Process for the production of hypophosphite salts

Abstract

Disclosed is a process to produce a hypophosphite salt defined as [C.sup.+ hypophosphite.sup.] by reacting P4 with a hydroxide salt defined as [C.sup.+OH.sup.], or a hydroxide salt precursor and a catalyst, wherein C.sup.+ is the cationic moiety of [C.sup.+ hypophosphite.sup.] salt.

Claims

1. A process to produce a hypophosphite salt defined as [C.sup.+ Hypophosphite.sup.] by reacting P.sub.4 with a hydroxide salt, defined as [C.sup.+OH.sup.], or a hydroxide salt precursor; and a quaternary ammonium salt or a phosphonium salt; wherein C.sup.+ is the cationic moiety of [C.sup.+ Hypophosphite.sup.] salt.

2. The process according to claim 1, wherein said process permits to the production of a hypophosphite salt and a phosphite salt with a molar ratio of said hypophosphite salt/said phosphite salt greater than 1.5.

3. The process according to claim 1, wherein the quaternary ammonium salt is a quaternary ammonium salt of formula (I): ##STR00004## wherein: R.sup.1, R.sup.2, R.sup.3 and R.sup.4 independently of one another represent an organic hydrocarbon group, and X is an organic or an inorganic anion.

4. The process according to claim 3, wherein R.sup.1, R.sup.2, R.sup.3 and R.sup.4 independently of one another represent a branched or unbranched alkyl group having 1-18 carbon atoms.

5. The process according to claim 3, wherein X is an organic or an inorganic anion that is OH, a halogen atom, a sulfate, a carbonate or an alkylate.

6. The process according to claim 3, wherein compounds of formula (I) are selected from the group consisting of tetrabutylammonium hydroxide, tetrabutylammonium chroride, tetrabutylammonium bromide, benzalkonium chloride, tetraethylammonium hydroxide, tetramethylammonium chloride, tetramethylammonium hydroxide, tetraethylammonium bromide, cetrimonium bromide, dimethyldioctadecylammonium chloride, benzyltrimethylammonium chloride, benzyltrimethylammonium bromide, tetrabutylammonium acetate, and tetrapropylammonium hydroxide.

7. The process according to claim 1, wherein the molar proportions of quaternary ammonium salt or a phosphonium salt is between 0.1 and 40%, in relation with the mol of P.sub.4.

8. The process according to claim 1, wherein the molar proportions of quaternary ammonium salt is between 10 and 40%, in relation with the mol of P.sub.4.

9. The process according to claim 1, wherein C.sup.+ is the cationic moiety of [C.sup.+ Hypophosphite.sup.] salt that represents a metal, an alkali earth metal, an alkali metal or a quaternary ammonium or quaternary phosphonium.

10. The process according to claim 1, wherein said [C.sup.+OH.sup.] is a quaternary ammonium salt or a phosphonium salt.

11. The process according to claim 10 wherein [C.sup.+OH.sup.] is a quaternary ammonium salt of formula (I): ##STR00005## wherein: R.sup.1, R.sup.2, R.sup.3 and R.sup.4 independently of one another represent an organic hydrocarbon group, and X is OH.sup..

12. The process according to claim 1, wherein the molar ratio [C.sup.+OH.sup.]/P.sub.4 is comprised between 0.5 and 4.

13. The process according to claim 1, wherein the hypophosphite salt is a compound of the formula (II) as defined below:
[H2-P(O)O.sup.].sub.nC.sup.n+(II) wherein: n is comprised between 1 and 5; and C is a cation.

14. The process according to claim 1, wherein said reaction occurs at a temperature between 50 and 150 C.

15. The process according to claim 1, wherein said pH of the reaction is greater than 7.

Description

EXPERIMENTAL PART

Example 1: Bu4NOH as Catalyst

(1) Equimolar proportions of P.sub.4, Ca(OH).sub.2 and H.sub.2O are reacted with different loading of Bu.sub.4NOH (% mol in relation with mol of the P.sub.4).

(2) ##STR00002##

(3) A flask was equipped with cooling condenser and magnetic stir under a flow of argon and the out gas was collected by a gas bag. Under argon protection, this flask was charged with 1.52 g (0.049 mol) P4 and 1.93 g H.sub.2O. Then 4.92 g (0.066 mol) Ca(OH).sub.2 and 19.12 g (0.007 mol) Bu.sub.4NOH (10% water solution) were added into and the resulting mixture was heated to 95 C. for 4 h with generated phosphine collection by gas bag. When reaction was completed, reaction mixture was cooled down. After using concentrated HCl to dissolve all solid, 0.4 g H.sub.3PO.sub.4 (85%) was added as internal standard of P-NMR. P-NMR analysis showed this mixture contained 33.9% hypophosphite and 19.2% phosphate with ratio of 1.8

(4) P-NMR (300 MHz, D.sub.2O, decoupling): 11.98 (hypophosphite), 4.52 (phosphite), 0.414 (phosphate)

