Silyl phosphine compound, process for producing silyl phosphine compound and process for producing InP quantum dots

A process for producing a composition comprising a silyl phosphine compound represented by the following formula (1), wherein an arsenic content is not more than 1 ppm by mass,

• wherein each R is independently an alkyl group having not less than 1 and not more than 5 carbon atoms or an aryl group having not less than 6 and not more than 10 carbon atoms,
• wherein a content of at least one of compounds represented by the following formulas (2) to (7) as a ratio to a content of the compound represented by the formula (1) in the composition satisfies a corresponding one of the following requirements (a) to (f):
• (a) the content of the compound represented by the following formula (2) is not more than 0.3 mol %,
• wherein R is the same as in the formula (1),
• (b) the content of the compound represented by the following formula (3) is not more than 0.1 mol %,
• wherein R is the same as in the formula (1),
• (c) the content of the compound represented by the following formula (4) is not more than 0.50 mol %,
• wherein R is the same as in the formula (1),
• (d) the content of the compound represented by the following formula (5) is not more than 0.30 mol %,
• wherein R is the same as in the formula (1),
• (e) the content of the compound represented by the following formula (6) is not more than 0.30 mol %,
• wherein R is the same as in the formula (1);
• and
• (f) the content of the compound represented by the following formula (7) is not more than 1.0 mol %,
• wherein R is the same as in the formula (1),
• the method comprising:
• a first step of mixing a solvent which contains no halogen atom, a basic compound, a silylating agent represented by the following formula (I) and phosphine to obtain a solution containing a silyl phosphine compound;
• a second step of removing the solvent from the solution containing a silyl phosphine compound to obtain a concentrated solution of a silyl phosphine compound under a reduced pressure of not less than 5 kPa and not more than 20 kPa in terms of absolute pressure;
• and
• a third step of distilling the concentrated solution of a silyl phosphine compound to obtain the silyl phosphine compound under a reduced pressure of not less than 0.01 kPa and not more than 4 kPa in terms of absolute pressure;
• wherein as the phosphine, phosphine having an arsenic content of not more than 1 ppm by volume in terms of arsine is used,
• wherein each R is independently an alkyl group having not less than 1 and not more than 5 carbon atoms or an aryl group having not less than 6 and not more than 10 carbon atoms, and X is at least one group selected from a fluorosulfonic acid group, a fluoroalkanesulfonic acid group and a perchloric acid group.