Cresol polycondensation

Novel l,3,4-oxadia2ole-containing polya2omethines have been synthesi2ed by the polycondensation of diamines, 2,5-bis(y -aminophenyl)-l,3,4-oxadia2ole and 2,5-bis(/)-aminophenyl)-l,3,4-oxadia2ole with aromatic dialdehydes, isophthaldehyde, and terephthalaldehyde (example follows), in y -cresol at 20°C (54). 

The first polyimine was reported by Adams and coworkers [182] from terephthalaldehyde and benzidine and dianisidine. Between 1950 and 1959 Marval and coworkers [174-176] reported a number of polyimines. Suematsu and coworkers [170] reported the first successful synthesis of high molecular weight fully aromatic polyimines by solution polycondensation method using w-cresol as reaction medium. 

Room-temperature solution polycondensation is used for the preparation of hexafluoroisopropylidene-unit-containing poly(azomethine)s. At the end of the reaction, the water liberated by the reaction is thoroughly taken off as an azeotrope by vacuum distillation to allow the reaction to go to completion. Among DMF, DMSO, HMPA, NMP, and m-cresol used as reaction solvents, m-cresol yields a polymer with higher reduced viscosity in higher yield. The reaction proceeds rapidly and is essentially completed in 30 min. 

Kaneda et al. synthesized [61] a series of high molecular weight extended chain copolyimides (XV) by the reaction of PMDA and 3,3, 4,4 -biphenyltetra-carboxylic dianhydride (PPDA) with 3,3 -dimethyl-4,4 -diaminobiphenyl. Solvents used for the one-step synthesis to the fully cyclized imide structure were phenol, p-chlorophenol, m-cresol, p-cresol and 2,4-dicholorophenol. The polycondensations were performed at 180°C for 2h with a monomer concentration of 6% by weight and p-hydroxybenzoic acid used as a catalytic accelerator. A maximum of 50 mol % of PMDA could be used before the copolymer precipitated from solution. Reconstituted copolymers as isotropic dopes (8-10% by weight) in p-chlorophenol were dry-jet wet spun between 80 and 100 °C [62]. 

High-temperature solution polycondensation in w-cresol using isoquinoline as catalyst (procedure 3). 

Syntheses of phenoxy-substituted polynaphthylimides and polyperyleneimides were carried out in accordance with Scheme 5.4 [37, 38]. All polycondensation reactions were carried out under high-temperature solution polycondensation conditions in phenolic solvents (w-cresol, m- or p-chlorophenols) using benzimidazole and benzoic acid as catalysts. All the reactions proceeded homogeneously and led to the formation of deeply coloured polymers. General properties of the polymers are listed in Table 5.6. 

Diamino-6-(N-phthalimido)-toluene was reacted with aromatic tetracarboxylic acids, 3,3, 4,4 -tetracarboxydiphenyl ether, 3,3, 4,4 -tetracarboxybenzophenone and dianhydrides, dianhydride 6F and dianhydride A, using high-temperature polycondensation in w-cresol with quinoline as a catalyst (Scheme 5.8). 

The rate is slower in basic aprotic amide solvents, and faster in acidic solvents such as / -cresol. In general, the imidization reaction has been shown to be catalyzed by acid (14,32,33). Thermal imidization of poly(amic acid)s is catalyzed by tertiary amines (34). High temperature solution polymerization in -cresol is often performed in the presence of high boiling tertiary amines such as quinoline as catalyst. Dialkylaminopyridines and other tertiary amines are effective catalysts in neutral solvents such as dichlorobenzene (35). Alkali metal and zinc salts of carboxylic acids (36) and salts of certain organophosphorus compounds (37) are also very efficient catalysts in one-step polycondensation of polyimides. 

Another example of the use of deoxidation of oxygen-containing compounds for their structural analysis was given by Wi jnands et al.68, who investigated the structure of novolaks, prepared by polycondensation of formaldehyde with phenol, />-cresol and w-cresol. The novolaks were transformed into saturated hydrocarbon mixtures by direct hydrogenation. Ultimate analysis of the hydrocarbons confirmed the linear structure of the novolaks ... 

Polycondensates were prepared from pyrocatechol, o-cresol, p-cresol, mixtures of the latter with 2,4-dimethylphenol,2-tert-butyl-4-methylphenol, di-scc-butyl-phenol or other monoalkylphenols and their mixtures with dialkylphenols or alkoxyphenols. 

Novolaks 127 formed from p-cresol and 2-terr-butyl-4-methylphenol were studied in some details [159], Phenolic groups present in 127 are not equivalent in the reactivity with RO2. A good antioxidant efficiency was observed in PS and poly (ethylene-co-propylene), even with polycondensates having n > 15. Polycondensate 128 is an example of AO which may be used in contact with food [160]. 

Reported values for the activation enei of the amidation reaction vary. For the melt poly condensation of aminoundecanoic acid the activation energy was found to be [87] 11 kcal mole for the polycondensation of the same acid as a 30% solution in m-cresol, the reported [92] activation energy is 31 kcal mole". The activation energy of the second-order melt polycondensation of p-aminophenylalkanoic acids was reported [93] to be between 17 emd 19 kcal mole". ... 

The polyimides derived from the dianhydrides had high Tg s of 238 to 466 °C and they were soluble in chlorinated hydrocarbon solvents. Because of their solubility, copolyimides containing the following acetylene substituted diamine monomere were readily prepared by homogeneous high temperature solution polycondensation in m-cresol. 

