Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From phenol – phenol ether – or inorganic phenolate
Patent
1982-01-18
1983-08-30
Lee, Lester L.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From phenol, phenol ether, or inorganic phenolate
422225, 422232, 526 65, 526 66, 528179, 528182, 528194, C08G 6318, C08G 6324
Patent
active
044018037
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The invention relates to a process for the preparation of aromatic polyesters by polycondensation of diphenols with chlorides of aromatic dicarboxylic acids, such as isophthalic acid and/or terephthalic acid, according to the two-phase interfacial polycondensation process, and to an apparatus for carrying out this process.
STATE OF THE ART
In a two-phase interfacial polycondensation process described in U.S. Pat. No. 3,216,970, a fine dispersion is prepared from the aqueous phase composed of a solution of the diphenol, alkali metal hydroxide in the stoichiometric ratio or in a slight excess in order to form the diphenolate and a phase transfer catalyst in water and, if appropriate, an organic solvent as a solubilizer with the organic-liquid phase composed of a solution of the acid chloride in a chlorinated solvent, the diphenolate which has been transferred into the organic-liquid phase with the aid of the phase transfer catalyst undergoing a polycondensation reaction with the acid chloride to form the polyester and the resulting polyester being dissolved in the organic phase. In the examples described in this U.S. patent specification, the viscosity reached by the synthesized polyesters is rather low. This is the case especially if these are polyesters, for the synthesis of which diphenolates are used which have a central carbon atom of such a type that free rotation of the groups bonded to this carbon atom is hindered.
DESCRIPTION OF THE INVENTION
It is now the object of the invention to indicate a process for the preparation of polyesters of the abovementioned type, wherein under otherwise identical conditions a higher intrinsic viscosity of the synthesized polyester is obtained than in the known processes.
The object of the invention is achieved, according to the invention, by a process which comprises circulating the reaction mixture, which is prepared as a dispersion of the aqueous phase and of the organic-liquid phase, through a dispersing device and continuously introducing the acid chloride, which is to be fed in and which is dissolved in a largely anhydrous chlorinated solvent, into this circulation at a point which, in the direction of flow, is upstream of the dispersing device. In this process, it is advantageous to prepare a dispersion from the aqueous phase to be fed in and a part quantity of the solvent to be fed in, of the organic-liquid phase, and to maintain this dispersion into which the acid chloride solution to be fed in is then introduced. The part quantity of the solvent, to be fed in, of the organic-liquid phase, which part quantity serves for preparing a dispersion of the reaction mixture, does not contain any acid chloride and--in contrast to the solvent used for dissolving the acid chloride to be introduced--therefore does not need to meet any stringent purity requirements, in particular with respect to being largely anhydrous.
According to an advantageous embodiment of the invention, the process according to the invention comprises, for preparing the dispersion from the aqueous phase and a part quantity of the chlorinated solvent to be fed in, of the organic-liquid phase, passing the mixture of these two components through the dispersing device.
According to another advantageous embodiment of the invention, the reaction mixture is passed in the dispersing device through one or more mixing stages in series, the mixture being divided in each mixing stage into several part streams, the flow boundaries of the part streams carrying out motions transversely to their main directions of flow at mean velocities greater than 5 m/second and the part streams passing to a mixing chamber which is provided with at least one outlet channel and in which the kinetic energy of the mixture is reduced to a value which is low compared with its maximum value, the zones of the mixture flowing in the mixing chamber being subjected to flow conditions which vary in an at least almost periodic manner.
It is also an object of the invention to indicate an advantageous apparatus for car
REFERENCES:
patent: 3216970 (1965-11-01), Conix
patent: 3351624 (1967-11-01), Conix
patent: 3498950 (1970-03-01), Shatz et al.
patent: 4201855 (1980-05-01), Segal
patent: 4362858 (1982-12-01), Shimizu et al.
Isovolta Osterreiche Isolierstoffwerk Aktiengesellschaft
Lee Lester L.
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