WO1993006068A1

WO1993006068A1 - Improved liquid acid alkylation catalyst and isoparaffin:olefin alkylation process

Info

Publication number: WO1993006068A1
Application number: PCT/US1992/008110
Authority: WO
Inventors: Kenneth Joseph Del Rossi; Albin Huss, Jr.
Original assignee: Mobil Oil Corporation
Priority date: 1991-09-25
Filing date: 1992-09-24
Publication date: 1993-04-01
Also published as: AU2679092A

Abstract

An isoparaffin:olefin alkylation catalyst, an isoparaffin:olefin alkylation process, and a method for making the catalyst, which catalyst comprises: (a) a Bronsted acid selected from the group consisting of hydrofluoric acid and the halogenated sulfonic acids; (b) an additive having a Donor Number of from about 1 to about 40, wherein said additive is present in a quantity sufficient to effect deactivation of said Bronsted acid for isoparaffin:olefin alkylation such that the catalytic properties of admixture of said Bronsted acid and said additive, in the absence of superacid promoter are characterized by the conversion of a mixed isoparaffin:olefin stream to product containing less than about 50 weight percent of the trimethylpentanes product; and (c) a superacid promoter in concentration sufficient such that contacting said catalyst composition comprising said Bronsted acid, said additive, and said superacid promoter with a mixed isobutane:2-butene feedstream in an isobutane:2-butene molar ratio of more than about 2:1 under alkylation conversion conditions yields a product containing at least 50 weight percent of the trimethylpentanes product.

Description

_ _

IMPROVED -LIQUID ACID ALKYLATION CATALYST AND ISOPARAFFIN:OLEFIN ALKYLATION PROCESS

The present invention relates to the art of catalytic alkylation. The invention relates to a liquid alkylation catalyst and an isoparaffin:olefin alkylation process. Particularly, the invention provides a liquid alkylation catalyst complex which avoids many of the safety and environmental concerns associated with the handling, storage, and processing

10 of concentrated hydrofluoric acid.

Alkylation is a reaction in which an alkyl group is added to an organic molecule. Thus an isoparaffin can be reacted with an olefin to provide an isoparaffin of higher molecular weight. Industrially, the concept

!5 depends on the reaction of a C_ to C_ olefin with . isobutane in the presence of an acidic catalyst producing a so-called alkylate. This alkylate is a valuable blending component in the manufacture of gasolines due not only to its high octane rating but 0 also to its sensitivity to octane-enhancing additives. Industrial alkylation processes have historically used hydrofluoric or sulfuric acid catalysts under relatively low temperature conditions. Acid strength is preferably maintained at 88 to 94 weight percent by 5 the continuous addition of fresh acid and the continuous withdrawal of spent acid.

Hydrofluoric acid and sulfuric acid alkylation processes share inherent drawbacks including environmental and safety concerns, acid consumption, 0 and sludge disposal. For a general discussion of sulfuric acid alkylation, see the series of three articles by L.F. Albright et al., "Alkylation of Isobutane with C. Olefins", 27 Ind. Encr. Chem. Res.. 381-397, (1988). For a survey of hydrofluoric acid 5 catalyzed alkylation, see 1 Handbook of Petroleum Refining Processes 23-28 (R.A. Meyers, ed. , 1986). Hydrogen fluoride, or hydrofluoric acid (HF) is highly toxic and corrosive. However, it is used as a catalyst in isomerization, condensation, polymerization and hydrolysis reactions. The petroleum industry uses anhydrous hydrogen fluoride primarily as a liquid catalyst for alkylation of olefinic hydrocarbons to produce alkylate for increasing the octane number of gasoline. Years of experience in its manufacture and use have shown that HF can be handled safely, provided the hazards are recognized and precautions taken. Though many safety precautions are taken to prevent leaks, massive or catastrophic leaks are feared primarily because the anhydrous acid will fume on escape creating a vapor cloud that can be spread for some distance. Previous workers in this field approached this problem from the standpoint of containing or neutralizing the HF cloud after its release.

