A dissymmetric RN,N-dialkylamides of formula (I) in which: R.sup.1 represents a linear C.sub.1 to C.sub.4 alkyl, R.sup.2 represents a linear C.sub.1 to C.sub.10 alkyl, and R.sup.3 represents a linear or branched C.sub.6 to C.sub.15 alkyl, where R.sup.3 is different from a n-octyl, n-decyl, n-dodecyl, 2-ethylhexyl and 2-ethyloctyl group when R.sup.1 represents a n-butyl group and R.sup.2 represents an ethyl group. A method for synthesising the N,N-dialkylamides, and uses of same for extracting uranium and/or plutonium from an aqueous acid solution or for fully or partially separating the uranium from the plutonium contained in an aqueous acid solution and a solution resulting from the dissolution of spent nuclear fuel in nitric acid. A method for treating an aqueous solution resulting from the dissolution of spent nuclear fuel in nitric acid, which allows the uranium and the plutonium contained in the solution to be extracted, separated and decontaminated in a single cycle.

A dissymmetric RN,N-dialkylamides of formula (I) in which: R.sup.1 represents a linear C.sub.1 to C.sub.4 alkyl, R.sup.2 represents a linear C.sub.1 to C.sub.10 alkyl, and R.sup.3 represents a linear or branched C.sub.6 to C.sub.15 alkyl, where R.sup.3 is different from a n-octyl, n-decyl, n-dodecyl, 2-ethylhexyl and 2-ethyloctyl group when R.sup.1 represents a n-butyl group and R.sup.2 represents an ethyl group. A method for synthesising the N,N-dialkylamides, and uses of same for extracting uranium and/or plutonium from an aqueous acid solution or for fully or partially separating the uranium from the plutonium contained in an aqueous acid solution and a solution resulting from the dissolution of spent nuclear fuel in nitric acid. A method for treating an aqueous solution resulting from the dissolution of spent nuclear fuel in nitric acid, which allows the uranium and the plutonium contained in the solution to be extracted, separated and decontaminated in a single cycle.

A method for desalinating a salt-containing polymer (SP) comprising a polyaryl ether having a softening temperature T.sub.S and a salt (S), comprising the steps of a) providing the salt-containing polymer (SP) at a first temperature T.sub.1 above the softening temperature T.sub.S of the polyaryl ether, b) contacting the salt-containing polymer (SP) provided in step a) with an extractant (E) to obtain a desalinated polymer (DP) comprising the polyaryl ether, and a salt-containing extractant (SE) comprising the extractant (E) and the salt (S).

[Problem] To provide a novel means capable of generating highly stereoselective and/or highly efficient amidation reactions in a variety of substrates having a carboxyl group and an amino group, and capable of producing amide compounds.

[Solution] A reaction agent for amide reactions between carboxyl groups and amino groups and including a silane compound indicated by general formula (A) and/or general formula (B).

##STR00001##

(In general formulas (A) and (B), each substituent represents the definition described in the Claims.)

[Problem] To provide a novel means capable of generating highly stereoselective and/or highly efficient amidation reactions in a variety of substrates having a carboxyl group and an amino group, and capable of producing amide compounds.

[Solution] A reaction agent for amide reactions between carboxyl groups and amino groups and including a silane compound indicated by general formula (A) and/or general formula (B).

##STR00001##

(In general formulas (A) and (B), each substituent represents the definition described in the Claims.)

A method for producing N-vinylacetamide includes a feeding step of feeding a raw material containing N-(1-methoxyethyl)acetamide (MEA) to an evaporator, an evaporation step of evaporating, by the evaporator, the raw material, to form a vaporized raw material, a superheating step of feeding the vaporized raw material to a superheater, and superheating the vaporized raw material such that a superheating temperature of the vaporized raw material is equal to or more than a temperature higher by 5° C. than a boiling point of the N-(1-methoxyethyl)acetamide (MEA) under an inner pressure of the superheater and equal to or less than 200° C., and a thermal decomposition step of feeding the superheated vaporized raw material to a thermal decomposition reactor, to thermally decompose the superheated vaporized raw material, and a content of the N-(1-methoxyethyl)acetamide in the raw material is from 80 to 100 mass %.

A method for producing N-vinylacetamide includes a feeding step of feeding a raw material containing N-(1-methoxyethyl)acetamide (MEA) to an evaporator, an evaporation step of evaporating, by the evaporator, the raw material, to form a vaporized raw material, a superheating step of feeding the vaporized raw material to a superheater, and superheating the vaporized raw material such that a superheating temperature of the vaporized raw material is equal to or more than a temperature higher by 5° C. than a boiling point of the N-(1-methoxyethyl)acetamide (MEA) under an inner pressure of the superheater and equal to or less than 200° C., and a thermal decomposition step of feeding the superheated vaporized raw material to a thermal decomposition reactor, to thermally decompose the superheated vaporized raw material, and a content of the N-(1-methoxyethyl)acetamide in the raw material is from 80 to 100 mass %.

Polyethylene glycol derivatives of the following formula I and uses thereof are disclosed. A method for manufacturing the polyethylene glycol derivatives is also disclosed.

##STR00001##

Polyethylene glycol derivatives of the following formula I and uses thereof are disclosed. A method for manufacturing the polyethylene glycol derivatives is also disclosed.

##STR00001##

The present invention provides a process for preparing 2-methyl-N-(2′-methylbutyl)butanamide of the following formula (1):the process comprising: subjecting an α-arylethyl-2-methylbutylamine compound of the following general formula (2): wherein Ar represents a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, to N-2-methylbutyrylation to form an N-α-arylethyl-2-methyl-N-(2′-methylbutyl)butanamide compound of the following general formula (3): wherein Ar is as defined above, and removing the α-arylethyl group of the resulting compound (3) to form 2-methyl-N-(2′-methylbutyl)butanamide (1).

##STR00001##