WO2000018707A1

WO2000018707A1 - ALKYLATION OF AROMATIC COMPOUNDS WITH α-OLEFINS USING ZEOLITE CATALYSTS

Info

Publication number: WO2000018707A1
Application number: PCT/US1999/022412
Authority: WO
Inventors: William Dennis Mcghee; Erik Delisle Sall; Robert Gene Smith, Jr.
Original assignee: Solutia Inc.
Priority date: 1998-10-01
Filing date: 1999-09-27
Publication date: 2000-04-06
Also published as: AU6165399A

Abstract

The present invention is a process for the preparation of a monoalkylated aromatic compound. This process includes the steps of combining a zeolite catalyst in the amount of about 0.5 weight % to about 3 weight % based on total reactants, together with an aromatic compound in a batch reaction chamber. The combined zeolite and aromatic compound are then heated to a reaction temperature. An alpha olefin is then added to the reaction chamber as an alkylating agent by metered addition, so that the olefin is consumed by chemical reaction with the aromatic compound essentially simultaneously with its addition, and the concentration of olefin in the reaction mixture is maintained to as close to zero as possible. The molar ratio of initially charged aromatic compound to the total amount of alpha olefin employed in the reaction ranges from 1:1 to 10:1.

Description

ALKYLATION OF AROMATIC COMPOUNDS WITH Cϋ-OLEFINS USING ZEOLITE CATALYSTS

Description

The present invention is related to the alkylation of aromatic compounds. More particularly, the invention describes the mono-alkylation of aromatic compounds by controlling the rate of addition of the alkylating agent.

Technical Field

The alkylation of aromatic compounds such as benzene, naphthalene, anthracene, biphenyl , diphenyl oxide, etc., with long chain aliphatic compounds has been the subject of numerous articles and patents. These alkylated materials have been cited as useful as heat transfer fluids and lubricants .

The alkylation of aromatics with long chain olefins, in particular α-olefins, or with long chain alcohols, or long chain alkyl halides using acidic catalytic materials has been the subject of several investigations. Lewis acidic homogeneous systems have in the past dominated the literature as catalysts for this reaction. The use of AlX₃, BX₃, HX (in particular HF) are examples of catalyst which give high rates of alkylation, but with low selectivity.

In the alkylation of aromatics with long chain hydrocarbons, selectivity differences can arise in three different modes 1) chain position 2) aromatic position and 3) mono, di, tri etc. alkylation on the aromatic ring.

For each positional isomer described above a second, third, etc. alkylation can take place competitively with mono-alkylation giving di, tri, etc. alkylated products.

Added complications also arise because the purity of α-olefins in general, is not 100%. Typically, for example, the 1-hexadecene contains non-linear C₁₆ olefins (i.e., some branched olefins) as well as a small percentage of saturated hexadecane .

The alkylation of polyaromatic systems such as naphthalene, diphenyl ether and biphenyl has been the subject of several investigations. The use of zeolites, and in particular the use of Zeolite Y and it's ultrastable version (USY) has been employed with the most success.

Background Art

In PCT WO 95/17361 a method is described for the alkylation of naphthalene with C₁₂-C₂₀ olefins using USY zeolites containing rare earth cations. These catalysts produced primarily mono-alkylated naphthalenes. The alkylation reaction described was carried out at a 1:1.2 molar ratio of naphthalene to 1-hexadecene with 5% by weight catalyst at 200°C for 4 hr. In all cases described the reaction between olefin and aromatic took place in the batch mode. Optimal conditions/catalyst gave a final product mixture containing 2.5 weight % unreacted naphthalene, 13.6 weight % hexadecene (isomer not disclosed), 82.1 weight % monoalkylated naphthalene and 1.8 weight % dialkylated naphthalene (distribution of alkylated isomers not disclosed) . -

In U.S. 5,191,134 the use of ultra-large pore zeolites, MCM-41 was shown to give high conversions of naphthalene (90%) and cϋ-olefin (99%) using 2.85 weight % catalyst at 400°F for 6 hours at a 2:1 olefin to naphthalene ratio giving 28% mono-alkylated product, 44% di-alkylated product and 18% higher alkylates.

