Phosphine-oxide catalyzed process of production of hydrogen from silylated derivatives as hydrogen carrier

1. A method for producing hydrogen comprising the steps of:

i) contacting a compound (C) comprising one or more groups Si—H with a phosphorous based catalyst in the presence of a base in water as solvent, thereby forming hydrogen and a by-product (C1);

wherein said phosphorous based catalyst is selected from

a compound of formula X 1 X 2 X 3 P(═O) wherein:

X 1 , X 2 , X 3 are each, independently selected from C 1 -C 6 alkyl, C 1 -C 6 alkoxy, NR a R b , C 6 -C 10 aryl, aralkyl, 5 to 7 membered heteroaryl;

wherein said alkyl or aryl groups are optionally substituted by one to three R e ;

or

X 1 and X 2 together form with the phosphorous atom to which they are attached a 3 to 10 membered heterocycloalkyl optionally substituted by R d ; and X 3 is as defined above

or

X 3 is -L-P(═O)X 1 X 2 , wherein L is C 1 -C 6 alkylene or C 6 -C 10 arylene and X 1 , X 2 are as defined above; wherein:

R a and R b are each independently selected from C 1 -C 6 alkyl, C 6 -C 10 aryl or together form with the phosphorous atom to which they are attached a heterocyclyl optionally substituted by one to three R e ;

R c , R d and R e are each independently selected from Cl, Br, I, F, OH, C 1 -C 6 alkyl, C 1 -C 6 alkoxy, NO 2 , NH 2 , CN, COOH;

a polymer-supported catalyst bearing one or more groups R a R b (P═O)—, wherein R a and R b are each independently selected from C 1 -C 6 alkyl, C 6 -C 10 aryl or together form with the phosphorous atom to which they are attached a heterocyclyl optionally substituted by one to three R e ;

ii) recovering the obtained hydrogen.

2. The method of claim 1 , wherein one of X 1 , X 2 , X 3 is NR a R b .

3. The method of claim 1 , wherein R a and/or R b are C 1 -C 6 alkyl.

4. The method of claim 1 , wherein the phosphorous based catalyst is hexamethylphosphoramide (HMPA).

5. The method of claim 1 , wherein the polymer which supports the catalyst is (Aminomethyl)polystyrene.

6. The method of claim 1 , wherein the molar ratio of the phosphorous based catalyst relative to compound (C) ranges from 0.01 to 0.1 equivalents.

7. The method of claim 1 , wherein the compound (C) comprises one or more monomer units of formula (A):

wherein:

R is a bond, C 1 -C 6 alkylene, (C 1 -C 4 alkylene) m -Z—(C 1 -C 4 alkylene) q ;

Z is O, NR 10 , S(O) y , CR 10 ═CR 10 , C≡C, C 6 -C 10 arylene, 5-10 membered heteroarylene, or C 3 -C 6 cycloalkylene;

R 1 , R 2 are each independently selected from H, halogen, C 1 -C 10 alkyl, C 3 -C 10 cycloalkyl, C 6 -C 12 aryl, aralkyl, 5 to 10-membered heteroaryl, OR 3 , NR 4 R 5 , SiR 6 R 7 R 8 , wherein said aryl groups are optionally substituted by one to three R 9 groups;

R 3 is H, C 1 -C 6 alkyl, C 6 -C 10 aryl, aralkyl;

R 4 , R 5 are each independently selected from H, C 1 -C 6 alkyl, C 6 -C 10 aryl, aralkyl;

R 6 , R 7 , R 8 are each independently selected from H, OR 3 , C 1 -C 6 alkyl, C 6 -C 10 aryl, aralkyl;

R 9 is selected from halogen, C 1 -C 10 alkyl, OR 10 , NO 2 , NR 11 R 12 , CN, C(═O)R 10 , C(═O)OR 10 , S(═O)CH 3 , wherein said alkyl group is optionally substituted by one or more halogen;

R 10 is H or C 1 -C 3 alkyl;

R 11 , R 12 are each independently selected from H, or C 1 -C 10 alkyl;

m, q are 0 or 1;

y is 0, 1 or 2;

n, p are integers each representing the number of repeating units, with

n being superior or equal than 1, and

p being 0 or 1.

8. The method of claim 7 , wherein p is 0.

9. The method of claim 8 , wherein the compound (C) comprising a monomer unit of formula (Ia) is PhSiH 3 .

10. The method of claim 1 , wherein the compound (C) comprises a monomer unit of formula C(SiH 3 ) 4 .

11. The method of claim 7 , wherein p is 1.

12. The method of claim 11 , wherein the monomer unit is of formula (Ib):

wherein R is C 1 -C 6 alkylene.

