Hydroxystyrene

PHOST represents poly(4-hydroxystyrene). The properties of the isomeric poly(2-hydroxystyrene) and poly(3-hydroxystyrenes) differ substantially (87). 

The decarboxylation of 4-hydroxycinnamic acid to 4-hydroxystyrene, and of fernlic acid (3-methoxy-4-hydroxycinnamic acid) to 4-vinylgnaiacol by several strains of Haf-nia alvei and H. protea, and by single strains of Enterobacter cloacae and K. aerogenes (Fignre 2.7d) (Findsay and Priest 1975). The decarboxylase has been pnrihed from Bacillus pumilis (Degrassi et al. 1995). 

This procedure has been used in the preparation of other nitrostyrenes in the following yields o-nitrostyrene (40%),2 / -nitrostyrene (41%),2 and 3-nitro-4-hydroxystyrene (60%).2 A better procedure for more volatile styrenes involves simultaneous decarboxylation and codistillation with quinoline from the reaction flask. This method has been used to prepare the following styrenes o-chlorostyrene (50%),3 4 m-chlorostyrene (65%),4 -chlorostyrene (51%),4 m-bromostyrene (47%),4 o-methoxystyrene (40%),4 -methoxystyrene (76%),4 m-cyano-styrene (51%),3 and j -formylstyrene (52%).9... 

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. 

In another application, the diazonium salt (D1 or D2) (2.5 wt%) was dissolved in a mixture of cyclohexanone and acetic acid containing 12.5 wt% poly(4-hydroxystyrene) and 2. 5 wt% Methylone resin (GE 75108). The resist was exposed with a 600-W Xe-Hg lamp through a 313-nm interference filter. After exposure the resist was baked at 80V for 3 minutes and developed in a 1 wt% tetramethylammonium hydroxide aqueous solution. 

Figure 11. Exposure curve of the acid-catalyzed resist system consisting of poly(4-hydroxystyrene), D2, and...

UV spectra of both polymers IV and V taken from ca. ljim thick films showed that the each of the polymers had absorbencies of less than 0.30 per micron of film thickness at 254 nm as shown in Figure 6 for polymer V. This allows their use with triarylsulfonium salts, which generally absorb in the deep UV. In addition, it is known that poly(4-hydroxystyrene) does not absorb strongly in the deep UV, while poly(3,5-dimethyl-4-hydroxystyrene) also shows no strong absorption band near 254 nm (Figure 6). 

While this work has focused on certain allylic and benzylic ether derivatives of poly(4-hydroxystyrene) it is possible to extend the concept to the corresponding t-butoxy substituted polymers although the preparation of such polymers is relatively more difficult than in the present case. 

Figure 4.2 An Archimedean tile morphology for blends of poly(2-vinylpyridine-/)-isoprene-/)-vinylpyridine) with poly(styrene-/)-4-hydroxystyrene) in a 2 1 vinylpyridine/hydroxystyrene blend. The vinylpyridine/hydroxystyrene domains are the cylinders at the vertices of polystyrene hexagons within a polyisoprene continuous phase. Reprinted from Asari et al. (2006). Copyright 2006 American Chemical Society.

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. 

Research Focus Method of preparing 4-hydroxystyrene by de-carboxylation of 4-hydroxylcinnamic acid for use in preparing poly(4-glycidyloxystyrene). Originality While the thermal decarboxylation of cinnamic acid as a method of... 

Poly(4-hydroxystyrene) was previously prepared by the authors (2) by the decarboxylation of 4-hydroxycinnamic acid followed by the free radical polymerization using Vazo 67. 

The bottom antireflective coating solution test consisted of the step 1 product, poly(4-hydroxystyrene-9-anthracenyl-methacrylate) (1.5 g), 55/45 molar ratio, respectively, oxalic acid/triethylamine (0.075 g) 1 1, triphenylsulfonium triflate (0.06 g), and Vectomer 5015 (0.225 g) dissolved in ethyl lactate (98.5 g) and then filtered through... 

Westover et al. 95 prepared lightly crosslinked nitrated poly(4-hydroxystyrene) microspheres for pH sensors. The microspheres were produced using SPG membranes followed by suspension polymerization and they showed diameters between 1 and 2 micrometers. 

Tyrosinase catalyzes the oxidation of phenols. These enzymes are widespread in fungi, plants, and animals. Polyhydroxystyrene (PHS) is a phenol-containing polymer used as the excellent polymer matrix due to its good coating properties. Phenol moieties of PHS can be oxidized by tyrosinase. Mushroom tyrosinase was observed to catalyze the oxidation of 1-2% phenolic moieties of the synthetic polymer poly (4-hydroxystyrene) (PHS) (Shao et al., 1999) (Figure 4.5). 

Fig. 6 TEM image of a 50 50 diblock copolymer blend of poly(isoprene-l)/ocfc-2-vinylpyridine) (IP) and poly(styrene-6ZocA -4-hydroxystyrene) (SH). Reprinted with permission from [44], 2005 American Chemical Society...

Fig. 8 Illustration of a (3.4.6.4) Archimedian tiling self-assembled structure of a 2 1 blend of poly(2-vinylpyridine)-l>Zocfc-polyisoprene-l)Zocfc-poly(2-vinylpyridine) and polystyrene-fcZocfc-poly(4-hydroxystyrene). P denotes poly(2-vinylpyridine), H denotes poly(4-hydroxystyrene), S denotes polystyrene and I denotes polyisoprene. Reprinted with permission from [45]. 2006 American Chemical Society...

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