U.S. Patents 4,938,935 and 4,985,220, as well as U.S. Patent 4,938,936 teach various methods for containing and/or neutralizing HF acid clouds following accidental releases.

But it would be particularly desirable to provide an additive which decreases the cloud forming tendency of HF without compromising its activity as an isoparaffin:olefin alkylation catalyst. Solvents and complexing agents for hydrofluoric acid complexes have, in the past, been disclosed for various purposes as noted in the following references. U.S. Patent 2,615,908 teaches thioether-HF-copper complex compounds and a method for preparing the same. Potential uses for the thioether-HF-copper complex compounds are listed from column 6, line 55 through column 8 at line 3. The method is said to be useful for purifying HF-containing vent gases from an industrial HF alkylation plant. See column 7, lines 10-24. U.S. Patent 3,531,546 discloses a HF-C0₂ catalyst complex which is said to be useful for alkylation as well as olefin iso erization.

U.S. Patent 3,795,712 relates to acid catalysts comprising a Lewis acid, a Bronsted acid, and a sulfone of the formula R-S0--R' , where R and R¹ are each separately a monovalent radical containing from 1 to 8 carbon atoms or form together a divalent radical having from 3 to 12 carbon atoms.

U.S. Patent 3,856,764 teaches an olefin polymerization catalyst comprising (1) at least one organoaluminum compound, (2) at least one nickel compound selected from the class consisting of nickel salts of carboxylic acids, organic complex compounds of nickel, or nickel tetracarbonyl and (3) at least one hydrogen fluoride complex prepared by complexing hydrogen fluoride with a member of the class consisting of ketones, ethers, esters, alcohols, nitriles, and water. U.S. Patent 4,636,488 discloses an anhydrous nonalcoholic alkylation catalyst comprising a mixture of a mineral acid and an ether in proportions of from about 50 to about 99 weight percent of mineral acid and from about 1 to about 50 weight percent of ether. Useful mineral acids include HF; see column 4 at lines 56-60.

Promoters such as alcohols, thiols, water, ethers, thioethers, sulfonic acids, and carboxylic acids are disclosed in combination with Bronsted acids such HF, fluorosulfonic and trihalomethanesulfonic acids in U.S. Patent 3,778,489. The promoters are said to modify the activity of the Bronsted acids for alkylation. U.S. Patent 3,795,712 teaches hydrocarbon alkylation in the presence of a sulfone and from 10 —5 to 5 moles of hydrofluoric acid per liter of sulfone.

U.S. Patents 4,025,577 and 4,094,924 teach isoparaffin:olefin alkylation catalysts comprising a hydrogen halide a d a metal floride, and, optionally, a suitable diluent.

The preceding references describe catalyst complexes containing Bronsted acids which are useful as catalysts for various reactions. In view of the increasing safety and environmental concerns surrounding the cloud-forming tendency of hydrofluoric acid, providing an additive to mitigate Bronsted acid cloud formation while preserving the properties of the Bronsted acid for isoparaffin:olefin alkylation would be a major advance in the art.

The present invention is directed to a catalyst composition for alkylation of an isoparaffin with an olefin comprising: (a) hydrofluoric acid;

(b) an additive having a Donor Number of from about 1 to about 40 in admixture with said hydrofluoric acid, wherein said additive is present in a quantity sufficient to effect deactivation of said Bronsted acid for isoparaffin:olefin alkylation such that the catalytic properties of said admixture of said hydrofluoric acid and said additive, in the absence of superacid promoter are characterized by the conversion of a mixed isoparaffin:olefin stream to product containing more than about 0.1 weight percent of alkyl halide; and

