Abstract: The invention relates to a process for the preparation of aliphatic, cycloaliphatic or araliphatic isocyanates by reacting at least one primary organic amine with a stoichiometric excess of phosgene in the gas phase, comprising the steps a) reaction of the primary organic amine with an excess of phosgene in the gas phase and quenching the process product with a liquid comprising an inert aromatic solvent to obtain a liquid stream containing the isocyanate and a gas stream containing HCl and phosgene, b) separation of the gas stream containing HCl and phosgene obtained in step a) into a gas stream containing HCl and a liquid stream containing phosgene, c) partial vaporization of the liquid stream containing phosgene obtained in step b) to produce a gas stream containing phosgene, d) the gas stream containing phosgene obtained in step c) is at least partially recycled into the reaction in step a), and wherein the gas stream containing phosgene obtained in step c) contains 0.

Abstract: The present invention provides a new type of filtration system. Traditional designs required that personnel open the system to clean/change strainers while a process was in operation. This invention provides a straining system that allows process stream to be filtered in a manner completely internal to the process. The system includes dual strainers with a nitrogen purging system and solvent flush system. A creatively designed “catch” area is installed internal to the process to collect all solids that are flushed from the strainer system. The system remains completely closed for the duration of each production campaign, thus eliminating the safety hazard and labor requirement associated with opening a process system.

Abstract: A method and a continuous process for producing two isocyanates by reacting a first amine with phosgene in a stoichiometric excess in the gas phase to produce a first isocyanate. The excess phosgene is subsequently recovered and recirculated back to react with a second amine to produce a second isocyanate. In an embodiment, both fresh and recycled phosgene may be used in reacting each respective amine to produce an isocyanate. The amine streams contain two different concentrations of hydrogen chloride: one may be between 0.0 and 0.1%, and another may be between 1 and 5% by weight.

Abstract: The invention relates to a method for producing two isocyanates by reacting a first amine with phosgene in a stoichiometric excess in the gas phase to produce a first isocyanate, wherein the excess phosgene is subsequently recovered and recirculated back to react with a second amine to produce a second isocyanate. In another embodiment, both fresh and recycled phosgene may be used in reacting each respective amine to produce an isocyanate. The amine streams may be optimized to contain different concentrations of hydrogen chloride, as required for the production of two different isocyanates.

Abstract: The present invention provides a new type of filtration system. Traditional designs required that personnel open the system to clean/change strainers while a process was in operation. This invention provides a straining system that allows process stream to be filtered in a manner completely internal to the process. The system includes dual strainers with a nitrogen purging system and solvent flush system. A creatively designed “catch” area is installed internal to the process to collect all solids that are flushed from the strainer system. The system remains completely closed for the duration of each production campaign, thus eliminating the safety hazard and labor requirement associated with opening a process system.