Neckers et al. [16, 17, 18] demonstrated that polyureas with backbone azobenzene groups (70) also underwent a photoviscosity effect when ultraviolet-irradiated. Stille et al. [19] reported that the intrinsic viscosity of polyquinoline (II) with backbone stilbene groups in di-m-cresyl phosphate/m-cresol decreased as much as 24% under ultraviolet light. The decrease was ascribed to the tram to cis isomerization of the stilbene groups. Because of its simplicity the mechanism (3) has been widely applied to other polycondensation or polyaddition polymers. 

Most of the ICs were obtained makinguseofaresistformulation discovered by Suss, namely, diazonaphthoquinone as PAC and novolak resin (Chart 12.1) as polymer matrix [12]. The resolution achieved with this resist formulation was smaller than 500 nm [13]. Novolak is obtained through a polycondensation reaction between formaldehyde and cresols [4,14]. The novolak resin is photochemically inert at 436 and 365 nm, and is easily soluble in basic developers due to its phenolic OH groups, but upon addition of naphthoquinone the dissolution rate decreases dramatically [15,16]. 

Analogously to the procedure described in Refs. [181, 182], polynaphthoylenebenzimidazoles were synthesized by high-temperature catalytic polycondensation in a m-cresol medium i ing benzoic acid as catalyst. 

Similarly to the preparation of polynaphthoylenebenzimidazoles from sulfide-containing bis(naphthalic anhydrides) [92, 107-110], tlw synthesis has been carried out by a high-temperature catalytic polycondensation method in m-cresol using benzoic acid as catalyst. 

These reactions have b n carried out both under traditional conditions, i.e. high-temperature polycondensation in m-cresol and application of benzoic acid as catalyst [99] and in a ries of other solvents [190] - mixtures of m-cresol and polyphosphoric acid, m-cresol and di-m-cresyl phosphate, m-cresol... 

Synthesis of these polynaphthoylenebenzimidazoles was carried out by the high temperature polycondensation technique in m-cresol using benzoic add as catalyst. All reactions for synthesis of polynaphthoylenebenzimidazoles ran homogeneously and led to well-cyclized high molecular polymers. Some characteristics of polynaphthoylenebenzimidazoles based on a series of aroylene-bis(naphthalic anhydrides) and 3,3, 4,4 -tetraaminodiphenyl oxide are shown in Table 23. 

Synthesis of these polymers was carried out by high-temperature catalytic polycondensation in m-cresol i ing benzoic acid as catalyst Some characteristics of the synth ized polynaphthoylenebenzimidazoles containing organoelement central moieties are tabulated in Table 23. Introduction of diphenylsilyl and hexafluoroisopropyledene groups led only to a quantitative enhancement in solubility of polynaphthoylenebenzimidazoles in phenolic solvents [116,118], while introduction of m-carboranylene groups into macromolecules imparted solubUity in N-MP [117, 118]. 

Synthesis, under microwave irradiation conditions, of polyamides containing azobenzene units and hydantoin derivatives in the main chains has recently been proposed by Faghihi et al. [55]. Polycondensation of 4,4 -azodibenzoyl chloride with eight 5,5-disubstituted hydantoin moieties has been achieved in the presence of a small amount of o-cresol (Scheme 14.26). The polycondensations were performed in 8 min, in a domestic microwave oven, in a porcelain dish in which 1.0 mmol diacid chloride was mixed with an equimolar amount of diol in the presence of small amounts of o-cresol. The polymerization proceeded rapidly, compared with the bulk reactions under conventional conditions (8 min compared with 1 h), producing a series of polyamides in high yield and inherent viscosity between 0.35 to 0.60 dL g h... 

A limited number of reports have appeared in the literature showing the use of water as a solvent for the microwave-promoted synthesis of thermoplastics. An example is the synthesis of water-borne polyimides using the standard polycondensation reaction of a dianhydride with a diamine (Seheme 3.1). In a scientific microwave unit, polymers with high molecular weights (Af up to 35.460 g/mol) were obtained within 22 min of heating using a one-pot two-step procedure. The dianhydride was first hydrolyzed in water to obtain the corresponding tetracarboxylic acid. This was then condensed with the diamine. The obtained polymers were completely comparable in their chemical and thermal properties to those obtained by conventional polymerization in m-cresol as solvent. 

Alternating copolyimides soluble in m-cresol and having high viscosity characteristics ([q] = 0.50-0.88 dl/g) were obtained on the basis of a perylene-carboximide-containing diamine and various aromatic dianhydrides [7]. The polycondensation process proceeded at 200 °C in m-cresol under homogeneous conditions in the presence of a catalyst (isoquinoline) according to Scheme 1.4. 

The PPI, XI-XIV and XVI (Table 1.3) were prepared by polycondensation in m-cresol using catalysts (benzoic acid and isoquinoline) (Scheme 1.8). 

When the polycondensation process was carried out in organic solvents (nitrobenzene, NMP, and m-cresol) at 180-210 C and an effective catalyst (benzoic acid) was used, PNI having high viscosity characteristics and exhibiting film-forming properties were synthesised [3-36]. 

Polycondensation of DNTA with l,3-bis[4 (4"-aminophenoxy)cumyl]benzene in m-cresol yielded PNI of the Figure 1.6 [42] ... 

Starting from 4,4 -diaminodiphenyl ether oxide and various dianhydrides of oxyarylene-and thioarylene-bisfnaphthalic acids), PNI of the general formula shown in Figure 1.16 were synthesised [21,70]. The polycondensation reaction proceeded under homogeneous conditions in m-cresol using quinoline or isoquinoline as the catalysts. PNI formed solutions in w-cresol up to a concentration of 15%. 

---