In U.S. 5,191,135 the addition of water at low levels (1-3 weight %) to reaction mixtures containing a 2:1 of-olefin to naphthalene ratio with 5 weight % USY zeolite at 400°F for 6 hours was shown to give higher selectivities toward mono-alkylation than without the addition of water.

PCT WO 95/18083 discloses that higher selectivities toward the mono-alkylation of naphthalene can be achieved by the use of USY zeolite catalysts by the incorporation of both protons and ammonium ions into exchange sites. Alkylation conditions were typically 5 weight % catalyst at a 1:1.2 molar ratio of naphthalene to olefin at 200°C for 4 hours.

In all of the above-mentioned cases the reaction was carried out in a batch mode with no attempt made to minimize the concentration of either reactant with the catalyst.

The use of zeolites as catalysts in the alkylation of diphenyl oxide (DPO) using α-olefins was reported in 1983.

Conditions cited were 1:1 ratio of DPO to olefin at 190-220°C for 5-6 hours giving predominately mono-alkylated products. Specific zeolites were not disclosed, nor were yields or absolute selectivities given. See Y.E. Anpilogov, et al . ,- "Kinetics and Mechanism of Alkylation of Diphenyl Ether and its Homologs", (Eff. Soversh Tekhnol . Proizvod. Monomerov. Rastvoritelei Baze Olefinovogo Syr'ya, 1983, 76-81).

In U.S. 5,552,071 a process is described for the conversion of diphenyl ether to alkylated diphenyl ether using USY catalysts at 4 weight % at 200°C for 6 hours. Within the body of the patent the conversion and yields of reaction were not given making it difficult to ascertain from this work the selectivity of the alkylation reaction. Mentioned in this patent is the use of alkylated DPO as a lubricant in high temperature applications.

In the absence of aromatic compounds, α-olefins will oligomerize using strong acid catalysts such as zeolites. In Studies in Surface Science and Catalysis, vol. 84, pp. 1701- 1704 (1994), various acid catalysts, including several USY materials, were studied in the oligomerization of C₁₂-C₁₈ olefins at 140-300°C. Standard conditions were 10 weight % catalyst, 180°C for 4 hours with C₁₄ olefin. Conclusions from this work indicate that a substantial amount of olefin dimerization/trimerization takes place using USY zeolites.

U.S. 5,132,477 describes the oligomerization of 1-olefins to poly-α-olefins and then alkylation of such to aromatic systems using acid catalysts. The oligomerized olefins are in the C₃₀-C₃₀₀₀ range. In U.S. 5,302,732 a process is described for the alkylation of benzene using c-olefins (C₆-C₂₀) using a silica-alumina catalyst with the ratio of silica to alumina 1:1 to 19:1 with less than 0.1 weight % sodium present . The alkylation reaction gives >98% olefin conversion with >85% selectivity toward mono- alkylation.

In all of the above examples the use of zeolites, and in particular USY zeolites were used to alkylate aromatics with the focus on mono-alkylation. Zeolite modifications were made to optimize this selectivity toward mono-alkylation; however, little effort went into the optimization of reaction conditions with the goal of minimizing the reactions which deactivated the catalyst.

U.S. 5,073,653 discloses a continuous reaction process for the alkylation of aromatic substrates with a C₂ to C₄ alkylating agent. This liquid phase alkylation process is carried out using a plurality of series connected reaction stages operating at an average temperature not exceeding 300° C with the interstage injection of the C₂ to C₄ alkylating agent in a manner to maintain at least 1 mole percent of alkylating agent solubilized in the aromatic substrate. Preferably at least 2 mole percent alkylating agent is solubilized. These conditions are said to provide high conversion efficiency and high selectivity to monoalkylation.

