Organic compounds -- part of the class 532-570 series – Organic compounds – Unsubstituted hydrocarbyl chain between the ring and the -c-...
Reexamination Certificate
2002-06-19
2003-09-23
Kumar, Shailendra (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Unsubstituted hydrocarbyl chain between the ring and the -c-...
C540S533000, C540S604000, C546S243000, C548S543000, C548S552000
Reexamination Certificate
active
06624303
ABSTRACT:
The present invention leads to an improved process for preparing N-alkenyl-amides by reacting the corresponding NH-amides with acetylenes in the liquid phase in the presence of basic alkali metal compounds and a cocatalyst.
N-Alkenyl-amides are used as monomers in the manufacture of plastics and paints. Polyvinylamides are used for example as laundry detergent assistants, as auxiliaries in cosmetic and medical products and also for stabilizing and clarifying beers and fruit juices. Polyvinyl-lactams, especially polyvinylpyrrolidone polymers, are widely used, for example as dispersants for pigments, as laundry detergent assistants, as auxiliaries in cosmetic and medical products and also as auxiliaries in textile processing and adhesive technology.
N-Alkenyl-lactams are produced on an industrial scale by reacting the corresponding NH-lactams with acetylenes in the presence of basic catalysts (see W. Reppe et al., Justus Liebigs Ann. Chem., 601 (1956) page 135-8 and DE-Auslegeschrift 1 163 835).
DE-Offenlegungsschrift 3 215 093 discloses a process for vinylating 2-pyrrolidone with ethyne in the presence of basic catalysts and in the additional presence of a polyoxyalkylene compound as cocatalyst. Useful polyoxyalkylene compounds are said to be crown ethers (eg 18-crown-6), polyoxyethylene, polyoxypropylene, selectively capped by alkyl or phenyl groups. Conversions up to 63% and selectivities around 90% are reported, the corresponding yield being not more 57%. The formation of polymeric residues is reduced. However, the cocatalysts mentioned are costly materials which are generally not recoverable, since they have high boiling points and therefore remain in the distillation bottoms together with the polymeric byproducts. In addition, they are not stable in the strongly basic medium of the reaction.
U.S. Pat. No. 5,665,889 describes a method for the production of N-vinyl-2-pyrrolidone from 2-pyrrolidone and ethyne in the presence of basic alkali metal compounds using cocatalysts comprising hydroxy end-capped ether oligomers, for example polytetrahydrofuran, or linear diols having at least 4 carbon atoms, for example, 1,4-butanediol. The vinylation takes place at a temperature ranging from 100 to 200° C., and at a pressure ranging from 7.5 to 30 atm (from 7.6 to 30 bar) in the course of a reaction time of several hours. The use of 1,4-butanediol produced a yield of only 77.2% even after a reaction time of 4 hours. The present inventors have determined that these cocatalysts, which have high boiling points, are generally impossible to separate from the polymeric byproducts or in the case of the use of 1,4-butanediol can be separated from the product of value only by means of inconvenient distillative or chemical methods.
It is an object of the present invention to develop a process for preparing N-alkenyl-amides that does not have the recited disadvantages, that permits yields of more than 80% and that makes the pure product obtainable in a simple manner.
We have found that this object is achieved by a process for preparing N-alkenyl-amides by reacting the corresponding NH-amides with acetylenes in the liquid phase in the presence of basic alkali metal compounds and of a cocatalyst, which comprises using as the cocatalyst compounds of the general formulae (Ia) and/or (Ib)
R
1
O—(CH
2
CH
2
CH
2
CH
2
O)
n
—H (Ia):
R
1
O—(CH
2
CH
2
CH
2
CH
2
O)
n
—R
2
, (Ib):
where n is 1, 2 or 3 and R
1
and R
2
are independently C
1
- to C
6
-alkyl or C
2
- to C
6
-alkenyl, or together a butenyl unit.
The process of the invention provides N-alkenyl-amides in high selectivity and high yield from the corresponding NH amides and acetylenes in the presence of basic alkali metal compounds and of an inexpensive cocatalyst which is simple to remove again from the reaction mixture.
