A process for continuous production of C.sub.2-C.sub.4-monoalkanolamines by reaction of a corresponding C.sub.2-C.sub.4-alkylene oxide with a molar excess of ammonia (NH.sub.3), wherein aqueous ammonia is employed, in the liquid phase and in the presence of an acidic cation exchanger as catalyst which contains a crosslinked copolymer comprising acidic functional groups as the carrier matrix, wherein the cation exchanger has a total exchange capacity of not less than 1.8 eq/L.

An object of the invention is to provide an .sup.11C-labeled catechol derivative having sufficient radioactivity to obtain an imaging image by a PET apparatus, a PET probe of a phosphorylated tau aggregation inhibitor using the same, and a method for producing them. The .sup.11C-labeled catechol derivative of the present invention is represented by the following general formula (a) (wherein R is a substituent having an isopropylamino group, and the carbon at the 2-position of the isopropylamino group is labeled with .sup.11C). ##STR00001##

A gasoline fuel composition comprising as an additive an ester compound which is the reaction product of an optionally substituted polycarboxylic acid or an anhydride thereof and an alcohol or formula H—(OR).sub.n—OR.sup.1, wherein R is an optionally substituted alkylene group; R.sup.1 is hydrogen or an optionally substituted hydrocarbyl group, and n is 0 or a positive integer; wherein n is not O when R.sup.1 is hydrogen.

A process for continuous production of C.sub.2-C.sub.4-monoalkanolamines by reaction of a corresponding C.sub.2-C.sub.4-alkylene oxide with a molar excess of ammonia (NH.sub.3), wherein aqueous ammonia is employed, in the liquid phase and in the presence of an acidic cation exchanger as catalyst which contains a crosslinked copolymer comprising acidic functional groups as the carrier matrix, wherein the cation exchanger has a total exchange capacity of not less than 1.8 eq/L.

A process for continuous production of C.sub.2-C.sub.4-monoalkanolamines by reaction of a corresponding C.sub.2-C.sub.4-alkylene oxide with a molar excess of ammonia (NH.sub.3), wherein aqueous ammonia is employed, in the liquid phase and in the presence of an acidic cation exchanger as catalyst which contains a crosslinked copolymer comprising acidic functional groups as the carrier matrix, wherein the cation exchanger has a total exchange capacity of not less than 1.8 eq/L.

A process for continuous production of C.sub.2-C.sub.4-monoalkanolamines by reaction of a corresponding C.sub.2-C.sub.4-alkylene oxide with a molar excess of ammonia (NH.sub.3), wherein aqueous ammonia is employed, in the liquid phase and in the presence of an acidic cation exchanger as catalyst which contains a crosslinked copolymer comprising acidic functional groups as the carrier matrix, wherein the cation exchanger has a total exchange capacity of not less than 1.8 eq/L.

There is herein provided a compound of formula (I) or a pharmaceutically acceptable salt thereof, wherein X, R.sup.1, R.sup.2, R.sup.3, R.sup.4 and n have meanings as provided in the description. ##STR00001##

There is herein provided a compound of formula (I) or a pharmaceutically acceptable salt thereof, wherein X, R.sup.1, R.sup.2, R.sup.3, R.sup.4 and n have meanings as provided in the description. ##STR00001##

A process for the conversion of glycolaldehyde with an aminating agent in the presence of hydrogen and of a catalyst in a glycolaldehyde conversion reactor, wherein one or more organic carboxylic acids are fed into the glycolaldehyde conversion reactor.

A process for the conversion of glycolaldehyde with an aminating agent in the presence of hydrogen and of a catalyst in a glycolaldehyde conversion reactor, wherein one or more organic carboxylic acids are fed into the glycolaldehyde conversion reactor.