Hydroxy Hydroxystyrene

Heating pure TBMS, TBS and TBSS films at 130 C gave no volatile products. Pyrolysis at 725°C gave rise to both deprotection (as determined by the evolution of isobutene and carbon dioxide), and depolymerization to afford the respective monomers, sulfur dioxide, 4-hydroxystyrene, or 4-hydroxy-a-methylstyrene. The compounds, 4-hydroxystyrene and 4-hydroxy-a-methylstyrene, were identified on the basis of their mass spectra, which were consistent with those reported in the literature for these materials (22,23). Additionally, TGA analysis confirmed that all three polymers undergo complete volatilization upon heating to >400 C. 

Poly(4-hydroxystyrene) [I], poly(4-hydroxy-3-methoxystyrene) [II], poly(4-hydroxy-3,5-dimethoxystyrene) [III] and their acetates were synthesized from 4-hydroxybenzaldehyde, vanillin and syringaldehyde (2), which were synthesized as shown in Scheme 1. 

In contrast, a Markovnikov addition of water was reported in the irradiation of a variety of o-hydroxystyrenes, again in aqueous acetonitrile, with the formation of 2-(2-hydroxyphenyl)ethanols. In this case, an intramolecular proton transfer from the excited state of the styrene was envisaged as the first step of the reaction [51]. A similar mechanism was postulated in the photohydratation of m-hydroxy-1,1 -diaryl alkenes that gave the corresponding 1,1-diarylethanols, although direct protonation of the P-carbon by water competed in some cases [52]. 

The homogeneous unimolecular decomposition of o-hydroxy-2-phenvlethyl chloride yielded mainly benzodihydrofuran, HC1 and much less o-hydroxystyrene. The rate was significantly higher than that of phenylethyl chloride and ethyl chloride (Table 28). According to the nature of the product formation and the kinetic data, the OH provided anchimeric assistance in the elimination process. The mechanism proposed is described in equations 87 and 88. 

The t-BOC protection group chemistry has been extended to other aqueous-base soluble polymers such as poly[styrene-co-N-(4-hydroxyphenyl)maleimide], ° poly(styrene-co-maleimide), poly(4-hydroxystyrene sulfone), and poly(4-hydroxy-a-methylstyrene) used in lithographic applications. Even novolac resins have been successfully protected with the t-BOC group,which has resulted in significant reduction of the DUV absorption of these resins. ... 

A very prominent example of this type of resist is a copolymer of 4-hydroxy-styrene with tert-butyl ester-protected 4-hydroxystyrene (TBEST) (XXIX) (see scheme 7.33), developed at IBM and sold under the brand name of APEX-E by the Shipley Company. The synthetic route to copolymer (XXIX) can be through direct copolymerization of 4-hydroxystyrene with TBEST or via polymerization of TBEST, followed by partial deprotection to afford a copolymer with repeating units having about 20-30% protecting groups. Partial protection of copolymer... 

Modification of the Amine Modified Poiy(hydroxystyrene-co-methyi methacryiate) (I) with Various Hydroxy Aromatic Esters... 

Poly(2-hydroxy-5-methylquinone) Poly(hydroxystyrene-co-methyl methacrylate)... 

Cross-Linker. It is well known that polyfunctional benzylic alcohols act as good crosslinkers for poly(4-hydroxystyrene) (11). This acid-catalyzed cross-linking reaction was studied in detail, and the reaction was proposed to proceed via a direct C-alkylation as well as an initial O-alkylation, followed by a subsequent acid-catalyzed rearrangement to the final alkylated product. Furthermore, both a thermal cross-linking and an acid-catalyzed cross-linking process were proposed for this alkylation (72). Thus we decided to use 4,4 -methylenebis[2,6-bis(hydroxymethyl)phenol] (MBHP) and 2,6-bis(hydroxy-methyl)phenol (BHP) in conjunction with 1 and 2, respectively, on the basis of its avail-... 

A PAG-bound EUV resist of the t-BOC type was reported by Y. Fukushima et al. i The EUV resist is shown in Figure 3.14. The main chain of the EUV resist is composed of copoly(BOCST-HST), where BOCST is t-BOC-hydroxy-styrene and FIST is hydroxystyrene. PAG is bound directly with the main chain. The PAG TSDPPS is tritolylsulfonium-m,m -diisopropylstyrene sulfonium. It was confirmed that the LER of the PAG-bonded resist was smaller than that of the PAG-blended resist. Uniformity of PAG in the PAG-bonded base resin had higher uniformity than that in the PAG-blended resist. ... 

The similar treatment in the presence of chlorogenic acid produced the modified chitosan soluble imder both acidic and basic conditions (311). On the other hand, the tyrosinase-catalyzed reaction of 3,4-dihydroxyphenylethylamine (dopamine) provided water-resistant adhesive properties to chitosan (312). A chitosan derivative modified with hydroxy or dihydroxybenzaldehyde was cross-linked by tyrosinase to give stable and self-sustaining gels (313). Phenolic moiety of a synthetic polymer, poly(p-hydroxystyrene), was also subjected to tyrosinase-catalyzed oxidation (314). 

When we use a hydrophilic polymer like poly(4-hydroxystyrene) or poly(2-(2-(4-vinyl phenoxy)-ethoxy)-ethanol), which will show hydroxy groups at die surface after reconstruction, we are able to deposit selectively inoiganic materials like titanium dioxideor copper" on these parts. 

Hydroxycinnamic acids (HCAs), comprising p-coumaric, ferulic, caffeic and sinapic, and their bound forms, are found in citrus fruit parts (d5). During processing and storage of citrus juices, vinyl phenols are produced from the free HCA by acid-catalyzed decarboxylation. The decarboxylation of all HCAs would potentially produce p-vinyl phenol (from p-coumaric acid), p-vinyl guaiacol (ferulic acid), p-vinyl catechol (caffeic acid) and 3,5-dimethyl-4-hydroxystyrene (sinapic acid). P-vinyl phenol and p-vinyl guaiacol have been identified in processed citrus juices, but p-vinyl catechol and 3,5-dimethyl-4-hydroxy styrene have yet to be reported. Vinyl phenols are unpleasant smelling compoimds with very low perception thresholds their presence adversely affects acceptability of citrus juice products. 

Compatible blends of PC with certain vinyl polymers have been described (35). The compatibilizer acts in the presence of a transesterification catalyst under conditions that effect transesterification. The compatibilizer is a copolymer containing hydroxyl groups, e.g., made from a-methyl-p-hydroxystyrene and methyl methacrylate. Other hydroxyl groups containing monomers may be p-hydroxy-styrene and p-isopropenyl-o-cresol. 

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