U.S. 3,251,897 discusses alkylation of aromatic compounds in the presence of a zeolite catalyst. The preferred alkylating agents are C₁ to C₂₀ olefins. In accordance with this process, it was found that polymerization and side reactions of the alkylating agent could be reduced by regulating the order of addition of the reactants into the reactor. More specifically, the compound to be alkylated can be charged- into the reactor first and allowed to substantially saturate the catalyst before adding the alkylating agent. In vapor phase processes the aromatic/alkylating agent ratio was found to have a significant impact on the rate of deactivation of the catalyst. The higher the ratio, the lower the rate of deactivation. For example, it was found that in the vapor phase that at a benzene to ethylene ratio of 12:1, the rate of deactivation of the catalyst is approximately 1/4 less than when the benzene to ethylene ratio is 3:1. These affects of the ratios on deactivation of the catalyst were less pronounced in liquid phase reactions. There it was found that ratios of benzene to ethylene of 7.7:1 resulted in the reaction proceeding for 79 hours. Even at ratios of benzene to ethylene of 4.3:1, the reaction was able to proceed for 71 hours. Thus, extremely high benzene to ethylene ratios were not as advantageous in the liquid phase.

U.S. 3,641,177 discusses a process for alkylating aromatic compounds in the presence of a zeolite. C₂ to C₄ alkylating agents are preferred. The alkylating agent is added in the gas phase and the molar ratios of aromatics : olefins range from 1:1 to about 15:1. This patent contains no data on yields or amounts of reactants converted.

U.S. 5,019,669 is another process for alkylating aromatic compounds employing zeolite catalysts. The '669 patent, however, uses a Reactive Distillation™ reactor. Solid particulate catalyst is slurried in the aromatic feed stream and fed to a reaction zone containing inert distillation packing. C₂ to C₂₀ olefin is vaporized and fed to the bottom of the reaction zone. The greater the excess of organic - aromatic compound the more the selectivity to the monosubstituted product is improved. U.S. 5,243,115 makes a similar disclosure, but cautions that too high a level of aromatic compound requires a high reflux ratio and results in a low unit productivity.

Improvements in the technology of the process of the mono- alkylation of aromatic compounds is needed to make better use of the catalytic ability of the zeolite. Not only are zeolites expensive, disposing of spent zeolite can also be expensive. It is therefore, highly desirable from an economic and practical standpoint to minimize the use of catalyst without sacrificing the selectivity of the reaction or activity.

It is known in the literature that zeolites deactivate in the presence of high concentrations of olefin. It has not been shown however, that benefit can be gained by minimizing the relative concentration of olefin in reaction mixtures in the alkylation of aromatic compounds.

It has been pointed out that kinetically, the reaction of DPO with hexadecene is a second order reaction. This implies that the concentration of both reactants contribute to the overall rate of reaction. One would suspect that greater rates of product formation would result by keeping the concentration of both reactants high during the course of reaction. Accordingly, the minimization of either reagent should severely effect the time to complete the alkylation reaction.

It is therefore an object of the present invention to provide a process which improves the selectivity of the reaction to produce primarily monoalkylated product.

It is also an object of the invention to prolong the life of the catalyst during the reaction in order to improve the economics of the process by extending the utility of the catalyst so that greater conversions to product are possible.

It is also an object of the invention to permit the use of lower amounts of zeolite catalyst than employed in prior processes .

These objectives, and others which will be apparent to one of ordinary skill in the art, can be achieved by keeping the olefin concentration in the reactor as low as possible, for example by controlled addition of the olefin to the reactor over the course of the reaction, or less preferably, by delaying addition of all the olefin until the reactor has been brought to reaction temperature.

Disclosure of Invention

We have found that by careful control of olefin concentration in the reaction mixture that high selectivities of mono-alkylation can be maintained at short reaction times with a substantial decrease in catalyst use. To obtain the greatest conversions at low catalyst levels the concentration of olefin should be kept as close to zero as possible. This low concentration of olefin is achieved by- adding the olefin to the reaction mixture at a rate which matches or nearly matches, the rate of olefin consumption, i.e., the olefin is consumed by reaction with aromatic compound nearly essentially simultaneously with the addition of the olefin. As used herein, this addition of olefin is referred to as "controlled addition" or "metered addition" .

Brief Description of Drawings

Figure 1 is a graph showing the percent of monoalkylated diphenyl oxide produced as a function of time using a bulk addition of alpha olefin and a metered addition of alpha olefin with a USY zeolite BB10.

Figure 2 is a graph showing the percent of monoalkylated diphenyl oxide produced as a function of time using a bulk addition of alpha olefin and a metered addition of alpha olefin with a calcined USY zeolite, 500 PN.

