Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From phenol – phenol ether – or inorganic phenolate
Reexamination Certificate
2000-09-06
2001-09-18
Boykin, Terressa M. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From phenol, phenol ether, or inorganic phenolate
Reexamination Certificate
active
06291630
ABSTRACT:
The present invention relates to a catalyst formulation, which is liquid at room temperature, of tetraphenylphosphonium phenolate and phenol and the use thereof as a transesterification catalyst, in particular for the solvent-free preparation of thermoplastic polycarbonates.
The preparation of phosphonium phenolate is known from DE-OS 196 35 656 and German Patent Application P 197 27 351.3. It is known from U.S. Pat. No. 3,442,854, inter alia, that phosphonium phenolates, optionally co-using alkali metal/alkaline earth metal compounds, are particularly suitable as catalysts for esterification and for transesterification, in particular for the preparation of polycarbonates by the melt transesterification process. Since metering in the catalyst as a solid presents technical difficulties, it is desirable to meter in the catalyst in liquid form. For example, the catalyst can be dissolved in liquid phenol, i.e. at temperatures above 45° C., in general at approx. 60° C., and can be fed to the process as a solution. This requires a heated reservoir and therefore additional technical expenditure. It is furthermore known from J. Org. Chem. 32 (1967) 1060 that phosphonium phenolates are unstable to heat, so that thermal predamage, in particular by a long residence of the catalyst solution in the heated reservoir, cannot be ruled out. Metering from a mixture, which is liquid at room temperature, of phenol and water (90 wt. %: 10 wt. %) offers another possibility. A disadvantage here is that water is introduced into the process as an additional substance. Liebigs Ann. Chem. vol. 634 (1960) 1 moreover describes the alkaline decomposition of quaternary phosphonium salts to triphenylphosphine oxide. According to our own investigations, small amounts of water at higyh temperatures also have the effect of cleavage of tetraphenylphosphonium phenolate (TPP-P) to triphenylphosphane oxide.
The object of the present invention was therefore to provide a simple possibility for liquid metering of tetraphenylphosphonium phenolate. It has now been found that a mixture of TPP-P, or the adduct of TPP-P with 2 molecules of phenol, called TPP-P*2PhOH in the following, with phenol at a composition of 28 to 45 wt. % TPP-P (or 40-65 wt. % TPP-P*2PhOH)-and correspondingly 72 to 55 wt. % (or 60 to 35 wt. %) phenol is liquid at room temperature. This allows addition of the catalyst in the liquid state without foreign substances or additives and without preliminary exposure of the catalyst to heat.
The liquid formulation obtained according to the invention of tetraphenylphosphonium phenolate can be used in a manner known per se as a catalyst for the preparation of aromatic polycarbonates (see, for example, U.S. Pat. No. 3,442,854). According to the melt transesterification process disclosed there, for example, aromatic polycarbonates are prepared from aromatic diphenols, carbonic acid diaryl esters and optionally branching agents and/or monophenols.
The phosphonium phenolates prepared according to the invention can be employed as transesterification catalysts in amounts of 10
−1
mol to 10
−8
mol, preferably in amounts of 10
−3
mol to 10
−7
mol, per mol of diphenol.
Further details of the melt transesterification process are described in the literature, (see, for example, Hermann Schnell, Chemistry and Physics of Polycarbonates, Polymer Reviews, vol. 9, 1964, pages 44 to 51, DE-AS 1 031 512, U.S. Pat. No. 3,022,272, U.S. Pat. No. 5,340,905 and U.S. Pat. No. 5 399 659).
The thermoplastic polycarbonates prepared with the liquid formulation according to the invention of TPP-P are solvent free, have a light intrinsic colour and are largely free from undesirable defects in the polycarbonate. In the context of the process according to the invention, largely free from undesirable defects in the polycarbonate means that the content of branching agents of the formula (I)
where
X=C
1
-C
9
-alkylidene or cycloalkylidene, S or a single bond and
(R)
n
=in each case independently of one another COOH, CH
3
, Cl or Br, where several different (R)
n
can also occur on one phenyl ring
n=0,1,2 or 3,
in the polycarbonate does not exceed a value of 300 ppm according to total hydrolysis and HPLC determination.
REFERENCES:
patent: 3022272 (1962-02-01), Schnell et al.
patent: 3442854 (1969-05-01), Curtius
patent: 4302574 (1981-11-01), Doorakian
patent: 5340905 (1994-08-01), Kühling et al.
patent: 5399659 (1995-03-01), Kühling et al.
patent: 1031512 (1958-06-01), None
patent: 0798329 (1997-10-01), None
patent: 0826692 (1998-03-01), None
patent: 9900395 (1999-01-01), None
Polymer Reviews, vol. 9, (month unavailable), 1964, pp. 44-51, Hermann Schnell, “Chemistry And Physics of Polycarbonates”.
Liebigs Ann. Chem., vol. 634, (month unavailable), 1960, p. 1, von Hellmut Hoffmann, “Zur Kinetick Der Alkalischen Spaltung Quartärer Phosphoniumsalze”.
J. Org. Chem., 32, (month unavailable), 1967, pp. 1060-1063, H. R. Hays, et al, “Reaction of Tetraalkylphosphoniumn Salts with Anhydrous Sodium Hydroxide”.
Konig Annett
Prein Michael
Bayer Aktiengesellschaft
Boykin Terressa M.
Gil Joseph C.
Preis Aron
LandOfFree
Method for producing a liquid formulation of... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for producing a liquid formulation of..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for producing a liquid formulation of... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2484952