2-Chlorostyrene

Organic synthesis preparation of specialty polymers 

Toxicology. By analogy to styrene, 0-chlorostyrene is expected to cause central nervous system depression at extremely high concentrations and possibly irritation of the eyes, nose, and mucous membranes. 

In an inhalation study, groups of rats, rabbits, guinea pigs, and one dog were exposed to 101 ppm o-chlorostyrene 7 hours/day, 5 days/week for 6 months. There were no significant adverse effects on any species, although microscopic examination of the liver and kidneys in all species showed slight changes. 

The 2003 threshold limit value-time-weighted average (TLV-TWA) is 50 ppm (283mg/m ) with a short-term excursion level of 100 ppm (425mg/m ). 

Torkelson TR Summary report of toxicity data to TLV Committee. The Dow Chemical Company, Biochemical Research Laboratories, Midland, MI, February 15, 1967 

This procedure is adapted from the preparation described by Marvel and Schertz. w-Chlorophenylmethylcarbinol also has been prepared from w-chlorobenzaldehyde and methylmagnesium iodide.  

Submitted by C. G. Overberger and J. H. Saunders. Checked by Arthur C. Cope and Theodore T. Foster. 

A 500-ml. three-necked round-bottomed flask is attached to a 250-ml. dropping funnel and a total-condensation variable takeoff fractionating column with a 20 by 1.2 cm. section packed with glass helices (Note 1). The fractionating column is fitted to a 500-ml. receiving flask. In the reaction flask are placed 12.5 g. of powdered fused potassium acid sulfate and 0.05 g. of -butyl-catechol. The flask is immersed in an oil bath maintained at 220-230°, and 145 g. (0.925 mole) of w-chlorophenylmethylcar-binol (p. 28) and 0.05 g. of -/erk-butylcatechol (Note 2) are placed in the dropping funnel. The system is evacuated to a 

The distillate is rinsed into a separatory funnel with 25 ml. of ether, and the organic layer is separated and dried over 10 g. of anhydrous magnesium sulfate. The drying agent is separated and rinsed with 25 ml. of ether, and 0.1 g. of -fey/.-butylcatechol is added to the solution. The ether is removed, and the product is distilled under reduced pressure. w-Chlorostyrene is obtained in a yield of 102-106 g. (80-82.5%), boiling at 55-57°/3 mm.  

5625 (Notes 3 and 4). A small amount (3-8 g.) of w-chloro-phenylmethylcarbinol can be recovered as a higher-boiling fraction. 

---

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... 

The PHIP-NMR spectra shown in Figure 12.27 were obtained during the hydrogenation of 4-chlorostyrene with p-H2 parahydrogen [38]. In order to elimi-... 

Liutkis, J. Parasczak, J. Shaw, J. Hatzaski, M. "Poly-4-Chlorostyrene, A New High Contrast Negative E-Beam Resist," SPE Regional Technical Conference, Ellenville, New York, Nov. 1982, p 223. 

Radical Copolymerization of Styrene with 4-Chlorostyrene (Determination of the Reactivity Ratios)... 

The reactions of styrene, 4-chlorostyrene, 4-methoxystyrene, and methyl acrylate with l,2-bis(dimethylsilyl)benzene (14) catalyzed by Pt(CH2=CH2)(PPh3)2 give the corresponding dehydrogenative double silylation products 15 in good to high yields (equation 7)14. When dimethyl maleate is employed, benzo-l,4-disilacyclohexene 16 (R1 = R2 = C02Me) is obtained as the major product (15/16 = 22/78) (equation 7). In the reactions of 1-alkenes, i.e., ethylene and 1-octene, the formation of monosilylated products is also observed (13-57% yield). On the basis of the fact that no deuterium is incorporated into the products when l,2-dideuterio-l,2-bis(dimethylsilyl)benzene is used, disilyl-Pt metallacycle 17 is proposed to be the key intermediate of this process (equation 7). 

Again FeCl3-6H20 is the catalyst of choice for the benzylation of o-xylene by 4-chlorostyrene (Table 6.2). This iron-catalyzed arylation reaction of styrenes allows the synthesis of a wide variety of 1,1-diarylalkanes employing various styrenes and diverse arenes. Scheme 6.15 illustrates selected examples of successfully synthesized 1,1-diarylalkanes and Table 6.3 shows the diversity of different substituted styrenes employed as benzylating agents. 

Table 6.2 Catalyst screening for the reaction of o-xylene with 4-chlorostyrene .

Reaction conditions 0.5 mmol 4-chlorostyrene, 5mL o-xylene, 20 h. bGC conversion of 4-chlorostyrene. 

Scheme 6.15 Reaction of styrene and 4-chlorostyrene with various (hetero)arenes GC conversion of styrene/GC product yield (regioselectivity). Reaction conditions 0.5 mmol styrene/ 4-chlorostyrene, 10mol% FeCl3, 5mLarene, 80°C, 4h (a)...

Kinetic studies, with both Cu(II) and Ru(II) catalysts, have revealed that this addition is also sensitive to polar effects of substituents on the benzene ring. Thus the order of reactivity, which is 4-methylstyrene> styrene> 4-chlorostyrene> 4-fluorostyrene> 3-nitrostyrene, also supports a coordination mechanism670. 

---