Organic compounds -- part of the class 532-570 series – Organic compounds – Carboxylic acid esters
Reexamination Certificate
1995-05-08
2002-11-19
Jones, Dwayne C. (Department: 1614)
Organic compounds -- part of the class 532-570 series
Organic compounds
Carboxylic acid esters
C560S098000, C568S863000, C568S882000, C568S883000
Reexamination Certificate
active
06482972
ABSTRACT:
The invention relates to mixtures of isomeric nonanols and decanols, a process for their preparation, the phthalic esters obtained from these alcohols mixtures, and the use of these esters as plasticizers.
BACKGROUND OF THE INVENTION
Esters of phthalic acid have wide application as plasticizers, in particular for polyvinyl chloride. The alcohol components are principally primary alcohols having from 8 to 10 carbon atoms, the most important among them presently being 2-ethylhexanol. Phthalic esters of short-chain alcohols give plasticizers with good gelling powder; however, their higher volatility is a disadvantage. In comparison, long-chain esters gel more slowly but have poorer cold resistance.
The properties of the phthalic ester plasticizers are affected, not only by the size of the alcohol molecule, but also by the branching of the hydrocarbon chain. Thus, alcohols with little branching give ester plasticizers of high cold flexibility. Largely linear alcohols having from 9 to 10 carbon atoms in the molecule are therefore becoming increasingly important as alcohol components. A prerequisite for their use is that they are available in large quantities and at advantageous prices.
In German Patent 28 55 421, the plasticizers used are phthalates of C
9
-alcohols, which are obtained by the oxo-reaction of C-
8
-olefins, hydrogenation of the reaction product, and esterification of the C
9
-alcohols with phthalic anhydride. From 3% to 20% by weight of the starting olefins is said to have an isobutane skeleton in each molecular chain, less than 3% by weight of the olefins should contain quaternary carbon, and more than 90% by weight of the total amount of olefins is said to be present as n-octenes, monomethylheptenes, and dimethylhexenes. Furthermore, the weight ratio of the total amount of the n-octenes and monomethylheptenes to the dimethylhexenes is said to be more than 0.8.
Phthalic esters based on C
10
-alcohols are the subject of the European Patent Application 3 66 089. The C
10
-alcohols are used in the form of a mixture which is obtained by hydroformylation of a butene fraction, aldol condensation of the aldehyde mixture thus obtained, and subsequent hydrogenation. According to the process description, the hydroformylation step is not subject to any limitations. The catalysts used may be cobalt as well as rhodium; the addition of an organic compound of trivalent phosphorus is not excluded.
Another route to obtaining didecylphthalate mixtures is described in European Patent Application 4 24 767. The preparation of the esters is carried out in a multistage process by dimerization of butene mixtures, hydroformylation and hydrogenation of the resulting octene mixture to give a nonanol mixture, dehydration of the nonanol mixture to form a nonene mixture, and hydroformylation and hydrogenation of the nonene mixture to form the desired decanol mixture.
According to EP-B-52 999, plasticizer alcohols are prepared from a mixture of propylene and butenes in a molar ratio of 2:1 to 1:3. The olefins are jointly converted by the oxo reaction to a mixture of butyl and amyl aldehydes which is subjected to an aldol condensation. The resulting condensation products are subsequently hydrogenated to saturated alcohols.
The known alcohols or alcohol mixtures used for the preparation of plasticizers do not meet all the economic and technical requirements which are demanded of products produced on an industrial scale, because the starting materials are not available in sufficient quantity, the prices are too high, the conversion of the starting materials into the alcohols necessitates extremely costly processes, and/or the quality of the plasticizers prepared from the alcohols leaves much to be desired.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to develop suitable alcohol or alcohol mixtures for the preparation of high-quality plasticizers. They should be obtained from economically available raw materials in a technically simple manner.
