Compositions for, solutions for, and methods of use of siloxane based aromatic trisureas as viscosifiers

1. A compound of the following formula:

wherein Z is an aromatic moiety,

a, b, and c are independently integers from 2 to 9,

X 1 , X 2 , X 3 , X 4 , X 5 , X 6 , X 7 , X 8 , and X 9 are independently chosen from

wherein R 1a , R 1b , and R 1c are independently chosen in each instance from —(C 1-5 )alkyl, and

wherein R 2a , R 2b , and R 2c are independently chosen in each instance from —(C 1-5 )alkyl, —OSi((C 1-5 )alkyl) 3 , and —OSi((C 1-5 )alkyl) 2 (OSi((C 1-5 )alkyl) 3 ), or taken together with the Si to which they are attached, any 2 of R 2a , R 2b , and R 2c form a fully alkylated 8 to 12 membered siloxane ring,

wherein R 1d and R 1f are independently each —(C 1-5 )alkyl, and

R 1e is —OSi((C 1-5 )alkyl) 2 (CH 2 ) 1-5 (CH 3 ),

wherein when any one or more of X 4 , X 5 , X 6 , X 7 , X 8 , and X 9 is each

then X 1 , X 2 , and X 3 are each

wherein R 1a , R 1b , and R 1c are each —(C 1-5 )alkyl.

2. The compound of claim 1 , wherein Z is selected from an aromatic ring, a heteroaromatic ring, a polycyclic aromatic ring system, or a polycyclic heteroaromatic ring system.

3. The compound of claim 1 , wherein Z is a (C 6-10 ) aromatic ring or a polycyclic aromatic ring.

4. The compound of claim 1 , wherein X 1 , X 2 , X 3 , X 4 , X 5 , X 6 , X 7 , X 8 , and X 9 are each

5. The compound of claim 1 , wherein two or less of X 1 , X 2 , X 3 , X 4 , X 5 , X 6 , X 7 , X 8 , and X 9 are each

6. The compound of claim 1 , wherein

Z is

a, b, and c are each 3, and

X 1 , X 2 , X 3 , X 4 , X 5 , X 6 , X 7 , X 8 , and X 9 are each

wherein R 1a , R 1b , and R 1c are each —CH 3 .

7. The compound of claim 1 , wherein

Z is

a, b, and c are each 3, and

X 1 , X 2 , X 3 , X 4 , X 5 , X 6 , X 7 , X 8 , and X 9 are each

 wherein R 1a , and R 1c are each —CH 3 and

R 1b is

and wherein R 2a , R 2b , and R 2c taken together with the Si to which they are attached form

8. The compound of claim 1 , wherein

Z is

a, b, and c are each 3,

X 1 , X 2 , X 3 , X 4 , X 5 , and X 6 are each

wherein R 1a , R 1b , and R 1c are —CH 3 ,

X 7 and X 9 are each —CH 3 , and

X 8 is

wherein R 1d and R 1f are —CH 3 , and R 1e is —OSi(CH 3 ) 2 (CH 2 ) 3 (CH 3 ).

9. A solution comprising a volume of dense CO 2 , a compound of claim 1 , and a co-solvent, wherein the solution has a viscosity greater than the viscosity of dense CO 2 .

10. The solution of claim 9 , wherein the co-solvent is a C 3 -C 16 hydrocarbon solvent.

11. A method of increasing viscosity of dense CO 2 comprising:

dissolving a compound in accordance with claim 1 in a co-solvent to form a solution; and

mixing the solution with a volume of dense CO 2 .

12. The method of claim 11 , wherein the compound is an amount between 0.01 and 5 wt. % based on the weight of the resultant mixed solution.

13. The method of claim 12 , wherein the compound is an amount between 0.1 and 1 wt. % based on the weight of the resultant mixed solution.

14. The method of claim 11 , wherein the co-solvent used to dissolve the compound is an amount between 1 and 50 wt. % based on the weight of the resultant mixed solution.

15. The method of claim 11 , wherein the mixing of the solution with a volume of dense CO 2 is performed at a temperature between 20° C. and 100° C., and under pressure within the range of 800 psi and 9000 psi.

16. A method of increasing viscosity of natural gas liquids (NGLs) comprising:

dissolving a compound in accordance with claim 1 in a volume of an NGL to form a solution.

17. The method of claim 16 , wherein the NGL comprises one or more gases selected from a group consisting of propane, butane, iso-butane, pentane, and pentane plus.

18. The method of claim 16 , wherein the compound is an amount between 0.01 and 5 wt. % based on the weight of the resultant solution.

19. The method of claim 16 , wherein the compound is an amount between 0.1 and 1 wt. % based on the weight of the resultant solution.

20. The method of 16 , wherein the dissolving of the compound with a volume of NGL is performed at a temperature between 20° C. and 120° C., and under pressure within the range of 50 psi and 10,000 psi.