(c) a superacid promoter in concentration sufficient such that contacting said catalyst composition comprising said hydrofluoric acid, said additive, and said superacid promoter with a mixed isobutane:2-butene feedstream in an isobutane:2-butene molar ratio of more than about 2:1 under alkylation conversion conditions yields a product containing at least 50 percent of the trimethylpentanes obtained by contacting said isobutane:2-butene feedstream with concentrated HF under said alkylation conversion conditions. The invention provides, in a first aspect, a catalyst composition for alkylation of an isoparaffin with an olefin comprising:

(a) hydrofluoric acid; (b) an additive having a Donor Number of from about 1 to about 40 in admixture with said hydrofluoric acid, wherein said additive is present in a quantity sufficient to effect deactivation of said hydrofluoric acid for isoparaffin:olefin alkylation such that the catalytic properties of said admixture of said hydrofluoric acid and said additive, in the absence of superacid promoter are characterized by the conversion of a mixed isoparaffin:olefin stream to product containing more than about 0.1 weight percent of alkyl halide; and

(c) a superacid promoter in concentration sufficient such that contacting said catalyst composition comprising said hydrofluoric acid, said additive, and said superacid promoter with a mixed isobutane:2-butene feedstream in an isobutane:2-butene molar ratio of more than about 2:1 under alkylation conversion conditions yields a product containing at least 50 weight percent of the trimethylpentanes obtained by contacting said isobutane:2-butene feedstream with concentrated HF under said alkylation conversion conditions.

The invention further provides, in a second aspect, a catalyst composition for alkylation of an isoparaffin with an olefin comprising: (a) a halogenated sulfonic acid;

(b) an additive having a Donor Number of from about 1 to about 40 in admixture with said halogenated sulfonic acid, wherein said additive is present in a quantity sufficient to effect deactivation of said halogenated sulfonic acid for isoparaffin:olefin alkylation such that the catalytic properties of said admixture of said halogenated sulfonic acid and said additive, in the absence of superacid promoter are characterized by the conversion of a mixed isoparaffin: olefin stream to product containing less than about 50 weight percent of the trimethylpentanes obtained by contacting said mixed isoparaffin:olefin stream with neat halogenated sulfonic acid under said alkylation conversion conditions; and

(c) a superacid promoter in concentration sufficient such that contacting said catalyst composition comprising said halogenated sulfonic acid, said additive, and said superacid promoter with a mixed isobutane:2-butene feedstream in an isobutane:2-butene molar ratio of more than about 2:1 under alkylation conversion conditions yields a product containing at least 50 weight of the trimethylpentanes obtained by contacting said isobutane:2-butene feedstream with concentrated halogenated sulfonic acid under said alkylation conversion conditions.

The invention further provides a process for alkylating an isoparaffin with an olefin comprising contacting at least one isoparaffin and at least one olefin with a catalyst composition of the invention under alkylation conversion conditions.

The Figure shows weight percent trimethylpentanes (the y-axis) as a function of mole percent promoter in HF (the x-axis) for HF in sulfolane additive together with superacid promoters: TaF with 40/60 wt/wt HF/sulfolane (inverted triangular datapoints) , SbF₅ with 40/60 wt/wt HF/sulfolane (triangular datapoints) , BF_ with 20/80 wt/wt HF/sulfolane (rectangular datapoints) , BF₃ with 40/60 wt/wt HF/sulfolane (circular datapoints) .

The invention provides a liquid isoparaffin:olefin alkylation catalyst composition which provides commercially useful levels of isoparaffin:olefin alkylation activity while avoiding safety and environmental concerns attendant to the storage, transfer, and processing of concentrated HF. As used herein, the terms "concentrated HF" and "concentrated hydrofluoric acid" refer to hydrofluoric acid solutions containing more than about 96 weight percent HF. Feedstocks useful in the present alkylation process include at least one isoparaffin and at least one olefin. The isoparaffin reactant used in the present alkylation process has from about 4 to about 8 carbon atoms. Representative examples of such isoparaffins include isobutane, isopentane,

3-methylhexane, 2-methylhexane, 2,3-dimethylbutane and 2,4-dimethylhexane.

