Disclosed is to prevent generation of byproducts or a deterioration in the physical properties of a polythiol composition that may be caused by active oxygen during storage thereof by way of controlling the content of active oxygen in the polythiol composition after the synthesis of the polythiol. As a result, it is possible to enhance the long-term storage stability of a polythiol composition after it has been synthesized until it is used in the polymerization reaction.

Disclosed is to prevent generation of byproducts or a deterioration in the physical properties of a polythiol composition that may be caused by active oxygen during storage thereof by way of controlling the content of active oxygen in the polythiol composition after the synthesis of the polythiol. As a result, it is possible to enhance the long-term storage stability of a polythiol composition after it has been synthesized until it is used in the polymerization reaction.

Disclosed is to prevent generation of byproducts or a deterioration in the physical properties of a polythiol composition that may be caused by active oxygen during storage thereof by way of controlling the content of active oxygen in the polythiol composition after the synthesis of the polythiol. As a result, it is possible to enhance the long-term storage stability of a polythiol composition after it has been synthesized until it is used in the polymerization reaction.

Provided is a preparation of a thioether-based polythiol in a high purity using a metal monosulfide for the incorporation of a thioether group, wherein the content of such components as a metal polysulfide present in the metal monosulfide is controlled to a predetermined level or lower. As a result, an optical lens of high quality with a high refractive index can be produced using the polythiol.

Provided is a preparation of a thioether-based polythiol in a high purity using a metal monosulfide for the incorporation of a thioether group, wherein the content of such components as a metal polysulfide present in the metal monosulfide is controlled to a predetermined level or lower. As a result, an optical lens of high quality with a high refractive index can be produced using the polythiol.

A photosensitive composition which tends to hardly occur excessive decrease of weight of a component (in which is a component other than a solvent, when the composition or the photosensitive composition includes the solvent) in the composition or the photosensitive composition by heating, and include inorganic microparticles in a stably dispersed state, a cured product of the photosensitive composition, a compound which can be preferably added to the composition and the photosensitive composition, and a production method of the compound are provided. In a composition including a photopolymerizable compound (A) and inorganic microparticles (B) or a photosensitive composition including a photopolymerizable compound (A), inorganic microparticles (B), and an initiator, a compound with a specific structure having a radically polymerizable group-containing group or a cationically polymerizable group-containing group is used as the photopolymerizable compound (A).

Provided are: A collector containing a compound that increases the recovery amount of a target mineral; a flotation method that uses this compound; and a compound that is suitable as a collector. This collector includes a compound represented by the following formula (1).

##STR00001##

(In formula (1), R.sup.1 represents an alkyl group having 1 or more and 18 or less carbon atoms, and X represents NR.sup.2R.sup.3, SR.sup.4, or OR.sup.5, and R.sup.2-3 each represents hydrogen or an alkyl group having 1 or more and 18 or less carbon atoms, and R.sup.4-5 each represent an alkyl group having 1 or more and 18 or less carbon atoms.

The present disclosure features a strain-promoted [2+2+2] reaction that can be carried out under physiological conditions. In general, the reaction involves reacting a pi-electrophile with a low lying LUMO with a quadricyclane on a biomolecule, generating a covalently modified biomolecule. The selectivity of the reaction and its compatibility with aqueous environments provides for its application in vivo and in vitro. The reaction is compatible with modification of living cells. In certain embodiments, the pi-electrophile can comprise a molecule of interest that is desired for delivery to a quadricyclane-containing biomolecule via [2+2+2] reaction.

The present disclosure features a strain-promoted [2+2+2] reaction that can be carried out under physiological conditions. In general, the reaction involves reacting a pi-electrophile with a low lying LUMO with a quadricyclane on a biomolecule, generating a covalently modified biomolecule. The selectivity of the reaction and its compatibility with aqueous environments provides for its application in vivo and in vitro. The reaction is compatible with modification of living cells. In certain embodiments, the pi-electrophile can comprise a molecule of interest that is desired for delivery to a quadricyclane-containing biomolecule via [2+2+2] reaction.

The present disclosure features a strain-promoted [2+2+2] reaction that can be carried out under physiological conditions. In general, the reaction involves reacting a pi-electrophile with a low lying LUMO with a quadricyclane on a biomolecule, generating a covalently modified biomolecule. The selectivity of the reaction and its compatibility with aqueous environments provides for its application in vivo and in vitro. The reaction is compatible with modification of living cells. In certain embodiments, the pi-electrophile can comprise a molecule of interest that is desired for delivery to a quadricyclane-containing biomolecule via [2+2+2] reaction.