Figure 3 is a graph showing the percent of monoalkylated diphenyl oxide produced as a function of time using a bulk addition of alpha olefin and a metered addition of alpha olefin with a fully protonated USY zeolite, DD-12.

Figure 4 is a graph showing the percent of monoalkylated biphenyl produced as a function of time using a bulk addition of alpha olefin and a metered addition of alpha olefin with a selectively calcined USY zeolite, 500 PN.

Figure 5 is a graph showing the percent of alkylated naphthalene produced as a function of time using bulk addition of alpha olefin and a metered addition of alpha olefin with selectively calcined USY zeolite 500 PN.

Best Mode of Carrying Out the Invention

The present invention is a process for the preparation of a monoalkylated aromatic compound. This process includes the steps of combining a zeolite catalyst and an aromatic compound in a reaction chamber. The combined zeolite and aromatic compound are then heated to a reaction temperature. An alpha olefin is then added to the reaction chamber as an alkylating agent. The alpha olefin is added by metered addition, so that the olefin is consumed by chemical reaction with the aromatic compound essentially simultaneously with its addition and the concentration of olefin in the reaction mixture is maintained to as close to zero as possible. The molar ratio of initially charged aromatic compound to the total amount of alpha olefin employed in the reaction ranges from 1:1 to 10:1.

The reaction of the present invention is carried out in the liquid phase using conventional batch processing equipment, known to those of ordinary skill in the art . Any inert atmosphere, such as nitrogen, may be used to exclude oxygen. Atmospheric pressure is suitable for most reactions, although a positive pressure can be used if necessary to keep the reactants in the liquid phase.

Zeolite catalysts of several types are useful in the present invention. For example Zeolite Y is useful, as well as Mordenites. Ultrastable Y (USY) zeolite of several types has proven useful. Those that are either fully or partially protonated, or exchanged with sodium or ammonium or other ions are useful in the present invention. Powdered or bound forms of zeolites are also useful . Most preferred in the present invention are USY zeolites.

Zeolite is used in the reaction in an amount ranging from about 0.5 to about 3.0 weight percent (based on the total weight of the aromatic compound and the total weight of the alpha olefin) . Using about 0.75 to 1.5 weight % is preferred, with about 0.9 to 1.1 weight percent being most preferred.

The compounds to be alkylated in the present invention are aromatic compounds including both mono-aromatics, such as benzene, and poly-aromatics . More preferably, they are polyaromatic, such as biphenyl (BP) , naphthalene (NP) , diphenyl ether or diphenyl oxide (DPO) , anthracene and the like. Most preferred is DPO.

The molar ratio of the total amount of aromatic compound to the total amount of alpha olefin added to the reaction can range from about 1:1 to about 10:1, with about 5:1 to about

1.5:1 being the preferred range. The most preferred ratio is about 2.5:1 to 1.75:1, aromatic to olefin. C₈ olefins up to oligimerized ethylene may be used as the alkylating agents in the present invention. More preferred are C₈-C₂₀ alpha-olefins, with C₁₂-C₁₈ alpha olefins being meet preferred.

Reaction conditions for the alkylation process include a reaction temperature in the range of from about 175°C to 250°C, with a temperature of 180°-230°C being preferred.

Since the reaction in accordance with the present invention proceeds so as to consume the olefin essentially as soon as it is added, the reaction necessarily proceeds at a very large excess of aromatic compound to olefin.

As can be seen from the following examples, the process of the present invention is highly selective for the production of the desired monoalkylated aromatic compounds. The amounts of dialkylated compounds relative to the monoalkylated compounds is very small. Additionally, the desired monoalkylated compounds are produced in high yield.

The invention is further described by the following examples. Variations in conditions will be apparent to one of ordinary skill in the art. EXAMPLES

Experimental Materials ^~

Zeolites used were supplied by Zeolyst International (PQ Corporation) and used as powders for this study. 1-Hexadecene was supplied for example, from Chevron Chemical Company under the tradename "Gulftene 16" or Shell Oil Company, under the tradename "Neodene (R) 16 alpha olefin", and was typically >92% 1-hexadecene with the balance as a mixture of hexadecane and other olefinic compounds. Diphenyl oxide was supplied either by Solutia, Inc. or Aldrich.

