摘要:
A composition is presented for a catalyst useful in the selective hydrogenation of unconjugated diolefinic hydrocarbons to monoolefinic hydrocarbons. The catalyst comprises nickel and sulfur deposited on the surface of an alumina support. The preferred catalyst does not contain halogens, noble metals, alkaline earth metals, or alkali metals and is characterized by having only a very low percentage of the total pore volume being provided by pores having an average pore diameter less than 150 angstroms. The great majority of the pore volume is present in the form of macropores having diameters of 500 to 1500 angstroms.
摘要:
Flexible foam resistant to both photochemical and oxidative degradation result from the use of bis(N-alkylaminocyclohexyl)methanes as curing agents for polyisocyanates or polyisocyanate prepolymers. The chain extenders may be used alone or in combination with other polyamines and with polyols. Where the polyisocyanate or polyisocyanate prepolymer is also aliphatic there is outstanding resistance to yellowing.
摘要:
Rigid urea-modified polyisocyanurate foams with improved dimensional stability and flame retardancy have densities of 1-12 p.c.f., a limiting oxygen index greater than 22 and dimensional changes at 100% R.H. and 70.degree. C. of less than 2% in any linear dimension and a method of making same. The method comprises reacting an organic polyisocyanate, a blowing agent and an N,N'-dialkyl aromatic diamine in the presence of a trimerization catalyst and, if water is used as the blowing agent, a blowing catalyst, wherein the N,N'-dialkyl aromatic diamine and an amine produced by water, if used, constitute the sole sources of active hydrogen.
摘要:
Improved processes for preparation of the (S)-oxetines in high enantiomeric purity centers on resolution using simulated moving bed chromatography of a racemic precursor early in the oxetine synthesis. Resolution is effected with high enantiomeric purity, and subsequent reactions of the desired enantiomer performed with high optical specificity to maintain enantiomeric purity. The undesired enantiomer may be racemized and recycled to the resolution phase to avoid loss.
摘要:
Bis(N-alkylaminocyclohexyl)methanes are excellent chain extenders in the formation of polyurethane and polyurea polymers, both elastomers and coatings, from both monomeric polyisocyanates and isocyanate-terminated prepolymers. Our chain extenders may be used alone or in combination with other polyamines and with polyols. A broad spectrum of polymeric material can be formed with a range of diverse properties.
摘要:
A process is presented which is useful for the selective hydrogenation of polyunsaturated organic compounds. The resultant product of such a reaction produces the monoolefinic equivalents of the hydrogenated polyunsaturated organic compounds. The catalyst used in this selective hydrogenation process comprises nickel and sulfur deposited on the surface of an alumina support. The preferred catalyst does not contain halogens, noble metals, alkaline earth metals, or alkali metals and is characterized by having only a very low percentage of the total pore volume being provided by pores having an average pore diameter less than 150 angstroms. The great majority of the pore volume is present in the form of macropores having diameters of 500 to 1500 angstroms.
摘要:
Improved processes for preparation of high enantiomeric purity compounds center on resolution using simulated moving bed chromatography of a racemic precursor early in the synthesis. Resolution is effected with high enantiomeric purity, and subsequent reactions of the desired enantiomer performed with high optical specificity to maintain enantiomeric purity. The undesired enantiomer is racemized and recycled to the resolution phase to avoid loss.
摘要:
Improved processes for preparation of the (S)-oxetines in high enantiomeric purity centers on resolution using simulated moving bed chromatography of a racemic precursor early in the oxetine synthesis. Resolution is effected with high enantiomeric purity, and subsequent reactions of the desired enantiomer performed with high optical specificity to maintain enantiomeric purity. The undesired enantiomer may be racemized and recycled to the resolution phase to avoid undesired losses.
摘要:
Rigid urea-modified polyisocyanurate foams with improved dimensional stability and flame retardancy have densities of 0.5-20 p.c.f., a limiting oxygen index greater than 22 and dimensional changes at 100% R.H. and 70.degree. C. of less than 2% in any linear dimension and a method of making same. The method comprises reacting an organic polyisocyanate, a blowing agent and an N,N'-dialkyl aromatic diamine in the presence of a trimerization catalyst and, if water is used as the blowing agent, a blowing catalyst, wherein the N,N'-dialkyl aromatic diamine and an amine produced by water, if used, constitute the sole sources of active hydrogen.
摘要:
Improved processes for preparation of sertraline or sertraline analogs in high enantiomeric purity centers on resolution using simulated moving bed chromatography of isomeric racemic sertraline or sertraline analogs. Resolution is effected with high enantiomeric purity, and the undesired enantiomer may be racemized and recycled to the resolution phase to avoid loss.