Method for production of sulfhydryl compounds
AssigneeHooker Chemicals & Plastics Corporation
InventorsBobby F. Dannels, Emil J. Geering
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Abstract
An improved process is disclosed for production of sulfhydryl-terminated compounds by reaction of an allene and hydrogen sulfide initiated with ultraviolet light of wavelength above about 2600 Angstroms to obtain a colorless product of improved purity. The invention also includes the polymerization of an unsaturated hydrocarbon with the sulfhydryl-terminated product to prepare a sulfhydryl-terminated polythioether. These compounds are useful as chemical intermediates and precursors of elastomeric sealants, such as architectural sealants.
Claims13
In a process for the formation of a sulfhydryl-terminated polythioether which comprises the steps of
- 1. Condensing an allene compound and hydrogen sulfide in liquid phase to produce a sulfhydryl-terminated hydrocarbon,
- 2. Recovering the sulfhydryl-terminated hydrocarbon,
- 3. Condensing the recovered sulfhydryl-terminated hydrocarbon with an unsaturated hydrocarbon having at least one acetylenic bond or at least two ethylenic bonds to obtain the sulfhydryl-terminated polythioether,
- the improvement which comprises carrying out the step 1 reaction at a reaction temperature of about -100.degree. to about 95.degree. Centigrade, a reaction pressure of about 0 to about 3000 p.s.i.g. and a molar ratio of hydrogen sulfide to the allene compound of about 1:1 to about 20:1 in the presence of ultraviolet light of wavelength substantially above about 2600 Angstroms to obtain a sulfhydryl-terminated polythioether substantially devoid of color.
The process of 8 wherein the vitreous filter is Corex 9700.
In a process for the formation of a sulfhydryl-terminated polythioether which comprises the steps of
- 1. Condensing an allene compound and hydrogen sulfide in liquid phase to produce a sulfhydryl-terminated hydrocarbon,
- 2. Recovering the sulfhydryl-terminated hydrocarbon,
- 3. Condensing the recovered sulfhydryl-terminated hydrocarbon with a hydrocarbon having at least one acetylenic bond or at least two ethylenic bonds to obtain the sulfhydryl-terminated polythioether,
- the improvement which comprises carrying out steps 1 and 3 in the presence of ultraviolet light of wavelength substantially above about 2600 Angstroms with the step 1 reaction temperature being about -100.degree. to about 95.degree. Centigrade, the step 1 reaction pressure being about 0 to about 3000 p.s.i.g., the molar ratio of hydrogen sulfide to the allene compound in step 1 being about 1:1 to about 20:1, the step 3 reaction temperature being about -100.degree. to about 175.degree. Centigrade, the step 3 reaction pressure being about 1 to about 10 atmospheres and the molar ratio of the unsaturated hydrocarbon reactant to the sulfhydryl-terminated hydrocarbon reactant in step 3 being about 0.7:1 to about 0.999:1, whereby the reactions of steps 1 and 3 are effectively initiated and the purity of the sulfhydryl-terminated polythioether is enhanced.
In the process for the formation of a sulfhydryl-terminated polythioether which comprises polymerizing an unsaturated hydrocarbon having at least one acetylenic bond or at least two ethylenic bonds with a dithiol selected from the group consisting of 1,2 and 1,3-propanedithiol and substituted derivatives thereof which are prepared by the reaction of an allene and hydrogen sulfide, the improvement which comprises carrying out the reaction in the presence of ultraviolet light of wavelength substantially above about 2600 Angstroms at a reaction temperature of about -100.degree. to about 175.degree. Centigrade and a reaction pressure of about 1 to about 10 atmospheres and at a molar ratio of the unsaturated hydrocarbon reactant to the dithiol of about 0.7:1 to about 0.999:1 whereby the reaction is effectively initiated and the purity of the sulfhydryl-terminated polythioether is enhanced.
Dependencies are inferred from the claim text.