The invention relates to a process for the preparation of Efavirenz via an efficient transition metal catalyzed cyclization, to a device suitable to perform such process as well as to novel intermediates.

The invention relates to a process for preparing isocyanates by reacting primary amines with phosgene in a solvent, where the solvent comprises a dialkyl carbonate.

The invention relates to a process for preparing isocyanates by reacting primary amines with phosgene in a solvent, where the solvent comprises a dialkyl carbonate.

A process for preparing an aromatic isocyanate by direct carbonylation of a nitro aromatic compound by reacting the nitro aromatic compound with carbon monoxide in the presence of a catalyst, characterized in that the catalyst contains a multi metallic material comprising one or more binary intermetallic phases of the general formula A.sub.xB.sub.y wherein: A is one or more element selected from Ni, Ru, Rh, Pd, Ir, Pt and Ag, B is one or more element selected from Sn, Sb, Pb, Zn, Ga, In, Ge and As, x is in the range 0.1-10, y in is in the range 0.1-10.

A process for preparing an aromatic isocyanate by direct carbonylation of a nitro aromatic compound by reacting the nitro aromatic compound with carbon monoxide in the presence of a catalyst, characterized in that the catalyst contains a multi metallic material comprising one or more binary intermetallic phases of the general formula A.sub.xB.sub.y wherein: A is one or more element selected from Ni, Ru, Rh, Pd, Ir, Pt and Ag, B is one or more element selected from Sn, Sb, Pb, Zn, Ga, In, Ge and As, x is in the range 0.1-10, y in is in the range 0.1-10.

Disclosed in the present invention are an isocyanate composition, a modified composition, and a polyurethane elastomer, the isocyanate composition having an effective factor of 3.80-5.30. By means of designing and controlling the effective factor, the isocyanate composition has excellent reaction activity and thus can be used for preparing high-performance polyurethane products. The isocyanate composition can improve stability of polyurethane products, and particularly, can remarkably improve resistance to color changes and weather resistance of polyurethane elastomers, suppress increases of color codes and yellowing under humid and hot conditions, and improve the tensile strength and tearing strength of polyurethane elastomers, such that the polyurethane elastomers have excellent comprehensive performance in the areas such as weather resistance, stability and mechanical properties.

Disclosed in the present invention are an isocyanate composition, a modified composition, and a polyurethane elastomer, the isocyanate composition having an effective factor of 3.80-5.30. By means of designing and controlling the effective factor, the isocyanate composition has excellent reaction activity and thus can be used for preparing high-performance polyurethane products. The isocyanate composition can improve stability of polyurethane products, and particularly, can remarkably improve resistance to color changes and weather resistance of polyurethane elastomers, suppress increases of color codes and yellowing under humid and hot conditions, and improve the tensile strength and tearing strength of polyurethane elastomers, such that the polyurethane elastomers have excellent comprehensive performance in the areas such as weather resistance, stability and mechanical properties.

The present invention relates to a process for preparing a polyisocyanate, namely an isocyanate group-terminated polyol polyanthranilic acid ester. The process comprises the step of reacting an anthranilic acid derivative selected from anthranilic acid halide (in particular anthranilic acid chloride), isatoic anhydride or a mixture thereof with a first polyol of a number-average molar mass of at least 200 g/mol and a functionality in the range of 2 to 8, and obtaining, as a result, a polyamine (namely a polyol polyanthranilic acid ester with amine terminal groups) and reacting the polyamine with phosgene and obtaining, as a result, a polyisocyanate (namely an isocyanate group-terminated polyol polyanthranilic acid ester). The invention further relates to the polyisocyanates obtained in this way, their use in polyaddition reactions, and polyaddition products obtainable by these reactions.

The present invention relates to a process for preparing a polyisocyanate, namely an isocyanate group-terminated polyol polyanthranilic acid ester. The process comprises the step of reacting an anthranilic acid derivative selected from anthranilic acid halide (in particular anthranilic acid chloride), isatoic anhydride or a mixture thereof with a first polyol of a number-average molar mass of at least 200 g/mol and a functionality in the range of 2 to 8, and obtaining, as a result, a polyamine (namely a polyol polyanthranilic acid ester with amine terminal groups) and reacting the polyamine with phosgene and obtaining, as a result, a polyisocyanate (namely an isocyanate group-terminated polyol polyanthranilic acid ester). The invention further relates to the polyisocyanates obtained in this way, their use in polyaddition reactions, and polyaddition products obtainable by these reactions.

A xylylene diisocyanate (XDI) composition according to exemplary embodiments includes xylylene diisocyanate and an acidity regulator having a boiling point of 110 C. or higher, and the composition has an acidity of greater than 100 ppm and 1,000 ppm or less based on a total weight of the xylylene diisocyanate (XDI). An optical lens having a high transmittance and improved optical uniformity can be manufactured by controlling a polymerization reaction rate through acidity adjustment.