13. The method of claim 12 , wherein the compound (C) comprising a monomer unit of formula (Ib) is H 3 Si(CH 2 ) 2 SiH 3 .

14. The method of claim 1 , wherein the base is an alkaline or alkaline earth metal hydroxide, or benzylamine.

15. The method of claim 1 , further comprising the following subsequent recycling steps:

a) contacting the by-product (C1) with an acyl halide;

b) contacting the obtained product with a metal hydride, thereby regenerating compound (C).

16. A composition comprising a compound that comprises one or more groups Si—H, a phosphorus based catalyst, a base and water as solvent,

wherein said phosphorous based catalyst is selected from:

a compound of formula X 1 X 2 X 3 P(═O) wherein:

X 1 , X 2 , X 3 are each, independently selected from C 1 -C 6 alkyl, C 1 -C 6 alkoxy, NR a R b , C 6 -C 10 aryl, aralkyl, 5 to 7 membered heteroaryl;

wherein said alkyl or aryl groups are optionally substituted by one to three R c ; or

X 1 and X 2 together form with the phosphorous atom to which they are attached a 3 to 10 membered heterocycloalkyl optionally substituted by R d ; and X 3 is as defined above

or

X 3 is -L-P(═O)X 1 X 2 , wherein L is C 1 -C 6 alkylene or C 6 -C 10 arylene and X 1 , X 2 are as defined above ;

R a and R b are each independently selected from C 1 -C 6 alkyl, C 6 -C 10 aryl or together form with the phosphorous atom to which they are attached a heterocyclyl optionally substituted by one to three

R e ;

R c , R d and R e are each independently selected from Cl, Br, I, F, OH, C 1 -C 6 alkyl, C 1 -C 6 alkoxy, NO 2 , NH 2 , CN, COOH;

a polymer-supported catalyst bearing one or more groups R a R b (P═O)—, wherein R a and R b are each independently selected from C 1 -C 6 alkyl, C 6 -C 10 aryl or together form with the phosphorous atom to which they are attached a heterocyclyl optionally substituted by one to three R e .

17. A device for producing hydrogen according to the method of claim 1 , said device comprising a reaction chamber comprising:

i. A reaction mixture inlet, said mixture comprising a compound (C), a base in water as a solvent;

ii. an hydrogen outlet;

iii. a by-product collector; and

iv. a surface intended to be in contact with said mixture, coated with a polymer supported catalyst selected from:

a compound of formula X 1 X 2 X 3 P(═O) wherein:

X 1 , X 2 , X 3 are each, independently selected from C 1 -C 6 alkyl, C 1 -C 6 alkoxy, NR a R b , C 6 -C 10 aryl, aralkyl, 5 to 7 membered heteroaryl;

wherein said alkyl or aryl groups are optionally substituted by one to three R c ; or

X 1 and X 2 together form with the phosphorous atom to which they are attached a 3 to 10 membered heterocycloalkyl optionally substituted by R d ; and X 3 is as defined above

or

X 3 is -L-P(═O) X 1 X 2 , wherein L is C 1 -C 6 alkylene or C 6 -C 10 arylene and X 1 , X 2 are as defined above;

R a and R b are each independently selected from C 1 -C 6 alkyl, C 6 -C 10 aryl or together form with the phosphorous atom to which they are attached a heterocyclyl optionally substituted by one to three R e ;

R c , R d and Re are each independently selected from Cl, Br, I, F, OH, C 1 -C 6 alkyl, C 1 -C 6 alkoxy, NO 2 , NH 2 , CN, COOH;

a polymer-supported catalyst bearing one or more groups R a R b (P═O)—, wherein R a and R b are each independently selected from C 1 -C 6 alkyl, C 6 -C 10 aryl or together form with the phosphorous atom to which they are attached a heterocyclyl optionally substituted by one to three R e .

18. The device of claim 17 , further comprising a mixing chamber for mixing the compound (C) with the base in water as a solvent, wherein the mixing chamber is connected to the reaction chamber.

19. The device of claim 17 further comprising a by-product collection chamber, wherein the collection chamber is connected to the reaction chamber.

20. The device of claim 17 , further comprising a second chamber comprising:

v. an outer envelope;

vi. an internal wall separating said chamber into two distinct compartments, namely:

1. a first compartment containing the reaction mixture to be introduced in the reaction chamber; and

2. a second compartment containing the by-product (C1) collected from the reaction chamber;

3. the first and second compartment being each connected to the reaction chamber;

and

vii. means for moving the internal wall relative to the outer envelope, so as to make the respective volumes of each compartment to vary.