Photochemical dimerization of organic compounds
AssigneeYale University
InventorsRobert H. Crabtree, Stephen H. Brown, Cesar A. Muedas, Richard R. Ferguson
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Abstract
At least one of selectivity and reaction rate of photosensitized vapor phase dimerizations, including dehydrodimerizations, hydrodimerizations and cross-dimerizations of saturated and unsaturated organic compounds is improved by conducting the dimerization in the presence of hydrogen or nitrous oxide.
Claims23
In a Group IIb photosensitized vapor phase dimerization of an organic compound in which a gaseous mixture of a Group IIB metal and the organic compound is irradiated in a reaction zone with a photosensitizing amount of radiant energy, the improvement wherein:
- (i) a continuous stream of the gaseous mixture is passed as a vapor phase in a single pass through the reaction zone at a temperature at which the thus-produced dimer condenses immediately upon the formation thereof and remains condensed while exposed to the radiant energy and both the condensate and a residual vapor phase are concurrently removed from the reaction zone, thereby minimizing secondary reactions between the dimer and itself, the starting organic compound or any by-products of the dimerization reaction, and the starting gaseous mixture comprises an actuating amount of hydrogen and the organic compound is an ethylenically unsaturated compound selected from the group consisting of unsaturated nitriles, unsaturated esters, unsaturated ethers, unsaturated ketones, unsaturated epoxides, unsaturated silanes, unsaturated amines, unsaturated phosphines and fluorinated alkenes;
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- (ii) the starting gaseous mixture comprises hydrogen and two ethylenically unsaturated compounds selected from the group consisting of alkenes of at least six carbon atoms, unsaturated nitriles, unsaturated epoxides, unsaturated silanes, unsaturated amines, unsaturated phosphines, and fluorinated alkenes and a continuous stream of the gaseous mixture is passed in a single pass through the reaction zone at a temperature at which the thus-produced dimer condenses immediately upon the formation thereof and remains condensed while exposed to the radiant energy and residual vapor phase is concurrently removed from the reaction zone, thereby minimizing secondary reactions between the dimer and itself, the starting organic compound or any by-products of the dimerization reaction;
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- (iii) the gaseous mixture comprises nitrous oxide and the organic compound is a saturated compound with C--H bond strengths greater than 100 kcal/mol or a mixture of the saturated compound and an alkene;
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- (iv) the starting gaseous mixture comprises an activating amount of hydrogen and the dimerization is a dehydrodimerization or cross-dimerization of a saturated hydrocarbon bearing a functional group which inactivates the saturated hydrocarbon molecule to excited mercury atom mediated photosensitized dimerization or a cross dimerization thereof with an alkane.
In a group IIb photosensitized vapor phase dimerization of an organic compound in which a gaseous mixture of a Group IIB metal and the organic compound is irradiated in a reaction zone with a photosensitizing amount of radiant energy, the improvement wherein a continuous stream of the gaseous mixture is passed as a vapor phase in a single pass through the reaction zone at a temperature at which the thus-produced dimer condenses immediately upon the formation thereof and remains condensed while exposed to the radiant energy and both the condensate and a residual vapor phase are concurrently removed from the reaction zone, thereby minimizing secondary reactions between the dimer and itself, the starting organic compound or any by-products of the dimerization reaction.
Dependencies are inferred from the claim text.