The disclosure provides recording materials including aromatic substituted ethane-core derivatized monomers and polymers for use in volume Bragg gratings, including, but not limited to, volume Bragg gratings for holography applications. Several structures are disclosed for monomers and polymers for use in Bragg gratings applications, leading to materials with higher refractive index, low birefringence, and high transparency. The disclosed derivatized monomers and polymers thereof can be used in any volume Bragg gratings materials, including two-stage polymer materials where a matrix is cured in a first step, and then the volume Bragg grating is written by way of a second curing step of a monomer.

The present invention discloses processes for producing methyl ethyl sulfide by contacting dimethyl sulfide and diethyl sulfide in the presence of a suitable catalyst. Methyl ethyl sulfide can be used as an odorant in natural gas. Integrated mercaptan and sulfide manufacturing systems and integrated methods for making mercaptans and sulfides also are disclosed.

The present invention discloses processes for producing methyl ethyl sulfide by contacting dimethyl sulfide and diethyl sulfide in the presence of a suitable catalyst. Methyl ethyl sulfide can be used as an odorant in natural gas. Integrated mercaptan and sulfide manufacturing systems and integrated methods for making mercaptans and sulfides also are disclosed.

The present invention discloses processes for producing methyl ethyl sulfide by contacting dimethyl sulfide and diethyl sulfide in the presence of a suitable catalyst. Methyl ethyl sulfide can be used as an odorant in natural gas. Integrated mercaptan and sulfide manufacturing systems and integrated methods for making mercaptans and sulfides also are disclosed.

The present invention discloses processes for producing methyl ethyl sulfide by contacting dimethyl sulfide and diethyl sulfide in the presence of a suitable catalyst. Methyl ethyl sulfide can be used as an odorant in natural gas. Integrated mercaptan and sulfide manufacturing systems and integrated methods for making mercaptans and sulfides also are disclosed.

Polythioether polymers, sealants containing polythioether polymers, and compounds useful as stabilizing monomers in the manufacture of polythioether polymers are provided. In many embodiments the polymers and sealants demonstrate reduced risk of spoilage that may be caused by low temperature storage of the polymer or uncured sealant. Compounds useful as stabilizing monomers include compounds according to formula I:
CH.sub.2CR.sup.1CHR.sup.2SR.sup.3SCHR.sup.4CR.sup.5CH.sub.2[I]
wherein R.sup.1, R.sup.2, R.sup.4 and R.sup.5 are independently selected from H, CH.sub.3 or C.sub.2H.sub.5, and
wherein R.sup.3 is selected from divalent groups comprising 2-12 carbon atoms, 0-5 ether oxygen atoms and 0-5 thioether sulfur atoms, which may be straight, branched or cyclic.

Polythioether polymers, sealants containing polythioether polymers, and compounds useful as stabilizing monomers in the manufacture of polythioether polymers are provided. In many embodiments the polymers and sealants demonstrate reduced risk of spoilage that may be caused by low temperature storage of the polymer or uncured sealant. Compounds useful as stabilizing monomers include compounds according to formula I:
CH.sub.2CR.sup.1CHR.sup.2SR.sup.3SCHR.sup.4CR.sup.5CH.sub.2[I]
wherein R.sup.1, R.sup.2, R.sup.4 and R.sup.5 are independently selected from H, CH.sub.3 or C.sub.2H.sub.5, and
wherein R.sup.3 is selected from divalent groups comprising 2-12 carbon atoms, 0-5 ether oxygen atoms and 0-5 thioether sulfur atoms, which may be straight, branched or cyclic.

The present invention discloses processes for producing methyl ethyl sulfide by contacting dimethyl sulfide and diethyl sulfide in the presence of a suitable catalyst. Methyl ethyl sulfide can be used as an odorant in natural gas. Integrated mercaptan and sulfide manufacturing systems and integrated methods for making mercaptans and sulfides also are disclosed.

The present invention discloses processes for producing methyl ethyl sulfide by contacting dimethyl sulfide and diethyl sulfide in the presence of a suitable catalyst. Methyl ethyl sulfide can be used as an odorant in natural gas. Integrated mercaptan and sulfide manufacturing systems and integrated methods for making mercaptans and sulfides also are disclosed.

A process for the preparation of a polyunsaturated thiol comprising: (1) reacting a polyunsaturated alcohol in the presence of a compound of formula R.sub.2SO.sub.2Hal wherein R.sub.2 is a C.sub.1-20 hydrocarbyl group, such an C.sub.1-10 alkyl group, to form a polyunsaturated sulphonyl ester; (2) converting the polyunsaturated sulphonyl ester to a polyunsaturated thioester by reacting with an anion of formula .sup.SC(O)R.sub.4 wherein R.sub.4 is a C.sub.1-20 hydrocarbyl group; (3) converting the polyunsaturated thioester to form a polyunsaturated thiol optionally in the presence of an antioxidant, e.g. using a metal carbonate. (4) reacting said polyunsaturated thiol with a compound (LG)R.sup.3COX wherein X is an electron withdrawing A group and R.sup.3 is an alkylene group carrying a leaving group (LG), such as LG-CH.sub.2 forming (I) where X is an electron withdrawing group and LG is a leaving group; optionally in the presence of an antioxidant, so as to form a polyunsaturated ketone compound.

##STR00001##