The olefin component of the feedstock includes at least one olefin having from 2 to 12 carbon atoms. Representative examples of such olefins include butene-2, isobutylene, butene-1, propylene, ethylene, pentene, hexene, heptene, and octene, merely to name a few. The preferred olefins include the C. olefins, for example, butene-1, butene-2, isobutylene, or a mixture of one or more of these C. olefins, with butene-2 being the most preferred. Suitable feedstocks for the process of the present invention are described in U.S. Patent 3,862,258 to Huang et al. at column 3, lines 44-56, the disclosure of which is incorporated by reference as if set forth at length herein.

The molar ratio of isoparaffin to olefin is generally from about 1:1 to about 100:1, preferably from about 1:1 to about 50:1, and more preferably from about 5:1 to about 20:1.

The term "donicity" describes the propensity of a solvent to donate electron pairs to acceptor solutes.

The term "Donor Number" (DN) as used herein is a measure of donicity, and is defined as the negative of

-1 the enthalpy change, measured in Kcal-mol , for the reaction of the additive with SbCl. _-> to form a 1:1 adduct, where both reactants are in dilute solution in 1,2-dichloroethane (DCE) . For a discussion of donicity and Donor Numbers, see Y. Marcus, "The Effectivity of Solvents as Electron Pair Donors", 13 Journal of Solution Chemistry 599 (1984) . The Table below, reports donor numbers listed in the Marcus article for various solvents.

Additives useful in the present invention include nitroalkanes, (e.g., nitromethane and 1-nitropropane) , carbonates, (e.g., dimethylcarbonate, propylene carbonate tetrachloroethylene carbonate) having the formula ROC(O)OR or i ₁

ROC(0)0, wherein R is an alkyl or an alkyl halide, or an aromatic or halogenated aromatic group having from about 1 to about 30 carbon atoms, of which propylene carbonate _\ [ (C₃H_gOC(0)0) is a particularly preferred carbonate with tetrachloro¬ ethylene carbonate as an example of a suitable alkyl halide-containing carbonate additive. Useful additives also include perhalogenated alkanes (e.g., perfluorodecalin) , halogenated alcohols (e.g.,

2,2,2-trifluoroethanol) , sulfonic acids having the formula R-SO H, wherein R is an aromatic group or a linear, branched, cyclic, or polycyclic alkyl group containing from about 1 to about 30 carbon atoms (e.g., methanesulfonic acid, ethanesulfonic acid, propane- sulfonic acid, hexanesulfonic acid, cyclohexanesulfonic acid, adamantanesulfonic acid, benzenesulfonic acid and other branched, straight chain, monocyclic, and polycyclic aromatic sulfonic acids) . Additional useful additives include the sulfones (e.g., a sulfone having the formula R-S0₂-R' wherein R and R¹ are the same or different alkyl or halogenated alkyl groups, of which one example comprises sulfolane) , as well as acetyl chloride, benzoyl fluoride, methyl propionate, sulfuryl chloride, and sulfuryl chloride fluoride.

Donor Numbers for some of these useful additives are listed below in Table 1. Table 1

Additive DN Additive DN

Thus additives useful in the present invention are characterized by Donor Numbers of from about 1. to about 40, preferably less than about 30, more preferably less than about 16. While additives characterized by lower Donor Numbers are preferred, it is to be understood that solvents having higher Donor Numbers within the range of about 1 to about 40 are also useful. Examples of such useful additives include amines such as pyridine and ammonia compounds as well as alcohols such as methanol and ethanol.

The catalyst composition of the invention typically contains from about 10 to about 90 weight percent of a Bronsted acid selected from the group consisting of hydrofluoric acid and the halosulfonic acids, preferably from about 20 to about 80 weight percent of the Bronsted acid, and more preferably from about 40 to about 60 weight percent of the Bronsted acid. Additive content in the catalyst composition of the invention typically ranges from about 10 to about 90 weight percent, preferably from about 20 to about 80 weight percent, and more preferably from about 40 to about 60 weight percent of additive. Useful promoter concentrations vary with the relative concentrations of Bronsted acid and additive, with the superacid promoter typically being present in molar ratios of superacid promoter:Bronsted acid from about 1:200 to about 1:1, preferably from about 1:100 to about 1:2.

