Selective alkylation of aromatic hydrocarbons

1. A method for increasing selectivity of aromatic alkylation to monoalkylation comprising:

providing a feedstream consisting essentially of a concentration of alkylating agent and a stoichiometric excess of benzene, said alkylating agent consisting essentially of a molar blend of propylene and one or more linear butene(s); and,

contacting said feedstream with a catalytically effective amount of zeolite beta under alkylation reaction conditions which increase selectivity of the alkylation to monoalkylation compared to predicted selectivity to monoalkylation based on the concentration of the alkylating agent and on the molar blend of propylene and one or more linear butene(s).

2. The method of claim 1 further comprising:

providing said concentration of from about 1 to about 4 mole percent alkylating agent, said alkylating agent comprising about 200 ppm or less isobutylene;

providing from about a 1:4 to about a 4:1 molar blend of propylene to one or more linear butene(s); and,

maintaining a reaction temperature which minimizes skeletal isomerization of the one or more linear butene(s) to isobutylene.

3. The method of claim 1 producing actual total moles of di- and tri-alkylated aromatic compounds at molar ratios of propylene:linear butene(s) of from about 1:4 to about 4:1, said actual total moles being at least 10% less than projected total moles of di- and tri-alkyl benzenes per 100 g product predicted based on the concentration of alkylating agent and the molar blend of propylene and one or more linear butene(s).

4. The method of claim 1 further comprising providing the one or more linear butene(s) comprising 100 ppm or less isobutylene.

5. The method of claim 1 wherein said conditions comprise:

a reaction temperature of from about 100° C. to about 150° C.; and,

a reaction pressure of from about 250 psig to about 350 psig.

6. The method of claim 3 wherein said conditions comprise:

a reaction temperature of from about 110° C. to about 145° C.; and,

a reaction pressure of from about 270 psig to about 325 psig;

a total liquid feed rate of about 40 g/hr to about 200 g/hr for about 25 g total weight of catalyst, based on combined weight of zeolite beta catalyst powder and binder.

7. The method of claim 5 , said conditions producing:

conversion of 99% or more of said concentration of one or more linear butene(s); and,

conversion of 99% or more of said concentration of propylene.

8. The method of claim 6 , said conditions producing:

conversion of 99% or more of said concentration of one or more linear butene(s); and,

conversion of 99% or more of said concentration of propylene.

9. The method of claim 6 , said conditions producing

conversion of 99.9% or more of said concentration of one or more linear butene(s); and,

conversion of 99.9% or more of said concentration of propylene.

10. The method of claim 1 further comprising producing

selectivity to sec-butylbenzene of about 98% or more; and,

selectivity to cumene of about 95% or more.

11. The method of claim 1 further comprising producing

selectivity to sec-butylbenzene of about 99% or more; and,

selectivity to cumene of about 97% or more.

12. The method of claim 1 further comprising producing

selectivity to sec-butylbenzene of about 99.5% or more; and,

selectivity to cumene of about 97% or more.

13. A method for increasing selectivity of aromatic alkylation to monoalkylation comprising:

providing a feedstream consisting essentially of a concentration of alkylating agent and a stoichiometric excess of benzene, said alkylating agent consisting essentially of a molar blend of propylene and one or more linear butene(s); and,

contacting said feedstream with a catalytically effective amount of zeolite beta under alkylation reaction conditions producing actual total moles of di- and tri-alkylated aromatic compounds per 100 g product at molar ratios of propylene:linear butene(s) of from about 1:4 to about 4:1, said actual total moles being at least 10% less than projected total moles of di- and tri-alkyl benzenes per 100 g product predicted based on the concentration of alkylating agent and the molar blend.

14. The method of claim 13 producing actual total moles of di- and tri-alkylated aromatic compounds per 100 g product at molar ratios of propylene:linear butene(s) of from about 1:4 to about 4:1, said actual total moles being at least 30% less than projected total moles of di- and tri-alkyl benzenes per 100 g product predicted based on the concentration of alkylating agent and the molar blend.

15. The method of claim 13 further comprising:

providing said concentration comprising from about 1 to about 4 mole percent alkylating agent, said alkylating agent comprising about 200 ppm or less isobutylene;

providing from about a 1:4 to about a 4:1 molar blend of propylene to one or more linear butene(s);

maintaining a reaction temperature of from about 100° C. to about 150° C.; and,

maintaining a reaction pressure of from about 250 psig to about 350 psig.