This object is achieved by mixtures of isomeric nonanols and decanols which are obtained by joint aldol condensation of n-butanal and pentanals in a molar ratio of from 1:2 to 1:10. The pentanal mixtures comprise 60% to 90% by weight of n-pentanal, 10% to 40% by weight of 2-methylbutanal and up to 1% by weight of 3-methylbutanal. The aldol condensation product is then hydrogenated to form the saturated alcohols, and the components boiling at lower temperatures than the nonanols and decanols are removed from the reaction mixture.
It is preferable to use mixtures of isomeric nonanols and decanols which are prepared from n-butanal and pentanals which contain from 65% to 80% by weight of n-pentanal, 20% to 35% by eight of 2-methylbutanal, and up to 1% by weight of 3-methylbutanal. The alcohol mixtures are obtained by aldol condensation of a mixture containing n-butanal and pentanals in a molar ratio of 1:2 to 1:10, subsequent hydrogenation of the aldol condensation product, and removal of the 2-ethylhexanol formed. The source of the aldehydes is immaterial; the criteria are chiefly economic. To promote the formation of alcohols with little branching, the aldehydes must have the carbonyl group on the terminal carbon atom and, in the case of the pentanals, be at least substantially unbranched. Therefore, the pentanals used are mixtures containing from 60% to 90% by weight of n-pentanal, from 10 to 40% by weight of 2-methylbutanal, and up to 1% by weight of 3-methylbutanal.
Preferred starting materials are aldehydes prepared by hydroformylation (oxo process) of propylene or butenes. The required olefins are available in industrial quantities. Propylene is obtained as byproduct in ethylene production by pyrolysis of hydrocarbon mixtures in the presence of water vapor and also in some refinery processes, particularly the catalytic cracking of petroleum fractions.
Mixtures containing butene-1 and butene-2 are also necessarily obtained in considerable quantities as refinery byproducts in the production of automotive fuels and in the production of ethylene by thermal cracking of higher hydrocarbons. They are isolated from the C
4
cracking fractions of the pyrolysis product by extraction of the butadiene-1,3 by a selective solvent, and subsequent removal of the isobutene preferably by conversion into methyl t-butyl ether. Instead of extracting the butadiene-1,3, it can also be partly hydrogenated to butenes in the C
4
cracking fraction. The pyrolysis product freed of butadiene-1,3 is identified as raffinate I. If the isobutene has also been removed, it is referred to as raffinate II. This butene-1/butene-2 mixture is particularly suitable for further processing into decanols.
Basically, all current commercial hydroformylation processes are suitable for converting the olefins into aldehydes. Thus, the process can be carried out in the presence of cobalt or rhodium catalysts at pressures of 10 to 35 MPa and at temperatures of 120° to 180° C.; in the presence of cobalt/phosphine catalysts at pressures of from 5 to 10 MPa; or in the presence of rhodium catalysts which are modified by phosphine at temperatures of 60° to 150° C. and pressures of 1 to 8 MPa. In the last-described variant of the hydroformylation reaction, the catalyst may be homogeneously dissolved in—or form a separate phase from—the reaction mixture.
To prepare the aldehydes, propylene and the butenes may be reacted together, but preferably separately. It has proven particularly valuable to carry out the hydroformylation as a heterogeneous reaction in a two-phase system, a reaction which is described, for example, in DE-C-26 27 354. This embodiment of the oxo process ensures that olefins having their double bonds at a terminal carbon atom form largely n-aldehydes and that isomerization of the olefins by migration of the double bond during the reaction is essentially avoided.
The two-phase process is characterized by the presence of an organic phase, which contains the starting olefins and the reaction product, and an aqueous phase, in which the catalyst is dissolved. Catalysts u
Bahrmann Helmut
Fenske Wilfried
Greb Wolfgang
Heymanns Peter
Lappe Peter
Bierman, Muserlian and Lucas
Hoechst Aktiengesellschaft
Jones Dwayne C.
LandOfFree
Isomeric nonanols and decanols, their preparation, phthalic... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Isomeric nonanols and decanols, their preparation, phthalic..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Isomeric nonanols and decanols, their preparation, phthalic... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2950680