 C10 paraffin and a C13 paraffin, to produce isomerized monoolefins with an average branching level of between 0.25 and 1.4, or between 0.4 to 2.0 branches of the alkyl group by olefin molecule. These isomerized monoolefins comprise mainly linear monoolefins, mono-branched monoolefins or di-branched monoolefins, and the branching of the alkyl group, if any, in the aliphatic alkyl chain of the isomerized monoolefins comprises mainly short substituents such as branched methyl group branches, ethyl group or ramifications of the propyl group. The branches of the alkyl group of the isomerized monoolefins can be attached at any position on the aliphatic alkyl chain of the olefin, subject to certain limitations depending on the characteristics of the resulting phenyl-alkanes. The isomerized monoolefins alkylate a phenyl compound to produce denyl-alkanes. The resulting phenyl-alkanes have the characteristic that the phenyl-alkanes having the phenyl group attached to the 2 or 3 position of the aliphatic alkyl group comprise more than 55% of the phenyl-alkanes, and the phenyl-alkanes they have when minus one quaternary carbon atom in the aliphatic alkyl group comprise less than 20% of the phenyl-alkanes. The sulfonation of the phenyl-alkanes produced by the processes of the present invention, and the neutralization of sulfonated product, can be obtained by methods described in US-A-6,187,981.
In other aspects of the present invention, the present invention are MAB compositions and MABS compositions produced by the processes disclosed herein. The MAB compositions produced by the processes of the present invention may comprise lubricants, and the MABS compositions produced by the processes of the present invention may comprise lubricant additives. The figure shows an arrangement for a dehydrogenation-isomerization-alkylation scheme of the present invention. The figure shows a paraffinic feedstock comprising normal C? 0-C3 paraffins entering the process via line 10. The paraffinic feedstock is combined with a paraffin recycle stream, comprising normal flowing C10-C13 paraffins by line 46 to form a combined feed charge flowing through line 12 and entering dehydrogenation section 14, to dehydrogenate the paraffins into olefins. Line 16 purges hydrogen from the process. The dehydrogenated product stream in line 18 contains normal C10-C13 paraffins, C10-C13 normal monoolefins, C10-C13 normal diolefins and aromatic side products. The selective hydrogenation section 20 receives hydrogen of composition by line 22 to selectively hydrogenate the diolefins in the dehydrogenated product stream to monoolefins, whereby normal C10-C13 diolefins are removed. The selective product hydrogenation stream flows through line 24 to the olefin 26 isomerization section which isomerizes the normal monoolefins into slightly branched monoolefins. The isomerized product stream in line 28 contains slightly branched C? O-Cx3 monoolefins, C0-CX3 normal paraffins and aromatic by-products. The aromatics removal section 30 removes the aromatic by-products and rejects them from the process via line 32. The product stream from the aromatics removal section flows via line 34 to the alkylation section 52, which contains an area of alkylation reaction 36 and an alkylation separation zone 40. Both the aromatics removal section product stream and the benzene-containing phenyl recycling stream in line 44 are charged to the alkylation reaction zone 36, where the slightly branched monoolefins Cx0-Cx3 alkylate benzene to produce MAB. The effluent stream from the alkylation reaction zone contains benzene, normal paraffin Cx0-C13, MAB and heavy alkylbenzenes, co or polyalkylbenzenes by-products. This effluent stream flows via line 38 to the alkylation separation zone 40. A phenyl feedstock comprising benzene flows to the separation zone 40 via line 42. The alkylation separation zone 40 recovers the recycle stream of phenyl flowing on line 44, the paraffinic recycle stream on line 46, the heavy alkylbenzenes rejected from the process by line 50, and a stream of products containing MAB carried along line 48. All references herein Groups of elements are based on the Periodic Table of Elements, "CRC Handbook of Chemistry and Physics," CRC Press, Boca Raton, Florida, USA, 80th Edition, 1999-2000. EXAMPLES Example 1 A sample 100 of a catalyst comprising 50% by weight of MgAPSO-31 bound with gamma alumina was placed in a reactor tube with an inside diameter of 2.22 cm. A feed of a mixture of 1-dodecene at an hourly liquid space velocity of 5 hr was passed over the catalyst. The catalyst temperature was initially set at 200 ° C, and then adjusted to maintain a desired conversion of linear olefins. The product was analyzed by a Hewlett Packard (HP) HP5890 gas chromatograph equipped with an injector with or without division, and a flame ionization detector (FID) was used. The gas chromatograph was equipped with a hydrogenator insertion tube in the injector. The column was a Hewlett Packar (HP) PONA column of 50 meters and an internal diameter of 0.2 mm. A light red 11 mm Restek tube and an HP ring for the entry line were used. Gas chromatography parameters included: hydrogen transport gas; column head pressure 138 kPa (g); column flow of 1 ml / min; division purge of 250 ml / min; purge of 4 ml / min; 0.2 microliter injection volume; injector temperature of 175 ° C; detector temperature of 275 ° C; and a furnace temperature program that consisted of a lapse of 50 ° C for 5 minutes, a ramp of 3 ° C / min until reaching 175 ° C, and a ramp at 10 ° C / min until reaching 270 ° C. A sample for injection was finished by weighing 4 to 5 mg of the sample in a 2 ml auto-sampler flask for the gas chromatograph. The catalyst for the hydrogenator was prepared by preparing a solution of 20 g of nickel nitrate hexahydrate and 40 ml of methanol. The nickel nitrate solution was slowly poured onto 20 g of "Cromosorb P", which is a calcined diatomite made of ground refractory brick, in an evaporation dish. The mixture was heated on the evaporation plate with constant stirring at 65 ° C on a hot plate, to evaporate the methanol until the mixture became