The purpose of formulating a liquid alkylation catalyst containing both a Bronsted acid as well as a superacid promoter in accordance with the present invention is (as noted above) to mitigate the cloud forming tendency of the Bronsted acid while preserving isoparaffin:olefin alkylation activity. Determining the extent to which a selected Bronsted acid must be diluted with a selected additive within the concentration ranges disclosed above to achieve the desired reduction in vapor pressure (and cloud forming tendency) requires only a minor amount of trial and error.

The catalyst composition of the present invention, may be readily substituted for the concentrated hydrofluoric acid catalyst in an existing hydrofluoric acid alkylation process without substantial equipment modifications. Accordingly, the conversion conditions for the process of the present invention resemble those of typical commercial hydrofluoric acid alkylation processes.

The present alkylation process is suitably conducted at temperatures of from about 10 to about 500°C, preferably from about 10 to about 200°C, and more preferably from about 20^βC to about 60°C. Pressure is maintained to ensure a liquid phase in the alkylation reaction zone. Pressures typically range from about 20 to about 1200 psig, preferably from about 50 to about 500 psig. Olefin feed rates generally range from about 0.01 to about 10 WHSV and more preferably from about 0.05 to about 5 hr WHSV. The mixed isoparaffin:olefin reactants may be contacted with the catalyst composition of the invention in any suitable reaction vessel, examples of which include stirred-tank reactors as well as riser-type reactors. Contact time for the mixed isoparaffin:olefin feed and the catalyst composition of the invention typically are within the range of from about 0.1 second to about 100 minutes, and more preferably from about 10 seconds to about 20 minutes.

The superacid promoter, the Bronsted acid, and the additive components of the alkylation catalyst composition may be added by injection directly into the alkylation process unit, or may be mixed with the hydrocarbon charge, or may be mixed with the fresh and/or the circulating catalyst, or with a stream of mixed acid/additive catalyst. Downstream from the alkylation reaction zone, the catalyst mixture is preferably separated from the alkylate product stream, mixed with fresh and/or circulating catalyst, and recycled to the alkylation reaction zone. The particular separation technique selected, however, depends upon the characteristics of the catalyst, and in particular the combination of Bronsted acid, additive, and superacid promoter selected in accordance with the present invention.

EXAMPLE 1 The alkylation performance of HF (99+%, Matheson) was determined for comparison with ternary HF/ additive/promoter mixtures. HF (40 grams) was condensed into a clean, dry 1000 cc autoclave. The autoclave was warmed to room temperature (71°F) . Isobutane (100 grams, Matheson) was added, the autoclave was pressurized to 100 psig and stirred at 1500 rpm. A pre- ixed 10/1 wt/wt isobutane/2-butene feed (Matheson) was then introduced at 250 cc/hr. A 10-12°F temperature rise was observed during feed addition. After two hours, feed addition was halted and a 300 cc liquid sample was obtained. The liquid sample was depressured through an ice cooled trap

(filled with 50 cc of water) which was connected to a gas sampling bomb and wet test meter. Liquid alkylate and gas samples were analyzed with a Varian 6000 gas chromatograph equipped with a 60 meter DB-1 capillary column.