16. The method of claim 14 further comprising:

providing said concentration comprising from about 1 to about 4 mole percent alkylating agent, said alkylating agent comprising about 200 ppm or less isobutylene;

providing from about a 1:4 to about a 4:1 molar blend of propylene to one or more linear butene(s);

maintaining a reaction temperature of from about 100° C. to about 150° C.; and,

maintaining a reaction pressure of from about 250 psig to about 350 psig.

17. A method for increasing selectivity of aromatic alkylation to monoalkylation comprising:

providing a feedstream consisting essentially of alkylating agent and a stoichiometric excess of benzene, said alkylating agent consisting essentially of a molar blend of propylene and one or more linear butene(s); and,

contacting said feedstream with a catalytically effective amount of zeolite beta under alkylation reaction conditions which increase selectivity of the alkylation to monoalkylation compared to predicted selectivity to monoalkylation based on the concentration of the alkylating agent and on the molar blend of propylene and one or more linear butene(s), producing an alkylator product stream;

removing benzene from said alkylator product stream, producing a benzene-depleted stream; and

recovering said monoalkylated benzene from said benzene-depleted stream.

18. The method of claim 17 producing actual total moles of di- and tri-alkylated aromatic compounds per 100 g product at molar ratios of propylene:linear butene(s) of from about 1:4 to about 4:1, said actual total moles being at least 20% less than projected total moles of di- and tri-alkyl benzenes per 100 g product predicted based on the concentration of alkylating agent and the molar blend.

19. The method of claim 17 producing actual total moles of di- and tri-alkylated aromatic compounds per 100 g product at molar ratios of propylene:linear butene(s) of from about 1:4 to about 4:1, said actual total moles being at least 30% less than projected total moles of di- and tri-alkyl benzenes per 100 g product predicted based on the concentration of alkylating agent and the molar blend.

20. The method of claim 17 further comprising

removing light ends and water from said alkylator product, producing a light ends column stream;

recycling said benzene removed from said alkylator product stream to said alkylator.

21. The method of claim 20 where said recovering said monoalkylated benzene produces a remainder, said method further comprising separating a dialkyl benzene stream from said remainder.

22. The method of claim 21 further comprising

contacting said remainder with a transalkylation catalyst under conditions effective to produce supplemental monoalkylated benzene;

recovering said supplemental monoalkylated benzene.

23. The method of claim 22 further comprising removing light ends and water from said alkylator product, producing a light ends column stream.

24. The method of claim 23 further comprising recycling said benzene removed from said alkylator product stream to said alkylator.

25. The method of claim 17 further comprising:

providing said concentration comprising from about 1 to about 4 mole percent alkylating agent, said alkylating agent comprising about 200 ppm or less isobutylene;

providing from about a 1:4 to about a 4:1 molar blend of propylene to one or more linear butene(s);

maintaining a reaction temperature of from about 100° C. to about 150° C.; and,

maintaining a reaction pressure of from about 250 psig to about 350 psig.

26. The method of claim 24 further comprising:

providing said concentration comprising from about 1 to about 4 mole percent alkylating agent, said alkylating agent comprising about 200 ppm or less isobutylene;

providing from about a 1:4 to about a 4:1 molar blend of propylene to one or more linear butene(s);

maintaining a reaction temperature of from about 100° C. to about 150° C.; and,

maintaining a reaction pressure of from about 250 psig to about 350 psig.

27. The method of claim 17 said conditions producing:

conversion of 99% or more of said concentration of one or more linear butene(s); and,

conversion of 99% or more of said concentration of propylene.

28. The method of claim 26 , said conditions producing

conversion of 99.9% or more of said concentration of one or more linear butene(s); and,

conversion of 99.9% or more of said concentration of propylene.

29. The method of claim 22 further comprising providing said transalkylation catalyst selected from the group consisting of zeolite Y and solid phosphoric acid.

30. The method of claim 28 further comprising providing said transalkylation catalyst selected from the group consisting of zeolite Y and solid phosphoric acid.

31. The method of claim 17 further comprising producing

selectivity to sec-butylbenzene of about 98% or more; and,

selectivity to cumene of about 95% or more.

32. The method of claim 17 further comprising producing

selectivity to sec-butylbenzene of about 99% or more; and,

selectivity to cumene of about 97% or more.

33. The method of claim 24 further comprising producing

selectivity to sec-butylbenzene of about 99.5% or more; and,

selectivity to cumene of about 97% or more.