An essential feature of the process according to the invention is the presence of a cocatalyst (Ia) and/or (Ib)
R
1
O—(CH
2
CH
2
CH
2
CH
2
O)
n
—H (Ia):
R
1
O—(CH
2
CH
2
CH
2
CH
2
O)
n
—R
2
, (Ib):
where n is 1, 2 or 3
and R
1
and R
2
are independently branched or unbranched C
1
- to C
6
-alkyl, for example methyl, ethyl, propyl, 1-methylethyl, butyl, 1-methylpropyl, 2-methylpropyl, 1,1-dimethylethyl, pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 2,2-dimethylpropyl, 1-ethylpropyl, hexyl, 1,1-dimethylpropyl, 1,2-dimethylpropyl, 1-methylpentyl, 2-methylpentyl, 3-methylpentyl, 4-methylpentyl, 1,1-dimethylbutyl, 1,2-dimethylbutyl, 1,3-dimethylbutyl, 2,2-dimethylbutyl, 2,3-dimethylbutyl, 3,3-dimethylbutyl, 1-ethylbutyl, 2-ethylbutyl, 1,1,2-trimethylpropyl, 1,2,2-trimethylpropyl, 1-ethyl-1-methylpropyl and 1-ethyl-2-methylpropyl,
or branched or unbranched C
2
- to C
6
-alkenyl having a double bond in any desired position, for example ethenyl (vinyl), 1-propenyl, 2-propenyl, 1-methylethenyl, 1-butenyl, 2-butenyl, 3-butenyl, 1-methyl-1-propenyl, 2-methyl-1-propenyl, 1-methyl-2-propenyl, 2-methyl-2-propenyl, 1-pentenyl, 2-pentenyl, 3-pentenyl, 4-pentenyl, 1-hexenyl, 2-hexenyl, 3-hexenyl, 4-hexenyl and 5-hexenyl,
or R
1
and R
2
are together a butenyl unit, specifically CH
2
CH
2
CH
2
CH
2
,
or mixtures thereof.
Examples of useful cocatalysts (Ia) and/or (Ib) for the process of the invention are 4-methoxy-1-butanol, 4-ethoxy-1-butanol, 4-propoxy-1-butanol, 4-butoxy-1-butanol, 1,4-dimethoxybutane, 1,4-diethoxybutane, 1,4-dipropoxybutane, 1,4-dibutoxybutane, 1-ethoxy-4-methoxybutane, 1-propoxy-4-methoxybutane, 1-butoxy-4-methoxybutane, 1-propoxy-4-ethoxybutane, 1-butoxy-4-ethoxybutane, 1-butoxy-4-propoxybutane, 4-vinyloxy-1-butanol, 4-(isopropenyloxy)-1-butanol, 4-propenyloxy-1-butanol, 1,4-divinyloxybutane, 1,4-bis(isopropenyloxy)butane, 1,4-bis(propenyloxy)butane, 1-vinyloxy-4-methoxybutane, 1-vinyloxy-4-ethoxybutane, 1-vinyloxy-4-propoxybutane, 1-(isopropenyloxy)-4-propoxybutane, 1-(propenyloxy)-4-propoxybutane, 4-(4′-methoxy-1′-butoxy)-1-butanol, 4-(4′-ethoxy-1′-butoxy)-1-butanol, 4-(4′-vinyloxy-1′-butoxy)-1-butanol, bis(4-methoxy-1-butyl) ether, bis(4-ethoxy-1-butyl) ether, bis(4-vinyloxy-1-butyl) ether, 10-crown-2, 15-crown-3 and 20-crown-4.
Preference is given to using cocatalysts of the formulae (Ia) and/or (Ib) where R
1
and R
2
are independently ethyl or vinyl, for example 4-ethoxy-1-butanol, 1,4-diethoxybutane, 4-vinyloxy-1-butanol, 1,4-divinyloxybutane, 1-vinyloxy-4-ethoxybutane, 4-(4′-ethoxy-1′-butoxy)-1-butanol, 4-(4′-vinyloxy-1′-butoxy)-1-butanol, bis(4-ethoxy-1-butyl) ether and bis(4-vinyloxy-1-butyl) ether or mixtures thereof.
Particular preference is given to using 4-ethoxy-1-butanol, 1,4-diethoxybutane, 4-vinyloxy-1-butanol, 1,4-divinyloxybutane, 1-vinyloxy-4-ethoxybutane or mixtures thereof. Very particular preference is given to using 1,4-diethoxy-butane, 1,4-divinyloxy-butane or mixtures thereof.
The cocatalysts to be used in the process of the invention are obtainable by the following syntheses:
(a) 4-Alkenyloxy-1-butanols and 1,4-dialkenyloxybutanes are formed by reacting 1,4-butanediol with acetylenes in the presence of a basic catalyst and separating the product by distillation. In this way it is possible for example to obtain 4-vinyloxy-1-butanol and 1,4-divinyloxybutane by reacting 1,4-butanediol with ethyne and distillative workup.
(b) 4-Alkoxy-1-butanols and 1,4-dialkoxybutanes are prepared by catalytic hydrogenation of the 4-alkenyloxy-1-butanols and 1,4-dialkenyloxybutanes obtained according to (a). Suitable hydrogenation catalysts are known to one skilled in the art. It is possible to use, for example, noble metal powders, mohr or black, supported hydrogenating metals, for example noble metals or copper on charcoal or oxidic carrier materials. 1,4-Diethoxybutane can thus be obtained by hydrogenating 1,4-divinyloxybutane.
Alternatively, the 4-alkoxy-1-butanols and 1,4-dialkoxybutanes are also obtainable by etherifying 1,4-butanediol with the corresponding alkanols according to etherification methods known to one skilled in the art.
(c) 1-Alkenyloxy-4-alkoxybutanes are obtained by react
Böttcher Arnd
Lorenz Rudolf Erich
Pinkos Rolf
Preiss Thomas
BASF - Aktiengesellschaft
Keil & Weinkauf
Kumar Shailendra
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