4,4 -Dihydroxydiphenyl

Thermotropic polycarbonates have been prepared from mixtures of 4,4 -dihydroxybiphenyl and various diphenols (10). Nematic melts were found for copolycarbonates prepared from methyfliydroquiaone, chlorohydroquiaone, 4,4 -dihydroxydiphenyl ether, and 4,4 -dihydroxybenzophenone. Slightly crystalline polycarbonates have been prepared from mixtures of hydroquinone and BPA (T = 154°C, =313°C, AH = 11.0 J/g (2.63 cal/g)), and... 

Preparation of Disodium 4,4 -Disu/foxy-Dipheny/-(2-Pyridyl)-Methane In % hour, 102 g chlorosulfonic acid are added to a solution of 100 g 4,4 -dihydroxydiphenyl-(2-pyridyl)-methane in 750 ml of anhydrous pyridine, the temperature being maintained at between 0° and 5°C. Towards the end of the addition of acid, a precipitate is formed which is slowly redissolved during subsequent agitation. 

Upon completion of the addition, the mixture is agitated for 7 hours at ambient temperature. The solution is then poured into 3 liters of water/ice obtaining a clear solution of dark yellow color which is rendered alkaline upon phenolphthalein with 30% NaOH and extracted with ethyl ether to eliminate the majority of the pyridine. The mixture is filtered with active charcoal, the pH adjusted to 8 with hydrochloric acid 1 1 and extracted with chloroform to remove the 4,4 -dihydroxydiphenyl-(2-pyridyl)-methane which has not reacted. 

The use of the enolsilyl ether of 1-menthone [16, 19, 21-23] and of some free triflic acid favors the formation of the thermodynamically controlled products as with free 2,2 -dihydroxydiphenyl [22] and only subsequently added HMDS 2 [22]. On reacting silylated alcohols and carbonyl compounds with pure trimethylsilyl triflate 20 under strictly anhydrous conditions no conversion to acetals is observed [24]. Apparently, only addition of minor amounts of humidity to hydrolyze TMSOTf 20 to the much stronger free triflic acid and hexamethyldisiloxane 7 or addition of traces of free triflic acid [18-21, 24, 26] or HCIO4 [25] leads to formation of acetals. 

The oxidation of dihydroxy aromatic compounds under the conditions used by Goldschmidt ususually leads to the formation of quinones rather than diradicals. For example, >,/> -dihydroxydiphenyl gives >-diphenoquinone. Several attempts have been made to oxidize o.o -dihydroxydiphenyl, but without success. The product would be of special interest because of the possible equilibrium among diradical, quinone, and peroxide isomers ... 

N,N-Dimethylacetamide (DMAc), 4-fluorobenzoic acid, 4-fluorobenzoyl chloride, aluminum chloride, 1 -bromonaphthalene, nitrobenzene, ferric chloride, dimethyl sulfone, 4,4 -dihydroxybiphenyl (DHB), and potassium carbonate were obtained from Aldrich and used without purification. 4,4-(Hexafluoroiso-propylidiene)-diphenol (6F-BPA), 9,9-bis(4-hydroxyphenyl)fluorene (HPF), and l,l-bis(4-hydroxyphenyl)-l-phenylethane (Bisphenol AP) were obtained from Ken Seika Corporation and used without purification. 4,4 -Dihydroxydiphenyl sulfone (DHDS) was obtained from Nachem Incorporated and used without purification. 

A solution of 30 parts by weight of pinacolin alcohol in ether is saturated with hydrogen chloride at room temperature and the ether solution then agitated with bicarbonate. After concentration by evaporation it leaves behind the crude diethylstilbestrol [a,p-(p,p -dihydroxydiphenyl)-a,p-diethylethylene] which, when recrystallized from benzene, melts at 170°C to 171°C. The yield amounts to 75% of the calculated. The total yield of diethylstilbestrol, calculated on p-hydroxypropiophenone, is 68% of the theoretical. 

---