dry. 3 g of the mixture was placed in the hydrogenator insertion tube, and kept in place with glass wool at each end. To activate the catalyst, hydrogen transport gas was put at 60 ml / min by the catalyst, and the temperature was raised to 350 ° C, and the catalyst was treated at these conditions for 3 hours. The standards required for this method are n-decane, n-undecane, n-dodecane, n-tridecane and n-tetradecane. The relative positions of the monomethyl isomers appear in the aforementioned article by H. Schultz et al. The products were added into five classifications as follows, where each classification sum is denoted as shown in parentheses: light products with carbon numbers of 11 or less [Cu-], linear [linear] olefins, branched monomethyl olefins [mono], branched dimethyl and ethyl olefins [di], and heavy products with carbon numbers of C13 or more [C3.3 +]. In addition, the following operating measures were calculated: Conversion = 100 * ([linear] pipeline / [linear] power)) Monomethyl = 100 * ([mono] / ([mono] + [di])) Lightweight = 100 * ([Cu-] / ([Cu] + [linear] + [mono] + [di] + [C13 +])) The results are shown in Table 1 Table 1 Results
Example 2 Example 1 was repeated, except that the feed consisted of a mixture of linear olefins Cu, C12 and C13. The mixture contained 28.7 mole% Cu, 39.6 mole% C12 and 31.7 mole% C3. The product contained branched monomethyl olefins. The distribution of branched monomethyl olefins in the product was 30.9 mole% Cu, 42.4 mole% Ci2 and 26.7 mole% Cx3. This example demonstrates that without recycling, the distribution of the number of carbon atoms of the branched monomethyl olefin product is different from the distribution of carbon atoms in the feed. Example 3 A process operates as shown in the figure, except that a recycle stream of paraffins does not flow through line 46. A paraffinic feed load enters the process via line 10, and MAB is recovered on line 48, and the process operates at steady state conditions. The stream flowing on line 24 has the composition of the feed in Example 2, and the stream flowing on line 28 has the product composition in Example 2. Then the flow of a paraffin recycle stream is started. on line 46. Once the steady-state conditions are restored, the carbon number distribution of the aliphatic alkyl groups of the MAB products is skewed to smaller numbers of carbons than would be obtained when the process operates without a paraffin recycling stream.
Example 4 A process operates as shown in the drawing. A paraffinic feed load enters the process via line 10 and MAB is recovered on line 48, and the process operates at steady state conditions. The stream flowing through line 28 has the composition shown in Table 1. Example 5 An initial material of 1-dodecene is isomerized to produce an isomerized product stream comprising a mixture of monomethyl C 2 olefins and they have the composition shown in Table 2. Table 2 Composition of the isomerized product stream
"" The light ones include olefins with less than 12 carbon atoms, and linear olefins include linear olefins.
Cl 2 Alkyl olefins include dimethyl, trimethyl and other C 2 olefins. 4 Heavies include dimers and trimers of C12 olefins. The stream of isomerized product was mixed with benzene to produce a combined feedstock consisting of 93.3% by weight of benzene and 6.7% by weight of isomerized product stream, which corresponds to a molar ratio of benzene to olefin of 30: 1. A cylindrical reactor with an inside diameter of (22.2 mm) was charged with 75 cc (53 g) of extrudate prepared in Example 1 of US-A-6,111,158. The combined feedstock was passed to the reactor and the extrudate was contacted at a VELH of 2.0hr_1, a total pressure of 3,447 kPa (g), and a reactor inlet temperature of 125 ° C. Under these conditions the reactor was activated for a period of 24 hours, and then a first liquid product was collected during the period of the following 6 hours. After a period of 6 hours of collecting the first liquid product, and with the combined feed charge flowing to the reactor to a VELH of 2. Ohr-1 and a total pressure of 3,447 kPa (g), the inlet temperature was increased of the reactor from 125 to 150 ° C. The reactor was activated for a period of 12 hours, with the combined feed charge flowing into the reactor and coming into contact with the extrudate at a VHEL of 2.0hr ~ 1, a total pressure of 3,447 kPa (g), and a temperature reactor input of 150 ° C. To these conditions a second liquid product was collected during the lapse of the following 6 hours. The results of the second liquid product are shown in Table 3. After the lapse of 6 hours of collecting the second liquid product, the combined feed charge flow to the reactor was maintained at a VELH of 2.0hr_1, and the total pressure was maintained at 3,447 kPa (g). Under these conditions, the reactor inlet temperature was increased from 150 to 175 ° C. The reactor was activated for a period of 12 hours, with the combined feed charge passing to the reactor and coming into contact with the extrudate at a VHEL of 2.0hr-1, a total pressure of 3,447 kPa (g) and an inlet temperature of reactor of 175 ° C. To these conditions, a third liquid product was collected during the period of the following 6 hours. The third liquid product was analyzed by 13 CNMR in the manner previously described. The simplified selectivity of phenyl-alkane and the simplified internal quaternary phenyl-alkane selectivity for the third liquid product are shown in the table. The selectivities of extreme quaternary phenyl-alkanes were determined using analytical and calculation methods disclosed in US-A-6, 187, 981.
Table 3 Analysis of Liquid Products
Accordingly, the alkylation in the Example has a selectivity of 2-phenyl-alkanes of between 40 to 100, and a selectivity of internal quaternary phenyl-alkanes of less than 10. Although this example did not use recycled paraffins, it is thought that if the paraffin recycling according to the present invention would have been used, then the selectivity of 2-phenyl-alkanes would have been between 40 and 100, and the selectivity of internal quaternary phenyl-alkanes would have been less than 10.