The present invention relates to a method for preparing an iodine-doped TiO.sub.2 nano-catalyst and use of the catalyst in heterogeneously catalyzing configuration transformation of trans-carotenoids. The iodine-doped TiO.sub.2 nano-catalyst is prepared by a sol-gel process using a titanate ester as a precursor and an iodine-containing compound as a dopant in the presence of a diluent, inhibitor and complexing agent. The catalyst exhibits high activity for isomerization of the trans-carotenoids into their cis-isomers within a short catalytic time. The catalyst can be easily prepared and is highly efficient, economical, recyclable and environmentally friendly.

The present invention relates to a method for preparing an iodine-doped TiO.sub.2 nano-catalyst and use of the catalyst in heterogeneously catalyzing configuration transformation of trans-carotenoids. The iodine-doped TiO.sub.2 nano-catalyst is prepared by a sol-gel process using a titanate ester as a precursor and an iodine-containing compound as a dopant in the presence of a diluent, inhibitor and complexing agent. The catalyst exhibits high activity for isomerization of the trans-carotenoids into their cis-isomers within a short catalytic time. The catalyst can be easily prepared and is highly efficient, economical, recyclable and environmentally friendly.

In one aspect, the invention provides a method for synthesizing a fatty olefin derivative. The method includes: a) contacting an olefin according to Formula I

##STR00001##

with a metathesis reaction partner according to Formula IIb

##STR00002##

in the presence of a metathesis catalyst under conditions sufficient to form a metathesis product according to Formula IIIb:

##STR00003##

and b) converting the metathesis product to the fatty olefin derivative. Each R.sup.1 is independently selected from H, C.sub.1-18 alkyl, and C.sub.2-18 alkenyl; R.sup.2b is C.sub.1-8 alkyl; subscript y is an integer ranging from 0 to 17; and subscript z is an integer ranging from 0 to 17. In certain embodiments, the metathesis catalyst is a tungsten catalyst or a molybdenum catalyst. In various embodiments, the fatty olefin derivative is a pheromone. Pheromone compositions and methods of using them are also described.

In one aspect, the invention provides a method for synthesizing a fatty olefin derivative. The method includes: a) contacting an olefin according to Formula I

##STR00001##

with a metathesis reaction partner according to Formula IIb

##STR00002##

in the presence of a metathesis catalyst under conditions sufficient to form a metathesis product according to Formula IIIb:

##STR00003##

and b) converting the metathesis product to the fatty olefin derivative. Each R.sup.1 is independently selected from H, C.sub.1-18 alkyl, and C.sub.2-18 alkenyl; R.sup.2b is C.sub.1-8 alkyl; subscript y is an integer ranging from 0 to 17; and subscript z is an integer ranging from 0 to 17. In certain embodiments, the metathesis catalyst is a tungsten catalyst or a molybdenum catalyst. In various embodiments, the fatty olefin derivative is a pheromone. Pheromone compositions and methods of using them are also described.

Methods and compositions for stabilization and subsequent hydrogenation of a microbial-derived immiscible olefin are described. The methods comprise providing a feed stream to the inlet of a reactor, wherein the feed stream comprises a microbial-derived immiscible olefin composition stabilized with a phenolic antioxidant which is a phenol derivative containing an unfused phenyl ring with one or more hydroxyl substituents. The methods further comprise contacting the feed stream with hydrogen in the presence of a hydrogenation catalyst at a temperature of about 20 C. or greater, and generating a product stream comprising a hydrogenated immiscible olefin composition. The microbial-derived immiscible olefin composition stabilized with the phenolic antioxidant remains stable over time, and its hydrogenation reaction time and process are improved.

Methods and compositions for stabilization and subsequent hydrogenation of a microbial-derived immiscible olefin are described. The methods comprise providing a feed stream to the inlet of a reactor, wherein the feed stream comprises a microbial-derived immiscible olefin composition stabilized with a phenolic antioxidant which is a phenol derivative containing an unfused phenyl ring with one or more hydroxyl substituents. The methods further comprise contacting the feed stream with hydrogen in the presence of a hydrogenation catalyst at a temperature of about 20 C. or greater, and generating a product stream comprising a hydrogenated immiscible olefin composition. The microbial-derived immiscible olefin composition stabilized with the phenolic antioxidant remains stable over time, and its hydrogenation reaction time and process are improved.

Methods and compositions for stabilization and subsequent hydrogenation of a microbial-derived immiscible olefin are described. The methods comprise providing a feed stream to the inlet of a reactor, wherein the feed stream comprises a microbial-derived immiscible olefin composition stabilized with a phenolic antioxidant which is a phenol derivative containing an unfused phenyl ring with one or more hydroxyl substituents. The methods further comprise contacting the feed stream with hydrogen in the presence of a hydrogenation catalyst at a temperature of about 20 C. or greater, and generating a product stream comprising a hydrogenated immiscible olefin composition. The microbial-derived immiscible olefin composition stabilized with the phenolic antioxidant remains stable over time, and its hydrogenation reaction time and process are improved.

An improved method for preparing squalene from a squalene-containing composition, said method comprising the steps of (a) a purification distillation carried out at a temperature T.sub.1 (b) a denaturing distillation carried out at a temperature T.sub.2; wherein steps (a) and (b) may be performed in either order; T.sub.1 and T.sub.2 are sufficient to cause squalene to boil; T.sub.2>T.sub.1; and T.sub.2>200 C.

An improved method for preparing squalene from a squalene-containing composition, said method comprising the steps of (a) a purification distillation carried out at a temperature T.sub.1 (b) a denaturing distillation carried out at a temperature T.sub.2; wherein steps (a) and (b) may be performed in either order; T.sub.1 and T.sub.2 are sufficient to cause squalene to boil; T.sub.2>T.sub.1; and T.sub.2>200 C.

An improved method for preparing squalene from a squalene-containing composition, said method comprising the steps of (a) a purification distillation carried out at a temperature T.sub.1 (b) a denaturing distillation carried out at a temperature T.sub.2; wherein steps (a) and (b) may be performed in either order; T.sub.1 and T.sub.2 are sufficient to cause squalene to boil; T.sub.2>T.sub.1; and T.sub.2>200 C.