The Dow Chemical Company

Edwin J Strojny

Hans R Friedli

Milton S Wing

Richard R Klimpel

Robert D Hansen

Ralph D Priester, Jr

Debra H Stutts

Polyurethanes are produced from compositions comprising at least one relatively high equivalent weight component and at least one chain extender selected from the group consisting of heterocyclic diamines, diaromatic disulfides, alkyl ethers of halogen-substituted aromatic diamines, polysubstituted alkyl diamines and alkyl acid esters of halogen-substituted diamino phenols of designated structures. Polyurethanes having high thermal stability, high tear strength and high modulus are produced.

Chain extenders for polyurethanes

This invention relates to a froth flotation process for selectively recovering metal-containing sulfide or sulfidized metal-containing oxide minerals from ores using a froth flotation process. The collector employed in the process is an organic monosulfide of the formula:

Novel collectors for the selective froth flotation of mineral sulfides

This invention relates to a froth flotation process for selectively recovering nonferrous metal-containing sulfide minerals or sulfidized metal-containing oxide minerals from ores using froth flotation. The collector employed in the process is an epithio compound of the formula: ##STR1## wherein m=1, 2 or 3; each R is independently hydrogen, a hydrocarbyl group or substituted hydrocarbyl group; each R.sup.1 is independently hydrogen, a hydrocarbyl group or substituted hydrocarbyl group, provided one R or R.sup.1 is not hydrogen; and each R.sup.2 is independently hydrogen, hydrocarbyl, hydrocarbyloxy or hydrocarbyl thioether.

An improved vapor phase process for producing aldehydes from corresponding carboxylic acids and esters of said carboxylic acids by contacting the acid or ester at temperatures from about 300.degree. C. to about 500.degree. C. with hydrogen, in the presence of a catalyst selected from certain metal oxides.

Method of preparing aldehydes

A catalyst for, and method of, producing a reaction product predominantly of maleic anhydride, that is a product of reaction containing a ratio of maleic to citraconic anhydrides of at least 25 to 1, respectively, and preferably greater than about 100 to 1, respectively, by reacting a feed stream consisting of oxygen or an oxygen-containing gas and an organic C.sub.5 feed predominantly of piperylene and dicyclopentadiene, and preferably predominantly dicyclopentadiene, at bath temperatures of from about 360.degree. to about 450.degree. C. over a catalyst comprising a mixture of 25 to 60 weight percent titanium oxide (TiO.sub.2), 5 to 40 weight percent molybdenum oxide (MoO.sub.3) and 30 to 60 weight percent vanadium oxide (V.sub.2 O.sub.5) on an alpha alumina or alumina-silica carrier having less than about one square meter per gram (&lt;1 m.sup.2 /g) surface area. The feed rate of the reactants is preferably between about 1,500 and about 15,000 gas hourly space velocity; the C.sub.5 hydrocarbon content of the feed gases being between about 0.5 and 1.8 volume percent.

Method of producing maleic anhydride

A catalyst for, and method of, producing a reaction product predominantly of maleic anhydride, that is a product of reaction containing a ratio of maleic to citraconic anhydrides of at least 25 to 1, respectively, and preferably greater than about 100 to 1, respectively, by reacting a feed stream consisting of oxygen or an oxygen-containing gas and an organic C.sub.5 feed predominantly of piperylene and dicyclopentadiene, and preferably predominantly dicyclopentadiene, at bath temperatures of from about 360.degree. to about 450.degree. C. over a catalyst comprising a mixture of 25 to 60 weight percent titanium oxide (TiO.sub.2), 5 to 40 weight percent molybdenum oxide (MoO.sub.3) and 30 to 60 weight percent vanadium oxide (V.sub.2 O.sub.5) on an alpha alumina or alumina-silica carrier having less than about one square meter per gram (&lt;1 m.sup.2 /g) surface area.

Catalyst for producing maleic anhydride

A catalyst for, and method of, producing a reaction product predominantly of maleic anhydride, that is a product of reaction containing a ratio of maleic to citraconic anhydrides of at least 25 to 1, respectively, and preferably greater than about 100 to 1, respectively, by reacting a feed stream consisting of oxygen or an oxygen-containing gas and an organic C.sub.5 feed predominantly of piperylene and dicyclopentadiene, and preferably predominantly dicyclopentadiene, at bath temperatures of from about 360.degree. to about 450.degree. C over a catalyst comprising a mixture of 25 to 60 weight percent titanium oxide (TiO.sub.2), 5 to 40 weight percent molybdenum oxide (MoO.sub.3) and 30 to 60 weight percent vanadium oxide (V.sub.2 O.sub.5) on an alpha alumina or alumina-silica carrier having less than about one square meter per gram (&lt;1 m.sup.2 /g) surface area. The feed rate of the reactants is preferably between about 1,500 and about 15,000 gas hourly space velocity; the C.sub.5 hydrocarbon content of the feed gases being between about 0.5 and 1.8 volume percent.

Catalyst for and method of producing maleic anhydride

Citraconic anhydride is made by the vanadium-catalyzed gas-phase air oxidation of mesityl oxide at about 200-500.degree.C. and atmospheric pressure with a contact time of less than 1 second. Preferred catalysts are vanadium oxide and vanadate salts. Preferred O.sub.2 /mesityl oxide molar ratios are about 10:1 to 100:1.

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Midland, MI, United States of America

Edwin J Strojny