EXAMPLE 2 1-Nitropropane (60 grams, Aldrich Chemical Co.) was loaded into a clean, dry 1000 cc autoclave under a nitrogen atmosphere. The autoclave was sealed, and cooled with liquid nitrogen. The autoclave was evacuated and 40 grams of anhydrous- HF (Matheson) were condensed into the autoclave. The HF/1-nitropropane mixture was warmed to room temperature (71°F) . Isobutane (100 grams, Matheson) was added to the mixture, the autoclave was pressurized to 100 psig and stirred at 1500 rpm. A pre-mixed 10/1 wt/wt isobutane/2-butene feed (Matheson) was then introduced at 250 cc/hr. A 2-3^βF temperature rise was observed during feed addition. After two hours, feed addition was halted and a 300 cc liquid sample was obtained. The liquid sample was depressured through an ice cooled trap (filled with 50 cc of water) which was connected to a gas sampling bomb and wet test meter. A gas product was collected and analyzed with a Varian 6000 gas chromatograph equipped with a 60 meter DB-1 capillary column. The GC analysis showed only butyl fluoride, C.H_gF, with no detectable C_g+ hydrocarbons.

EXAMPLE 3 The identical procedure as in Example 2 was performed except 5 grams of fluorosulfonic acid (Aldrich Chemical Co.) were added to the

HF/1-nitropropane mixture. A 10-12°F temperature rise was observed during feed addition, and a water-white liquid was obtained. The total product composition is compared with the product from Example 1, the HF base case run, in Table 2.

The results show that addition of a superacid promoter, such as fluorosulfonic acid, to an inactive HF/additive mixture can restore alkylation performance to levels near that of concentrated HF.

(1) Only butyl fluoride produced, no detectable C_g+ alkylate product.

EXAMPLE 4-20 Examples 4-20 were conducted with sulfolane as the representative additive. These examples showed the importance of additive concentration, promoter concentration and type of promoter on ternary catalyst performance.

In a typical experiment, sulfolane (60 grams, Phillips Petroleum Co.) was loaded into a clean, dry 1000 cc autoclave under a nitrogen atmosphere. Liquid or solid superacid promoters were also added to the autoclave under a nitrogen atmosphere. Sulfolane was stored in a vacuum desiccator over P₂0_g prior to use. The autoclave was sealed and cooled with liquid nitrogen. The autoclave was evacuated and 40 grams of anhydrous HF (Matheson) were condensed into the autoclave. The HF/sulfolane/promoter mixtures were warmed to room temperature (71°F) . Isobutane (100 grams, Matheson) was added to the mixture, the autoclave was pressurized to 100 psig and stirred at 1500 rpm. A pre- ixed 10/1 wt/wt isobutane/2-butene feed (Matheson) was then introduced at 250 cc/hr. A temperature rise was typically observed (3-12°F) during feed addition. After two hours, feed addition was halted and a 300 cc liquid sample was obtained. The liquid sample was depressured through an ice cooled trap (filled with 50 cc of water) which was connected to a gas sampling bomb and wet test meter. Liquid alkylate and gas samples were analyzed with a Varian 6000 gas chromatograph equipped with a 60 meter DB-1 capillary column.

. In the absence of promoter, 40/60 wt/wt HF/ sulfolane produced only butyl fluoride (Example 4) . However, addition of superacid promoters restored activity to near original HF levels. The Figure shows results from promoted HF/sulfolane catalysts. Yield of trimethylpentanes (the primary alkylation product) is plotted as a function of promoter concentration in HF. Yield of trimethylpentanes with pure HF catalyst (80 wt%) is given as a reference. Stronger acids, like antimony pentafluoride

(Examples 5-8) or tantalum pentafluoride (Examples 9-12) , were most effective at restoring alkylation activity. HF/sulfolane mixtures (40/60 wt/wt) with about 1.5 mol% of either promoter (based on HF) gave HF-like performance.

