Disclosed herein are compounds of the general Formula (I), and methods of synthesizing a substituted bicyclo[1.1.1]pentane using a Group VII or Group IX transition metal compound.

The present invention relates to a polyisocyanate composition comprising, on the basis of the total mass of the polyisocyanate composition, 97 weight % or more of a polyisocyanate, and 2.0 mass ppm or more and 1.010.sup.4 mass ppm or less of a compound having at least one unsaturated bond in which the compound is a different compound from the polyisocyanate, or 5.0 mass ppm or more and 2.010.sup.4 mass ppm or less of at least one inactive compound selected from the group consisting of a hydrocarbon compound, an ether compound, a sulfide compound, a halogenated hydrocarbon compound, a Si-containing hydrocarbon compound, a Si-containing ether compound, and a Si-containing sulfide compound.

Disclosed is a preparation method for a low-color number, low-odor polyisocyanate curing agent. The preparation method comprises a step of carrying out a polymerization reaction on a diisocyanate monomer under the action of a trimerization catalyst in a polymerization reaction kettle with continuously flowing inert gas, an upper head of the polymerization reaction kettle being provided with an inert gas inlet pipe, the inert gas inlet pipe being an insertion pipe, and the upper head of the polymerization reaction kettle also being provided with an inert gas outlet and a central stirring shaft; the insertion opening position (A) of the inert gas inlet pipe and the inert gas outlet position (B) on the surface of the upper head form an angle (ACB) with the fixed position (C) of the central stirring shaft projected onto the plane on the upper head surface, where 30180. The present application can achieve stable catalytic activity of a catalyst by means of controlling the use of nitrogen during the reaction process, which is conducive to stable process control, resulting in a low color number and reduced amine odor in the obtained product.