Distillation: processes – separatory – Distilling to separate or remove only water – From organic compound
Patent
1994-06-07
1996-06-04
Manoharan, Virginia
Distillation: processes, separatory
Distilling to separate or remove only water
From organic compound
203 33, 203 36, 203 37, 203 38, 203 92, 203 95, 560218, B01D 334, B01D 338, C07C 6748
Patent
active
055229719
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
This invention relates to an improvement in the recovery, in the pure state, of substantially neutral low-volatile organic components prone to undergo polymerization and/or gelling, which components comprise reactive olefinic double bonds. More particularly, the invention is intended to provide the isolation in the pure state of those components, the purification of which is not possible or not readily possible by means of a distillation. The problems to be solved by the invention are described hereinbelow by way of example for the substance class of polyolacrylic acid esters. However, it will be readily intelligible to one skilled in the art that the area of application of the invention is not restricted to this particular class of substances. The corresponding esters of crotonic acid are another example.
STATEMENT OF RELATED ART
For producing polyol(meth)acrylic acid esters, polyfunctional alcohols are esterified with acrylic acid and/or methacrylic acid--hereinbelow designated as (meth)acrylic acid--in the presence of suitable catalysts and inhibitors and in the presence of an entraining agent, for example toluene and/or xylene. Inherent disadvantages are the concomitant use of solvents and/or entraining agents and the need of removing excessive (meth)acrylic acid and the acidic catalyst--conventionally p-toluenesulfonic acid--from the crude product by washing with an alkaline medium.
The publications DE-A1-38 43 854,DE-A1-38 43 938,DE-A1-38 43 930 and DE-A1-38 43 843 describe possible improvements in the preparation of such polyfunctional (meth)acrylic acid esters without using any solvents. In addition to this option of absolutely avoiding the use of solvents, there is another process advantage in that acidic substances present in the crude reaction mixture--for example residual amounts of the (meth)acrylic acid, acidic catalysts and/or inhibitors exhibiting an acidic reaction--can be removed without a step of washing, by a so-called dry neutralization. Details of this process modification are described in DE-A1-39 39 162 and DE-A1-39 39 163.
In the process described, for example, in the first mentioned printed publication, under optimized conditions, the crude reaction product having an acid value of about 40--caused by an excess of acrylic acid, p-toluenesulfonic acid and phenolic production inhibitors, especially di-tert-butylhydroquinone--is admixed with a twofold molar excess, relative to the acid value, of (anhydrous) calcium hydroxide at 80.degree. C. The resulting mixture is allowed to react for about 1 hour, and then the water of neutralization is stripped off, and calcium salts of said acidic components are removed frown the reaction mixture by filtration. This process has the advantages of that the acidic components are almost completely removed, the product after filtration has a good color, and all of the by-products are concentrated in the filter cake.
The disadvantages of this embodiment of the dry neutralization reside in the relatively long duration of the filtration and in a comparably high loss of valuable product in the filter cake. Thus, the process described in DE-A1-39 39 162 may require filtration periods of several hours in a 1 kg laboratory test (usually from 2 to 4 hours), and the product losses may amount to between 10 and 15% by weight.
DESCRIPTION OF THE INVENTION
Object of the Invention
It is the object of the present invention to substantially reduce the deficiencies shown here of the dry neutralization, without basically having to compromise the advantages of the described type of process. More specifically, the teaching of the invention is to optimize the process for preparing the reaction products of the type described as undistillable and prone to gelling, so that with short filtration times and low expenditure on filters lower amounts of filter cakes are obtained and, consequently, low losses of valuable materials occur.
SUMMARY OF THE INVENTION
The teaching according to the invention is based on the finding that the neutralizing
REFERENCES:
patent: 5159106 (1992-10-01), Ritter et al.
patent: 5198574 (1993-03-01), Ritter et al.
patent: 5207874 (1993-05-01), Hess et al.
patent: 5210281 (1993-05-01), Ritter et al.
patent: 5225049 (1993-07-01), Barmentlo et al.
Ortanderl Stefanie
Ritter Wolfgang
Grandmaison Real J.
Henkel Kommanditgesellschaft auf Aktien
Jaeschke Wayne C.
Manoharan Virginia
Szoke Ernest G.
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