Table 3

Example 4 5 _ 6 _ 7 _R 8 _ 9 _p. lO_p. 11 12_

Promoter None SbF SbF SbF SbF TaF TaF TaF TaF

HF/Sulfolane Ratio 5 (wt/wt) 40/60 40/60 40/60 40/60 40/60 40/60 40/60 40/60 40/60

Mole % Promoter in HF 0 0.5 0.9 1.4 1.8 0.7 1.1 1.4 2.1

Trimethylpentane

Yield (wt%) . 0.0 29.5 36.3 69.5 71.3 0.0 45.8 71.2 81.7

10

Example Promoter

HF/Sulfolane Ratio ( t/wt) 40/60 40/60 40/60 40/60 40/60 20/80 20/80 20/80 Mole % Promoter in HF 1.4 2.9 4.2 6.2 8.1 4.2 8.1 11.7

15 Trimethylpentane Yield (wt%) 39.5 66.9 74.0 67.3 68.8 28.0 32.7 40.0

Boron trifluoride (Examples 13-17) at a concentration of about 4 mol% was required to restore catalyst activity to near HF levels.

Alkylation data with BF_-promoted 20/80 wt/wt HF/sulfolane (Examples 18-20) are also shown in Figure 1. BF_ promotion of the 20/80 wt/wt mixture was less effective, and alkylation performance did not approach pure HF.

Changes and modifications in the specifically described embodiments can be carried out without departing from the scope of the invention which is intended to be limited only by the scope of the appended claims.

Claims

CLAIMS :

1. A catalyst composition for alkylation of an isoparaffin with an olefin comprising:

(a) hydrofluoric acid;

(c) a superacid promoter in concentration sufficient such that contacting said catalyst composition comprising said hydrofluoric acid, said additive, and said superacid promoter with a mixed isobutane:2-butene feedstream ih an isobutane:2-butene molar ratio of more than about 2:1 under alkylation conversion conditions yields a product containing at least 50 percent of the trimethylpentanes obtained by contacting said isobutane:2-butene feedstream with concentrated HF under said alkylation conversion conditions.

2. The catalyst composition of claim 1 wherein said additive is characterized by a Donor Number of less than about 30.

3. The catalyst composition of claim 2 wherein said additive is chracterized by a Donor Number of less than about 16.

4. The catalyst composition of claim 3 wherein said additive is selected from the group consisting of acetyl halides, benzoyl halides, phosphorous oxyhalides, alkyl sulfites, anhydrides, esters, and sulfuryl halides.

5. The catalyst composition of claim 1 comprising from about 10 to about 90 weight percent of said additive.

6. The catalyst composition of claim 5 comprising from about 20 to about 80 weight percent of said additive.

7. The catalyst composition of claim 1 wherein said additive is selected from the group consisting of sulfones, nitroalkanes, alkyl carbonates, perhalogenated alcohols and alkylsulfonic acids.

8. A process for alkylating an isoparaffin with an olefin comprising effecting reaction of isoparaffin and olefin with an alkylation catalyst composition comprising: (a) hydrofluoric acid;

(b) an additive having a Donor Number of from about 1 to about 40 in admixture with said hydrofluoric acid, wherein said additive is present in a quantity sufficient to effect deactivation of said Bronsted acid for

• isoparaffin:olefin alkylation such that the catalytic properties of said admixture of said hydrofluoric acid and said additive, in the absence of superacid promoter are characterized by the conversion of a mixed isoparaffin:olefin stream to product containing more than about 0.1 weight percent of alkyl halide; and

9. The process of claim 8 wherein said additive is characterized by a Donor Number of less than about 30.

10. The process of claim 9 wherein said additive is characterized by a Donor Number of less than about 16.

11. The process of claim 9 wherein said additive is selected from the group consisting of acetyl halides, benzoyl halides, phosphorous oxyhalides, alkyl sulfites, anhydrides, esters, and sulfuryl halides.

12. The process of claim 9 wherein said additive is selected from the group consisting of sulfones, nitroalkanes, alkyl carbonates, perhalogenated alcohols and alkylsulfonic acids.

13. The process of claim 8 wherein said additive comprises from about 10 to about 90 weight percent of said catalyst composition.

14. The process of claim 13 wherein said additive comprises from about 20 to about 80 weight percent of said catalyst composition.

15. The process of claim 8 further comprising charging said isoparaffin and said olefin to a riser reactor containing said catalyst composition.