Naphthalene and biphenyl were supplied by Aldrich and used as received.

Detection Methods

Normal Phase HPLC Method:

Column - Zorbax Rx silica, 4.6 x 250 mm

Mobile Phase - 0.2% isopropyl alcohol in hexane, isocratic

Flow Rate - 1.0 ml/min.

Injection volume - 20 uL

Detection -- 270nm, UN Run Time - approx. 6 min.

Sample prep.: 1.5 uL in 1.65 ml. hexanes

Analysis for diphenyl oxide, monohexadecylDPO and dihexadecylDPO was by area percent. Analysis for biphenyl, monohexadecylBP, and dihexadecylBP was by area percent and were based on calibration of biphenyl vs. alkylated biphenyls. Analysis for naphthalene, monohexadecylNP and dihexadecylNP was by area percent and were based on calibration of naphthalene vs. alkylated naphthalenes.

Hexadecene was not detected at 270 nm.

The analysis for the fingerprint of monohexadecylarene isomer distribution was made by G.C. GC Method:

Column - DB-1, 60m x 0.45mm (ID) film thickness of 1.2u Carrier flow - 10 ml/min. He Total Flow - -300 ml/min. Detector - FID at 350°C Injector - Direct injection, temp. 325°C Sample size - 1.0 uL, direct injection Column gradient 170°C to 210°C at 4 C/min. to 285°C at 15°C/min. (hold for 14 min.) to 325°C at 50°C/min (hold for 10 min.;

Sample prep. : 35uL in 1.25 ml. chloroform Integrator - ChromJet w/basic File Spec. - Inhibit integration for first 4.25 min. Chart speed at 0.5 in/min. first 8 min., then at 0.1 in/min. next 10 min. , (from 18 min - 28 min.) . Return chart to 0.1 in/min. for balance of run.

Run time 39.1 min. Composition of Zeolites as received:

Calcination of Ammonium USY:

Under a flow of nitrogen, 20 g of 500PN (USY zeolite from Zeolyst International) was heated to 400°C for 5 hrs .

EXAMPLE 1 Batch Reaction

Batch reactions of aromatic compounds with 1-hexadecene were conducted as in the following example:

A three neck Morton flask was fitted with an overhead mechanical stirrer, a nitrogen inlet (static nitrogen at atmospheric pressure) , an addition funnel for the introduction of olefin and a thermocouple to monitor internal temperatures. Catalyst in the amount of about 1 weight percent was charged into the flask and a nitrogen atmosphere swept over the system while heating to 100-105°C. To the preheated catalyst was added 0.4 mole aromatic compound and the mixture was further heated to reaction temperature. To the aromatic compound and catalyst at reaction temperature 0.2 mol 1-hexadecene was added all at once. The reaction mixture was sampled periodically and analyzed by HPLC and by GC. EXAMPLE 2

Metered reaction of 1-hexadecene with Diphenyl Oxide

A 500 mL Morton flask was fitted with an overhead mechanical stirrer, a nitrogen inlet (static nitrogen atmosphere) , a thermocouple for internal temperature measurement and an inlet for 1-hexadecene introduction. The flask was charged with 2.66 g 500PN catalyst (approximately 1 weight percent of the total of the amount of DPO and the total amount of 1- hexadecene) which had been calcined at 400 °C for 5 hr. Under a nitrogen atmosphere the catalyst was heated to 100-105°C to which was added 154.2 g (0.9 mol) diphenyl ether and this was further heated to 205°C. Under nitrogen and at 205°C, 110.3 g (at 92%, 0.45 mol) 1-hexadecene was added dropwise via an Orion Model M365 syringe pump over a 170 min. period of time. At the completion of addition the reaction mixture was allowed to stir an additional 40 min. The crude reaction was filtered through a medium porosity glass fritted funnel giving 254.6 g of a clear filtrate (water white) and 5.27 g of a light amber solid. The filtrate was transferred to a 1 L flask and using Kugelrohr distillation the low boiling materials, i.e., unreacted starting materials, were removed at 112-214°C at 1.5-1.75 torr leaving 173.4 g of product as a clear water white oil. The product was characterized by GCMS as several isomers of mono-hexadecyldiphenyl oxide m/z = 394 (M⁺) . By HPLC analysis the product contained, 0.73% DPO, 98.2% mono-hexadecyldiphenyl oxide and 0.95% di- hexadecyldiphenyl oxide. IR spectrum: (Neat) 2956, 2854, 1590, 1505, 1489, 1239 and 750 cm^"1. EXAMPLE 3

