Crystalline form of phenyl bis (2,4,6-trimethylbenzoyl) phosphine oxide with large particle size and crystallization method for making same

1. A crystalline form of bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide with a large particle size, having:

an X-ray powder diffraction pattern comprising characteristic peaks at 4.7±0.1, 9.3±0.1, 12.2±0.1, 13.5±0.1, 14.0±0.1, 16.2±0.1, 17.3±0.1, 18.7±0.1, 19.6±0.1, and 24.9±0.1 degrees 2θ; wherein, the crystalline form belongs to a triclinic crystal system and to a space group P-1;

and wherein, the crystalline form is characterized by unit cell parameters equal to the following:

cell dimensions from single crystal:

a=8.0301(16)Å

b=8.6673(17)Å

c=19.252(4)Å

α=84.07(3°)

β=82.83(3°)

γ=63.75(3°)

molecules/unit cell (Z): 2.

2. The crystalline form of claim 1 , having:

a melting point measured by differential scanning calorimetry of 117° C. to 121° C.; and

a thermo-gravimetric analysis profile showing that the crystalline form starts to lose weight at 110±1° C. with a weight loss of 6.9±0.1% and starts to decompose and thus lose weight at 160±1° C.

3. A crystallization method for making the crystalline form of bis(2,4,6-trimethylbenzoyl) phenylphosphine oxide with a large particle size according to claim 1 , comprising steps of:

(1) adding a solid of bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide to a solvent and mixing with stirring, followed by heating to 50 to 70° C. to achieve complete dissolution and cooling the solution to room temperature; and

(2) adding an anti-solvent to the solution obtained in the step (1) to cause precipitation of crystals and allowing the crystals to grow at a constant temperature for 10 to 60 minutes, so as to give a slurry containing the crystals, which is subjected to filtration and then drying to obtain a crystal product of bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide.

4. The method of claim 3 , wherein the ratio of the solid bis(2,4,6-trimethylbenzoyl) phenylphosphine oxide to the solvent in the step (1) is 0.125 to 0.159 g/mL.

5. The method of claim 3 , wherein the solvent used in the step (1) is a ketone, an ester, or a mixture thereof, wherein the ketone is selected from acetone, 2-butanone, cyclohexanone, and methyl isobutyl ketone, and wherein the ester is selected from methyl acetate, ethyl acetate, ethyl n-valerate, ethyl propionate, and n-butyl acetate.

6. The method of claim 3 , wherein the stirring is carried out with a stirring speed of 50 to 300 rpm.

7. The method of claim 3 , wherein the anti-solvent is an alcohol, an alkane, or a mixture thereof,

wherein the alcohol is selected from methanol, ethanol, isopropanol, ethylene glycol, and glycerol, and wherein the alkane is selected from n-heptane, cyclopentane, n-hexane, and petroleum ether.

8. The method of claim 3 , wherein the anti-solvent is used in an amount of 0.4 to 3 times by volume the amount of the solvent used in the step (1), and is added to the solution obtained in the step (1) at a rate of 0.2 to 45% by volume with respect to the total volume of the anti-solvent per minute.

9. The method of claim 3 , wherein the drying is carried out under vacuum at 50° C. to 60° C. until constant weight is reached.

10. A crystalline form of bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide with large particle size, having:

an X-ray powder diffraction pattern comprising characteristic peaks at 4.7±0.1, 9.3±0.1, 12.2±0.1, 13.5±0.1, 14.0±0.1, 16.2±0.1, 17.3±0.1, 18.7±0.1, 19.6±0.1, and 24.9±0.1 degrees 2θ; wherein, the crystalline form belongs to a triclinic crystal system and to a space group P-1;

and wherein, the crystalline form is characterized by unit cell parameters substantially equal to the following:

cell dimensions from single crystal:

a=8.0301(16)Å

b=8.6673(17)Å

c=19.252(4)Å

α=84.07(3°)

β=82.83(3°)

γ=63.75(3°)

molecules/unit cell (Z): 2;

wherein the crystalline form of bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide is fabricated in accordance with the steps:

(1) adding a solid of bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide to a solvent and mixing with stirring, followed by heating to 50 to 70° C. to achieve complete dissolution and cooling the solution to room temperature; and

(2) adding an anti-solvent to the solution obtained in the step (1) to cause precipitation of crystals and allowing the crystals to grow at a constant temperature for 10 to 60 minutes, so as to give a slurry containing the crystals, which is subjected to filtration and then drying to obtain a crystal product of bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide.

11. The crystalline form of claim 10 , having:

a melting point measured by differential scanning calorimetry of 117 to 121° C.; and

a thermo-gravimetric analysis profile showing that the crystalline form starts to lose weight at 110±1° C. with a weight loss of 6.9±0.1% and starts to decompose and thus lose weight at 160±1° C.

12. The crystalline form of claim 11 , wherein the ratio of the solid bis(2,4,6-trimethylbenzoyl) phenylphosphine oxide to the solvent in the step (1) is 0.125 to 0.159 g/mL.

13. The crystalline form of claim 11 , wherein:

the anti-solvent is an alcohol, an alkane, or a mixture thereof,

the alcohol is selected from methanol, ethanol, isopropanol, ethylene glycol, and glycerol, and

the alkane is selected from n-heptane, cyclopentane, n-hexane, and petroleum ether.