16. An alkylation catalyst composition comprising:

(a) at least one halogenated sulfonic acid;

(b) an additive having a Donor Number of from about 1 to about 40 in admixture with said halogenated sulfonic acid, wherein said additive is present in a quantity sufficient to effect deactivation of said halogenated sulfonic acid for isoparaffin:olefin alkylation such that the catalytic properties of said admixture of said Bronsted acid and said additive, in the absence of superacid promoter are characterized by the conversion of a mixed isoparaffin:olefin stream to product containing less than about 50 weight percent of the trimethylpentanes obtained by contacting said mixed isoparaffin:olefin stream with said halogenated sulfonic acid under said alkylation conversion conditions; and

(c) a superacid promoter in concentration sufficient such that contacting said liquid alkylation catalyst composition with a mixed isobutane:2-butene feedstream in an isobutane:2-butene molar ratio of more than about 2:1 under alkylation conversion conditions yields a product containing at least 50 weight percent of the trimethylpentanes obtained by contacting said isobutane:2-butene feedstream with said halogenated sulfonic acid under said alkylation conversion conditions.

17. The catalyst composition of claim 16 wherein said additive is characterized by a Donor Number of less than about 30.

18. The catalyst composition of claim 16 wherein said additive is chracterized by a Donor Number of less than about 16.

19. The catalyst composition of claim 16 wherein said additive is selected from the group consisting of acetyl halides, benzoyl halides, phosphorous oxyhalides, alkyl sulfites, anhydrides, esters, and sulfuryl halides.

20. The catalyst composition of claim 16 comprising from about 10 to about 90 weight percent of said additive.

21. The catalyst composition of claim 20 comprising from about 20 to about 80 weight percent of said additive.

22. The catalyst composition of claim 16 wherein said additive is selected from the group consisting of sulfones, nitroalkanes, alkyl carbonates, perhalogenated alcohols and alkylsulfonic acids.

23. A process for alkylating as isoparaffin with an olefin comprising effecting reaction of isoparaffin and olefin with an alkylation catalyst composition comprising: (a) at least one Bronsted acid selected from the group consisting of hydrofluoric acid and the halogenated sulfonic acid;

(b) an additive having a Donor Number of from about 1 to about 40 in admixture with said Bronsted acid, wherein said additive is present in a quantity sufficient to effect deactivation of said Bronsted acid for isoparaffin:olefin alkylation such that the catalytic properties of said admixture of said Bronsted acid and said additive, in the absence of superacid promoter are characterized by the conversion of a mixed isoparaf in:olefin stream to product containing less than about 50 weight percent of the trimethylpentanes obtained by contacting said mixed isoparaffin:olefin stream with concentrated HF under said alkylation conversion conditions; and

(c) a superacid promoter in concentration sufficient such that contacting said liquid alkylation catalyst composition with a mixed isobutane:2-butene feedstream in an isobutane:2-butene molar ratio of more than about 2:1 under alkylation conversion conditions yields a product containing at least 50 weight percent of the trimethylpentanes obtained by contacting said isobutane:2-butene feedstream with concentrated HF under said alkylation conversion conditions.

24. The process of claim 23 wherein said additive is characterized by a Donor Number of less than about 30.

25. The process of claim 24 wherein said additive is characterized by a Donor Number of less than about 16.

26. The process of claim 23 wherein said additive is selected from the group consisting of acetyl halides, benzoyl halides, phosphorous oxyhalides, alkyl sulfites, anhydrides, esters, and sulfuryl halides.

27. The process of claim 23 wherein said additive is selected from the group consisting of sulfones, nitroalkanes, alkyl carbonates, perhalogenated alcohols and alkylsulfonic acids.

28. The process of claim 23 wherein said additive comprises from about 10 to about 90 weight percent of said catalyst composition.

29. The process of claim 28 wherein said additive comprises from about 20 to about 80 weight percent of said catalyst composition.

30. The process of claim 23 further comprising charging said isoparaffin and said olefin to a riser reactor containing said catalyst composition.