Patent GB-1119914-A (GB)
Title: Improvements in "equilibration of poly-(1,4-phenylene ethers)"
Inventor: COOPER GLEN DALE
IPC: C07F7/18
Filed: 1967-04-05
Abstract: The invention relates to a process of equilibrating poly-(1,4-phenylene ethers) which comprises reacting (1) a poly-(1,4-phenylene ether) having the formula <FORM:1119914/C2/1> where n is an integer and is at least 10, R is an alkyl radical containing 1 to 8 carbon atoms, free of an aliphatic, tertiary a -carbon atom, or phenyl and R1 is the same as R and in addition, biphenylyl, terphenylyl or naphthyl and (2) a phenol having the formulae (A), (B) or (C):  <FORM:1119914/C2/2> where m is O or 1, R2 is hydrogen, an alkyl radical having 1 to 8 carbons free of an aliphatic tertiary a -carbon atom, phenyl or halogen; R3 is the same as R2 and, in addition, hydroxyl; R4 is an alkyl radical having 1 to 8 carbon atoms, an alkoxy radical having 1 to 8 carbon atoms, an acyl radical having 1 to 8 carbon atoms, hydrogen or phenyl, and in addition, R4 is halogen when each R2 on the same benzene ring as R4 is hydrogen or halogen, and R5 is hydrogen, methyl, ethyl or phenyl, said reaction being initiated by a free phenoxy radical derived from the polyphenylene ether of (1), and/or a free phenoxy radical derived from the phenol of (2), the reaction being carried out at a temperature in the range from room temperature up to the reflux temperature of the reaction mixture.  After the reaction any residual polymer is separated and the remaining oligomeric products are reacted with a mono-functional silylating agent, an acyl halide or an acyl anhydride, and the derivatives of the oligomers separated.  The invention also relates to compounds of the general formula <FORM:1119914/C2/3> where Z is: <FORM:1119914/C2/4> In an example poly-(2,6-dimethyl-1,4-phenylene ether) is equilibrated with 2,6-dimethyl-phenol using 3,31,5,51 - tetramethyl - 4,41 - diphenoquinone to produce the phenoxy radical initiator.  Unreacted starting material and reduction product are removed and any polymer precipitated.  The filtrate was concentrated and treated with bis(trimethylsilyl) acetamide to convert the oligomers to their trimethylsilyl ethers. Silyl ethers may also be prepared by the use of trimethylsilylchloride in place of the bis(trimethylsilyl) acetamide, and a hydrogen chloride acceptor.  On fractional distillation three fractions have the formula:  <FORM:1119914/C2/5> and the corresponding tri- and tetra-compounds were obtained.  The corresponding phenols were obtained by treating with methanol.  In another example instead of the acetamide of the previous example, acetic anhydride is used and on distillation three fractions having the formula <FORM:1119914/C2/6> and the corresponding tri- and tetra-compounds were obtained.  In another example poly-(2,6-dimethyl - 1,4 - phenylene ether), p - bromo-phenol phenol and benzoyl peroxide were heated to reflux and bis(trimethylsilyl) acetamide added and heating continued at reflux and on fractional distillation two fractions having the formul, <FORM:1119914/C2/7> <FORM:1119914/C2/8> are obtained.  Hydrolysis of these silyl ethers produced 4 - (4 - bromophenoxy) - 2,6, - dimethylphenol and 4 - [4 - (4 - bromophenoxy) - 2,6 -dimethylphenoxy] - 2,6 - dimethyl - phenol. In another example to a heated mixture of 3,31,5,51-tetramethyl-4,41-biphenol, 3,31,5,51-tetramethyl -4,41-diphenoquinone and benzene was added poly - (2,6 - dimethyl - 1,4 - phenylene ether).  After heating for 16 hours at reflux, bis(trimethylsilyl)-acetamide, was added and after 2 hours the mixture was fractionally distilled to obtain the ether of the dimer of the formula <FORM:1119914/C2/9> Hydrolysis of this fraction produced the compound of the formula <FORM:1119914/C2/10> In another example 4,41-isopropylidenediphenol, poly - (2,6 - dimethyl - 1,4 - phenylene ether), 3,31,5,51 - tetramethyl - 4,41 - diphenoquinone in benzene was heated for two hours at 80 DEG  C. and bis(trimethyl-silyl)acetamide was then added and after further heating the mixture was fractionally distilled and bis(trimethylsilyl) ether of 4,41-isopropylidenephenol of the general formula <FORM:1119914/C2/11> was obtained.  On treating with methanol the corresponding phenol of the formula <FORM:1119914/C2/12> was obtained.