Polymerization of aromatic aldehydes, 8. Cationic copolymerization of 2,2′‐biphenyldicarbaldehyde with styrene

Abstract

Cationic copolymerizations of 2,2'-biphenyldicarbaldehyde (11) (diphenaldehyde) with styrene were carried out with BF30(CzHs)z in dichloromethane. The copolymers were white powders (MW : 6000-7 000) and soluble in common organic solvents. The monomer reactivity ratios (BF30(CzHs)z, CHzC12, -78'C) were: rl (11) = 0,13 & 0,07; ~2 (styrene) = 0,70 i 0,05. The IR data showed the presence of pendant aldehyde groups corresponding to 20-40y0 of I1 units. The content of pendant aldehyde groups increased with the content of I1 in the copolymer. Therefore, the intramolecular cyclization of I1 must occur in competition with the monomer addition during the propagation step. Recovery of the bis-hydrazone of I1 on acid hydrolysis of the copolymer was consistent with the monomer sequence estimated from the reactivity ratio. Attempted homopolymerization of I1 was not successful. ZUSAMMENFASSUNG:Die kationische Copolymerisation von 2,2'-Biphenyl-dicarbaldehyd (11) mit Styrol wurde in Dichlormethan als Losungsmittel und mit BF3-atherat als Initiator untersucht. Die erhaltenen Copolymeren (MW: 6000-7000) waren weil3e Pulver, die sich in den iiblichen organischen Losungsmitteln losten. Die Copolymerisationsparameter (BF3-atherat, CH2C12, -78°C) betrugen: rl (11) = 0,13 & 0,07 und r2 (Styrol) = 0,70 0,05. GemaD IR-Spektrum enthalten die Copolymeren nur 20-40 yo freie Aldehydgruppen, was durch eine intramolekulare Cyclisierung von I1 wahrend des Wachstumsschrittes erklart werden kann.Diese Annahme wird durch chemische Reaktionen (Hydrazonbildung) gestiitzt. Eine Homopolymerisation von I1 gelang nicht.

Polymerization of aromatic aldehydes, 11. Polymerization of 3‐(o‐formylphenyl)propionaldehyde and o‐phenylenediacetaldehyde

“…C22H17NsOs (521,4) Calc. C 50,58 H 3,47 N 21,44 Found C 51,37 H 3,74 N 21,36 o-Phenylenediacetaldehyde (5): 5 was prepared by oxidation of trans-1,2,3,4-tetrahydronaphthalene-2,3-diol with an excess (10%) of lead tetraacetate in benzene, according to the procedure of Huisgen and Saschturka'! The crude product was purified by distillation: bpo.oo6 78-79"C, mp 31,5-32,5"C (lit.7): mp 25-35°C); yield 38%.…”

“…The polymer obtained with the Ziegler catalyst showed similar IR characteristics. (5) In Tab. 2 are summarized the results of the cationic polymerization performed with BF3.0(C2H5)2 catalyst at 20 to -78°C.…”