(5) A flask was equipped with cooling condenser and magnetic stir under a flow of argon and the out gas was collected by a gas bag. Under argon protection, this flask was charged with 1.52 g (0.049 mol) P4 and 3.82 g H.sub.2O. Then 4.31 g (0.058 mol) Ca(OH).sub.2 and 37.7 g (0.015 mol) Bu.sub.4NOH (10% water solution) were added into and the resulting mixture was heated to 95 C. for 4 h with generated phosphine collection by gas bag. When reaction was completed, reaction mixture was cooled down. After using concentrated HCl to dissolve all solid, 0.4 g H.sub.3PO.sub.4 (85%) was added as internal standard of P-NMR. P-NMR analysis showed this mixture contained 38.4% hypophosphite and 18.5% phosphate with ratio of 2.1

(6) P-NMR (300 MHz, D.sub.2O, decoupling): 11.98 (hypophosphite), 4.52 (phosphite), 0.414 (phosphate)

(7) Results are expressed in Table 1

(8) TABLE-US-00001 TABLE 1 Catalyst (mol %) Hyphosphite/Phoshite ratio 0 1.5 15 1.8 30 2.0

(9) It appears then that the use of a catalyst in the reaction permits to increase the Hyphosphite/Phoshite ratio.

Example 2: Bu4NOH as Catalyst and as Reactant

(10) Some proportions of P.sub.4, Bu.sub.4NOH and H.sub.2O are reacted with Bu.sub.4NOH as catalyst

(11) ##STR00003##

(12) A flask was equipped with cooling condenser and magnetic stir under a flow of argon and the out gas was collected by a gas bag. Under argon protection, this flask was charged with 0.15 g (0.005 mol) P4 and 42.9 g H2O. Then 1.88 g (0.007 mol) Bu.sub.4NOH (10% water solution) was added into and the resulting mixture was heated to 95 C. for 4 h with generated phosphine collection by gas bag. When reaction was completed, reaction mixture was cooled down. After using concentrated HCl to dissolve all solid, 0.4 g H.sub.3PO.sub.4 (85%) was added as internal standard of P-NMR. P-NMR analysis showed this mixture contained 43.5% hypophosphite and 18.9% phosphate with ratio of 2.3

(13) P-NMR (300 MHz, D.sub.2O, decoupling): 11.98 (hypophosphite), 4.52 (phosphite), 0.414 (phosphate)

(14) A flask was equipped with cooling condenser and magnetic stir under a flow of argon and the out gas was collected by a gas bag. Under argon protection, this flask was charged with 0.66 g (0.021 mol) P4 and 30.4 g H2O. Then 3.38 g (0.013 mol) Bu.sub.4NOH (10% water solution) was added into and the resulting mixture was heated to 95 C. for 4 h with generated phosphine collection by gas bag. When reaction was completed, reaction mixture was cooled down. After using concentrated HCl to dissolve all solid, 0.4 g H.sub.3PO.sub.4 (85%) was added as internal standard of P-NMR. P-NMR analysis showed this mixture contained 22.6% hypophosphite and 9.3% phosphate with ratio of 2.43

(15) P-NMR (300 MHz, D.sub.2O, decoupling): 11.98 (hypophosphite), 4.52 (phosphite), 0.414 (phosphate)

(16) A flask was equipped with cooling condenser and magnetic stir under a flow of argon and the out gas was collected by a gas bag. Under argon protection, this flask was charged with 0.38 g (0.012 mol) P4 and 9.43 g H.sub.2O. Then 4.9 g (0.019 mol) Bu.sub.4NOH (10% water solution) was added into and the resulting mixture was heated to 95 C. for 4 h with generated phosphine collection by gas bag. When reaction was completed, reaction mixture was cooled down. After using concentrated HCl to dissolve all solid, 0.4 g H.sub.3PO.sub.4 (85%) was added as internal standard of P-NMR.

(17) P-NMR analysis showed this mixture contained 34.1% hypophosphite and 11.8% phosphate with ratio of 2.89

(18) P-NMR (300 MHz, D.sub.2O, decoupling): 11.98 (hypophosphite), 4.52 (phosphite), 0.414 (phosphate)

(19) Results are expressed in Table 2.

(20) TABLE-US-00002 TABLE 2 P4 Bu.sub.4NOH H.sub.2O Bu.sub.4NOH/ Bu.sub.4NOH/ Hypophophite Hyphosphite/Phoshite (mol) (mol) (mol) P.sub.4 H.sub.2O (%) Conversion Ratio 0.005 0.007 2.381 1.400 0.003 43.5 62.4 2.30 0.021 0.013 1.688 0.619 0.008 22.6 31.9 2.43 0.012 0.019 0.523 1.583 0.036 34.1 45.9 2.89

(21) It appears then that the use of a compound as a hydroxide salt and a catalyst in the reaction permits to increase the Hyphosphite/Phoshite ratio.