Metered Reaction with Biphenyl

A 250mL Morton flask was fitted with an overhead mechanical stirrer, a nitrogen inlet (static nitrogen atmosphere) , a thermocouple for internal temperature measurement and an inlet for 1-hexadecene introduction. The flask was charged with 1.12 g 500PN catalyst (approximately 1 weight percent of the total of the amount of biphenyl and the total amount of 1-hexadecene) which had been calcined at 400°C for 5 hr. Under a nitrogen atmosphere the catalyst was heated to

100-105°C to which was added 61.5 g (0.4 mol) biphenyl and this was further heated to 183 °C . Under nitrogen and at 183°C, 48.6 g (at 92%, 0.2 mol) 1-hexadecene was added dropwise via an Orion Model M365 syringe pump over a 170 min. period of time. At the completion of addition the reaction mixture was allowed to stir an additional 30 min. The crude reaction was filtered through a medium porosity glass fritted funnel giving 99.5 g of a clear filtrate (water white) and 2.89 g of a light amber solid. The filtrate was transferred to a 500 mL flask and using Kugelrohr distillation the low boiling materials were removed at 102-165°C at 1.5-1.75 torr leaving 75.7 g of product as a clear water white oil. The product was characterized by GCMS as several isomers of mono-hexadecylbiphenyl m/z = 378 (M⁺) . By HPLC analysis the product contained 1.22% biphenyl, 96.0% mono-hexadecylbiphenyl and 2.77% dihexadecylbiphenyl . IR spectrum: (Neat) 2955, 2925, 2853, 1486, 1465 and 697 cm^"1. EXAMPLE 4

Metered Reaction of 1-hexadecene with Naphthalene

A 250mL Morton flask was fitted with an overhead mechanical stirrer, a nitrogen inlet (static nitrogen atmosphere) , a thermocouple for internal temperature measurement and an inlet for 1-hexadecene introduction. The flask was charged with 1.12 g 500PN catalyst (approximately 1.1 weight percent of the total of the amount of naphthalene and the total amount of 1-hexadecene added) which had been calcined at 400°C for 5 hr . Under a nitrogen atmosphere the catalyst was heated to 100-105°C to which was added 51.5 g (0.4 mol) naphthalene and this was further heated to 182 °C. Under nitrogen and at 182°C, 48.7 g (at 92%, 0.2 mol) 1-hexadecene was added dropwise via an Orion Model M365 syringe pump over a 170 min. period of time. At the completion of addition the reaction mixture was allowed to stir an additional 10 min. The crude reaction was filtered through a medium porosity glass fritted funnel giving 96.6 g of a light yellow filtrate and 1.37 g of a light amber solid. The filtrate was transferred to a 500 mL flask and using Kugelrohr distillation the low boiling materials were removed at 90-183°C at 1.5-1.75 torr leaving 63.6 g of product as a clear yellow oil. The product was characterized by GCMS as several isomers of mono-hexadecylnaphthalene m/z = 352 (M⁺) . By HPLC analysis the product contained 95.5% mono-hexadecylnaphthalene and 4.5% unknowns. IR spectrum: (Neat) 2956, 2924, 2853, 1465 and 744 cm^"1. EXAMPLE 5

Alkylated Diphenyl Oxide

The alkylation of diphenyl oxide was carried out in a stirred batch mode with the addition of 1-hexadecene either all at once (batch mode as described in Example 1) or by the controlled metering of the olefin over a 170 min period of time, as described in Example 2. The results using three different zeolite materials at 1 weight % (relative to total weight of all reactants) is given in the three tables below. The zeolites chosen for this reaction were obtained from Zeolyst International.

BB10 is a USY zeolite with ca. 20% of the exchange sites occupied by sodium cations and the remaining sites occupied by protons .

