A quaternary ammonium salt of formula wherein each of R.sup.1, R.sup.2, R.sup.3 and R.sup.4 is independently selected from an optionally substituted alkyl, alkenyl or aryl group having less than 8 carbon atoms and R.sup.5 is hydrogen or an optionally substituted hydrocarbyl group.

##STR00001##

Amines and amine derivatives that improve the buffering range, and/or reduce the chelation and other negative interactions of the buffer and the system to be buffered. The reaction of amines or polyamines with various molecules to form polyamines with differing pKa's will extend the buffering range, derivatives that result in polyamines that have the same pKa yields a greater buffering capacity. Derivatives that result in zwitterionic buffers improve yield by allowing a greater range of stability.

Amines and amine derivatives that improve the buffering range, and/or reduce the chelation and other negative interactions of the buffer and the system to be buffered. The reaction of amines or polyamines with various molecules to form polyamines with differing pKa's will extend the buffering range, derivatives that result in polyamines that have the same pKa yields a greater buffering capacity. Derivatives that result in zwitterionic buffers improve yield by allowing a greater range of stability.

An absorbent for selective removal of hydrogen sulfide over carbon dioxide from a fluid stream comprises an aqueous solution of a) a tertiary amine, b) a sterically hindered secondary amine of the general formula (I) ##STR00001##
in which R.sub.1 and R.sub.2 are each independently selected from C.sub.1-4-alkyl and C.sub.1-4-hydroxyalkyl; R.sub.3, R.sub.4, R.sub.5 and R.sub.6 are each independently selected from hydrogen, C.sub.1-4-alkyl and C.sub.1-4-hydroxyalkyl, with the proviso that at least one R.sub.4 and/or R.sub.5 radical on the carbon atom bonded directly to the nitrogen atom is C.sub.1-4-alkyl or C.sub.1-4-hydroxyalkyl when R.sub.3 is hydrogen; x and y are integers from 2 to 4 and z is an integer from 1 to 4; where the molar ratio of b) to a) is in the range from 0.05 to 1.0, and c) an acid in an amount, calculated as neutralization equivalent relative to the protonatable nitrogen atoms in a) and b), of 0.05 to 15.0%. One preferred amine of the formula I is 2-(2-tert-butylaminoethoxy)ethanol. The absorbent allows a defined H.sub.2S selectivity to be set at pressures of the kind typical in natural gas processing.

Disclosed herein are polymers formed by the condensation of bis(hydroxycarbyl)-aminophenolic compounds with aldehydes. The condensation polymers include one or more repeat units having bis(hydroxycarbyl)amino functionality. The hydroxyl groups of the bis(hydroxycarbyl)amino functionalities are available for further condensation with an epoxide, such as ethylene oxide, to yield a polyalkoxylated polymer. The polymers are useful as antipolymerants, polymerization retardants, surfactants, or a combination of these in one or more industrial systems.

Polymers are formed by the condensation of bis(hydroxycarbyl)-aminophenolic compounds with aldehydes. The condensation polymers include one or more repeat units having bis(hydroxycarbyl)amino functionality. The polymers are useful as antifoulants, antipolymerants, rheology modifiers, dehazers, polymerization retardants, surfactants, or a combination of these in one or more industrial process streams.

Disclosed is a compound of formula I or a pharmaceutically acceptable hydrate, solvate, crystal, co-crystal, enantiomer, stereoisomer, polymorph or prodrug thereof, which is useful for treatment of eye disorders, skin diseases and/or complications associated therewith. Also disclosed is a pharmaceutical composition comprising as an active ingredient at least one compound of formula I and a pharmaceutically acceptable excipient. Also disclosed is a method of treating an eye disorder, skin disease and/or a complication thereof in a subject in need thereof by administering at least one compound of formula I or a pharmaceutically acceptable hydrate, solvate, crystal, co-crystal, enantiomer, stereoisomer, polymorph or prodrug thereof.

Provided is a compound which may be obtained by esterification condensation of components as described herein. The compound may be used as a collector for ore enrichment (flotation), as a corrosion inhibitor, as a viscosity enhancer, emulsifier or stabilizer that is useful for the oil and gas industry, as a clay modifier, as an adhesion promoter, as an antiagglomerant additive, as an additive in haircare products, as a fabric softener, as an antistatic agent in polymers, as a bitumen emulsion additive, as a detergency cationic agent, as a fertilizer additive, as an antiagglomerant for hydrates, as a lubrication or adhesion-promoting additive, for example.

Provided is a compound which may be obtained by esterification condensation of components as described herein. The compound may be used as a collector for ore enrichment (flotation), as a corrosion inhibitor, as a viscosity enhancer, emulsifier or stabilizer that is useful for the oil and gas industry, as a clay modifier, as an adhesion promoter, as an antiagglomerant additive, as an additive in haircare products, as a fabric softener, as an antistatic agent in polymers, as a bitumen emulsion additive, as a detergency cationic agent, as a fertilizer additive, as an antiagglomerant for hydrates, as a lubrication or adhesion-promoting additive, for example.

A method of producing a compound represented by formula (3):

##STR00001##

includes: step (1) of performing coupling of a monodispersed polyethylene glycol derivative represented by formula (4) shown below with a compound represented by formula (5) shown below using a base catalyst having a pKa in an aqueous solution of 15 to 20 to obtain a compound represented by formula (6) shown below, step (2) of deprotecting the protective group A of the compound represented by the formula (6) to obtain a compound represented by formula (7) shown below, and step (3) of subjecting the compound represented by the formula (7) to separatory purification; and step (4) of subjecting the compound represented by the formula (7) to deprotection treatment or reduction treatment to obtain the compound represented by formula (3), in an order described above, where Y.sup.2, n, A, B, and Z are as defined herein:

##STR00002##