Organic compounds -- part of the class 532-570 series – Organic compounds – Oxygen containing
Reexamination Certificate
2002-12-04
2004-09-21
Kumar, Shailendra (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Oxygen containing
C548S335100
Reexamination Certificate
active
06794546
ABSTRACT:
The present invention relates to a continuous process for the preparation of O—, S— and N-alkenyl compounds by reaction of the corresponding OH, SH or NH compound with an acetylene in the liquid phase in the presence of basic alkali or alkaline earth metal compounds at from 40 to 300° C. and from 0.11 to 5 MPa absolute.
Alkenyl compounds represent an important class of compound with a wide range of applications. Alkenyl ethers, for instance, find use as monomeric building blocks in polymers and copolymers, in coatings, adhesives, printing inks and also in radiation-curable coatings. Further areas of application are the production of intermediates, scent and aroma chemicals, and also pharmaceutical products. Alkenylamides are used as monomers in the production of plastics and coatings. Polyvinylamides are used, for example, as laundry detergent ingredients, as adjuvants in cosmetic and medicinal products and also to stabilize and clarify beers and fruit juices. Polyvinyllactams, in particular polyvinylpyrrolidone polymers, have a wide range of uses and serve, for example, as dispersants for pigments, as laundry detergent ingredients, as adjuvants in cosmetic and medicinal products and also as assistants in textile processing and adhesive technology.
The industrial production of vinyl compounds is carried out in general by reaction of the corresponding active-hydrogen compounds, such as alcohols, amides or amines, with ethyne in the presence of basic catalysts (see Ullmann's Encyclopedia of Industrial Chemistry, 6
th
edition, 2000 Electronic Release, Chapter “VINYL ETHERS—Production” and W. Reppe et al., Justus Liebigs Ann. Chem., 601 (1956), pages 135 to 138). The vinylation can take place in both the liquid phase and the gas phase. Vinylation in the gas phase employs basic heterogeneous catalysts, such as KOH on activated carbon or MgO or CaO. In the liquid phase, the strongly exothermic reaction is generally carried out in the presence of alkali metal hydroxide or alkali metal alkoxide catalysts.
DE-B 1 163 835 describes the batchwise preparation of N-vinyl lactams by vinylation of the corresponding lactam with ethyne in the presence of a basic sodium or potassium catalyst by dissolving ethyne in the liquid lactam and then heating the solution at a pressure of from 70 to 350 kg/cm
2
(6.9 to 34.3 MPa) to the reaction temperature of from 150 to 280° C. The adduced examples report conversions of from 36 to 55% and N-vinyl lactam selectivities (“yield based on reacted lactam”) of from 78 to 95%.
DE-A 3 215 093 discloses a process for the vinylation of 2-pyrrolidone with ethyne in the presence of a basic alkali metal salt catalyst and of a polyoxyalkylene cocatalyst. Suitable polyoxyalkylene compounds are said to be crown ethers (for example 18-crown-6), polyoxyethylene, polyoxypropylene, optionally terminated by alkyl or phenyl groups. In a first step, the basic alkali metal salt catalyst is produced by heating potassium hydroxide with 2-pyrrolidone and the cocatalyst with removal of the water formed in the reaction. The subsequent vinylation is carried out batchwise in an autoclave. Conversions of up to 63% and selectivities of 90% were obtained, which corresponds to a maximum yield of 57%.
U.S. Pat. No. 5,665,889 describes a process for the preparation of N-vinyl-2-pyrrolidone from 2-pyrrolidone and ethyne in the presence of basic alkali metal compounds that uses ether oligomers with hydroxy end groups, such as polytetrahydrofuran, or linear diols with at least 4 carbon atoms, such as 1,4-butanediol, as cocatalysts. The vinylation is carried out at a temperature of 100 to 200° C., a pressure of 7.5 to 30 atm (0.76 to 3 MPa) and a reaction time of several hours. In a first step, the basic alkali metal salt catalyst is produced by heating potassium hydroxide with 2-pyrrolidone and the cocatalyst with removal of the water formed in the reaction. The subsequent vinylation is carried out batchwise in an autoclave. The use of 1,4-butanediol results, even after a reaction time of 4 hours, in a yield of only 77.2%.