Table 1 Zeolite BB10

The results shown in Table 1 are based on the crude reaction mixture, prior to distillation. Table 1 results are shown graphically in FIG. 1. ^~"

500PN is a USY zeolite with 100% ammonium ions in the exchange sites. Calcination caused a selective desorption of ammonia from some of the sites giving a mixed ammonium/proton system.

Table 2. Zeolite 500 PN

The results shown in Table 2 are based on the crude reaction mixture, prior to distillation. Table 2 results are shown graphically in FIG. 2.

DD-12 is a fully protonated USY zeolite, Table 3. DD-12 Zeolite

The results shown in Table 3 are based on the crude reaction mixture, prior to distillation. Table 3 results are shown graphically in FIG. 3.

In all of the cases above the reaction was carried out at a

1:2 molar ratio of 1-hexadecene to DPO with 1 weight % catalyst (unformed) .

The results above clearly show that the use of several types of USY zeolite could be used to generate alkylated DPO with a high selectivity toward mono-alkylation. Also it is clear from the above data that the metering of olefin to the DPO/catalyst mixture gave complete reaction of olefins at a low level of zeolite, while the bulk addition of olefin quickly deactivated the catalyst prior to completion of the reaction. As known in the prior art, the selectivity of reaction using the fully protonated catalyst was slightly lower than with the use of the two partially cation exchanged zeolites. ^~

The reaction of the fully protonated catalyst did not reach 100% conversion; however, this was not optimized and it is likely that a slightly lower temperature would give a more fully converted material.

The isolation of product was accomplished in high yield by a filtration followed by flash removal of volatile materials including the excess DPO. The heel from the Kugelrohr distillation was a water white liquid which was analyzed by LC, GCMS and IR spectroscopy. A GC trace of the mono- diphenyl oxide region, with each peak verified by GCMS, shows major peaks at 19.24, 19.29, 19.45, 19.69, 20.13, 20.88, 21.89, 22.21, 22.34, 22.53, 22.93, 23.69 and 24.90 minutes. The IR spectra of the isolated material showed major absorbances at 2956, 2854, 1590, 1505, 1489, 1239 and 750 cm^"1. It is not surprising that several isomers of the alkylated diphenyl ether were formed.

The mono- to di- ratio of alkylation products formed was excellent: typically 99:1 to 95:5 depending on catalyst used and is on a molar basis, and is clearly in line with the literature for similar aromatic systems. The identification of the di-alkylated isomer is based on the relative retention time on the HPLC. EXAMPLE 6

Alkylation of Biphenyl

The alkylation of biphenyl was carried out in a similar fashion as that described above in example 5 for diphenyl oxide using the USY catalyst which was selectively calcined to a mixture of ammonium and proton exchanged containing material . The results comparing the batch reaction as in Example 1 vs. metered olefin reactions are tabulated below in Table 4.

Table 4 Biphenyl with 500PN zeolite

The results shown in Table 4 are based on the crude reaction mixture, prior to distillation. Table 4 results are graphically represented in FIG. 4.

The relative difference between batch addition of olefin vs. metered addition is striking and indicates the importance of the metering process. Indeed, as can be seen from the data obtained in the preceding examples yields of product in amounts of 95-98% are readily obtainable by practicing the present invention, Further, the reaction is highly selective, resulting in product containing 5 weight % or less of dialkylated aromatic compounds.

The isolation of product was accomplished in high yield by a filtration followed by flash removal of volatile materials including the excess biphenyl . The heel from the Kugelrohr distillation was a water white liquid which was analyzed by LC, GCMS and IR spectroscopy. A GC trace of the mono-biphenyl region, with each peak verified by GCMS, shows major peaks at 20.63, 20.79, 21.00, 21.43, 22.30, 22.44, 22.65, 23.07, 23.38, 23.79 and 25.05 minutes. The IR spectra of the isolated material showed major absorbances at 2955, 2925, 2853, 1486, 1465 and 697 cm^"1-. It is not surprising that several isomers of the alkylated biphenyl were formed.

The mono- to di- ratio of alkylation products formed was excellent and is clearly in line with the literature for similar aromatic systems. The identification of the di-alkylated isomer is based on the relative retention time on the HPLC.

EXAMPLE 7 Alkylation of Naphthalene

The alkylation of naphthalene was carried out in a similar fashion as that described above in example 5 for diphenyl oxide using the USY catalyst which was selectively calcined to a mixture of ammonium and proton exchanged containing material. The results comparing the batch reaction, as in example 1, vs. metered olefin reactions are tabulated below. Table 5. Naphthalene and 500PN Zeolite

The results shown in Table 5 are based on the crude reaction mixture, prior to distillation. Table 5 results are graphically represented in FIG. 5.

The isolation of product was accomplished in high yield by a filtration followed by flash removal of volatile materials including the excess naphthalene. The heel from the Kugelrohr distillation was a pale yellow liquid which was analyzed by LC, GCMS and NMR spectroscopy. A GC trace of the mono-naphthalene region, with each peak verified by GCMS, shows major peaks at 18.70, 18.92, 19.05, 19.22, 19.55, 19.69, 20.11, 20.77 and 21.09 minutes. The IR spectra showed major absorbances at 2956, 2924, 2853, 1465 and 744 cm^"1. It is not surprising that several isomers of the alkylated naphthalene were formed.

The mono to di ratio of alkylation products (best estimated as a molar ratio) formed was excellent (di- not detected in final product as analyzed by HPLC) and is clearly in line with the literature for similar aromatic systems. The identification of a small peak eluted less than one minute after the monoalkylated product, ca. 4.5% by area peaks, detected in the HPLC has not been made.

The above examples indicate that the alkylation of aromatics with α;-olefins can be carried out with high conversions of olefin and high selectivities toward mono-alkylation by the use of several USY catalysts. The key to achieving such favorable results with the use of low levels of zeolite rests in the metering of olefin to the reaction mixture. This metering process keeps the absolute concentration of olefin in the reaction mixture as low as possible by introducing the olefin at such a rate as to match or nearly match the rate of consumption. It is believed that by keeping the concentration of olefin as low as possible that olefin - olefin reactions are minimized. The olefin - olefin reactions are believed to cause catalyst deactivation.

Claims

1. A process for the preparation of a reaction product ^~ substantially comprising a monoalkylated aromatic compound, said process comprising: combining a zeolite catalyst and an aromatic compound in a reaction chamber; heating the combined zeolite and aromatic compound to a reaction temperature ; adding to the reaction chamber an alpha olefin as an alkylating agent by metered addition, so that the olefin is consumed by chemical reaction with the aromatic compound essentially simultaneously with its addition and the concentration of alpha olefin in the reaction mixture is maintained to as close as zero as possible; and wherein the molar ratio of initially charged aromatic compound: total alpha olefin employed in the reaction, ranges from 1:1 to 10:1.

2. A process according to claim 1, wherein the zeolite is a USY zeolite.

3. A process according to claim 1, wherein the aromatic compound is diphenyl oxide.

4. A process according to claim 1, wherein the alpha-olefin is a C₈ - C₂₀ alpha olefin.

5. A process according to claim 1, wherein the alpha olefin is 1-hexadecene.

6. A process according to claim 1, wherein the reaction temperature is in the range of from 175° to 250°C.

7. A process according to claim 1, wherein the molar ratio of aromatic compound charged to the reaction to total alpha olefin employed is about 5:1 to about 1.5:1.

8. A process according to claim 1, wherein the weight percent of zeolite used is about 3 weight % to about 0.5 weight % based on the total of the amount of aromatic compound used and the total amount of alpha olefin used.

9. A process for producing a reaction product containing substantially mono-alkylaromatic compound, wherein the alkyl group is C₁₂ - C₁₈, comprising: combining about 0.9 to about 1.1 weight % USY zeolite and aromatic compound in a reaction chamber, the about 0.9 to about 1.1 weight % based on the total of the amount of aromatic compound used and the total amount of an alpha olefin used as an alkylating agent; heating the combined zeolite and aromatic compound to a temperature of about 180° - 230°C; adding a C₁₂ - C₁₈ alpha olefin at a controlled rate over a period of time exceeding one hour; wherein the molar ratio of aromatic compound to alpha olefin is about 2.5:1 to about 1.75:1.

10. The process according to claim 9, wherein the alpha olefin is 1-hexadecene.

11. The process according to claim 9, wherein the aromatic compound is diphenyloxide.