DE-A 100 02 469 teaches a process for the alkenylation of tertiary alcohols in the presence of a basic alkali metal compound, wherein the tertiary alcohols are converted to a maximum of 90%, the crude product obtained is extracted with water and the tertiary alkenyl alkyl ethers are recovered from the organic phase. Conduction of the reaction by batchwise, semicontinuous or continuous means is described.
WO 01/46141, WO 01/46139 and DE-A 100 17 222 teach processes for the preparation of N-alkenylamides and alkenyl ethers in the presence of basic alkali metal compounds and a 1,2-diol, a 1,3-diol or a mono- or diether of 1,4-butanediol as cocatalyst. The alkenylation is carried out at a temperature of from 100 to 200° C., an ethyne partial pressure of smaller than 5 MPa and a reaction time of several hours. In a first step, the basic alkali metal catalyst is produced by heating potassium hydroxide with NH-amide or with alcohol and the cocatalyst with removal of the water formed in the reaction. The subsequent vinylation is carried out batchwise in an autoclave. After a reaction time of 12 hours, conversions of up to 96.3% and yields of N-vinylamides of up to 90.5% were obtained from the vinylation of NH-amides and conversions of up to 97.7% and yields of vinyl ethers of up to 90.9% were obtained from the vinylation of alcohols. A variant is also described in which the NH-amide or the alcohol and the ethyne are fed to a continuous loop reactor, where a corresponding amount of the reaction solution is continuously removed.
The customary industrial semicontinuous processes, in which the component to be alkenylated is initially charged together with the basic catalyst and the alkyne is continuously added until the end of the reaction, have the disadvantages of the time-, work- and energy-intensive process steps of filling, heating, pressurizing, cooling, depressurizing and emptying of the reaction apparatus, in particular during the preparation of quantities which require several reaction batches. Furthermore, a greater range of relative concentrations of the reactants and products is present during semicontinuous synthesis, which can lead to a conversion-dependent reaction rate and promotes the formation of undesirable byproducts. These disadvantages result in a lower selectivity and, taking into account the necessary preparation times, also a much lower space-time yield than would be expected on the basis of the chemical reaction rate.
It is an object of the present invention to provide a process for the preparation of O—, S— and N-alkenyl compounds by reaction of the corresponding O, S or N compound with an acetylene, that does not have the above disadvantages, allows the preparation of O—, S— and N-alkenyl compounds with high selectivity, high space-time yield and high productivity in a simple way and only forms small amounts of substantially involatile residues.
We have found that this object is achieved by a continuous process for the preparation of O—, S— and N-alkenyl compounds by reaction of the corresponding OH, SH or NH compound with an acetylene in the liquid phase in the presence of basic alkali or alkaline earth metal compounds at from 40 to 300° C. and from 0.11 to 5 MPa absolute, which comprises continuously feeding the corresponding OH, SH or NH compound and the acetylene and operating at a conversion of the corresponding OH, SH or NH compound of ≧90%.
An essential of the process of the invention is that it is conducted at a conversion of the corresponding OH, SH or NH compound of ≧90%, preferably of ≧92%, particularly preferably of ≧95% and very particularly preferably of ≧97%. The desired conversion at the desired temperature and pressure is achieved by the continuous feeding of OH, SH or NH compound and the acetylene at corresponding rates. The term “continuous feeding” also comprehends fluctuations in the amount added, up to an intermittent addition, as long as the specified ratio of amounts in the reactor is achieved.
The conversion C o
Lorenz Rudolf Erich
Pinkos Rolf
BASF - Aktiengesellschaft
Keil & Weinkauf
Kumar Shailendra
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