Boron trifluoride, as catalyst

Coumarone—Indene Kesins. These should be called polyindene resins (17) (see Hydrocarbon resins). They are derived from a close-cut fraction of a coke-oven naphtha free of tar acids and bases. This feedstock, distilling between 178 and 190°C and containing a minimum of 30% indene, is warmed to 35°C and polymeri2ed by a dding 0.7—0.8% of the phenol or acetic acid complex of boron trifluoride as catalyst. With the phenol complex, tar acids need not be completely removed and the yield is better. The reaction is exothermic and the temperature is kept below 120°C. When the reaction is complete, the catalyst is decomposed by using a hot concentrated solution of sodium carbonate. Unreacted naphtha is removed, first with Hve steam and then by vacuum distillation to leave an amber-colored resin. It is poured into trays, allowed to cool, and broken up for sale. 

Carbon disulfide gives an essentially quantitative yield of carbon tetrafluoride (4) and sulfur on reaction with sulfur tetrafluoride at 450 C in the presence of arsenic(III) fluoride as catalyst. At lower temperatures and with boron trifluoride as catalyst, bis(trifluoromethyl) polysulfides 5 and 6 are formed.205... 

KUCHEROV REACTION. The hydration of acetylenic hydrocarbons with dilute sulfuric acid in the presence of mercuric sulfate or boron trifluoride as catalyst. 

More recently Italian workers investigated some aspects of cationic anethole polymerizations. Thus Rattu and Secci (140) used aluminum chloride and titanium tetrachloride and Secci and Mameu (141) employed boron trifluoride as catalysts at various temperatures. The latter authors found boron (U. V. spectroscopy) in the polymer and proceeded to propose a rather controversial mechanism. Their hypothesis implies that a cocatalyst is not necessary for the polymerization and the polymerization proceeds as follows ... 

Table 6. Hydrofluorination of Halogenated Alkenes with Boron Trifluoride as Catalyst ...

We used for the further tests the system hydrogen fluoride/ boron trifluoride as catalyst and olefins as means of alkylation. 

More recently, Olah and Kuhn588 have performed such formylations by the relatively stable formyl fluoride at 0-10° in carbon disulfide with boron trifluoride as catalyst yields of 56-78% were obtained from various aromatic hydrocarbons. 

Further examples88 of the facile displacement of a 1-ethoxy group of an isochroman have been given active methylene compounds (72 R=Ac, COOEt) (sometimes with boron trifluoride as catalyst) gave 1-alkyl derivatives (73) mostly, but with malononitrile, the ether (74) was the main product.89... 

In our studies of electrophilic nitrations, we also found alkyl nitrates, particularly methyl nitrate, very effective nitrating agents in the presence of boron trifluoride as catalyst... 

Employing this silylation procedure, thiadiazinones 121 (R=H, Me) reacted with either (propargyloxy)methyl chloride or acetoxymethyl benzyl ether in dichloromethane using boron trifluoride as catalyst to afford mixtures of N -mono- and N N -disubstituted products 122-125 (Scheme 5) <1997NN265>. 

Fluoiination of dichloromaleic anhydride with sulphur tetrafluoride at 300 C in the presence of boron trifluoride as catalyst was used to prepare the perfluoro-... 

As a consequence, a series of other Bronsted and Lewis acids were probed for their impact on the stereoselectivity of cyclisations. Thus, the sclareolide isomers were obtained from homofarnesylic acid in 91 % yield, when the reaction was carried out with stannic chloride in dichloromethane at -78 °C. [249] On the other hand, the use of boron trifluoride as catalyst produced racemic sclareolide in a yield of only 38%. [250] The company Henkel patented a procedure, in which an ( /Z)-mixture of homofarnesylic acid isomers was treated at -10 °C with methanesulfonic acid in dichloromethane, although, this yielded only a mixture of sclareolide isomers. [251]... 

Various l-thio-a-D-aluco-compounds having long chain aglycons were prepared directly from the penta-acetate by use of boron trifluoride as catalyst and were studied as liquid crystals. ... 

Synthesis of polyoxyethylene sterol was first reported by Scotney and Truter [6] in 1971. They simply mixed cholesterol and the appropriate amount of ethylene oxide in a sealed vial during 4 months. Later workers have applied more sophisticated methods to synthesize better defined products. Khachadurian et al. [7] synthesized both polyoxyethylene and methoxypolyoxyethylene derivatives of cholesterol. The former reaction was carried out in dichloromethane using boron trifluoride as catalyst. Derivatives with a methoxy terminal were prepared by condensing methoxypoly(oxyethylene)methanesulfonate with cholesterol in xylene. Commercially available products are produced by the reaction of sterol with ethylene oxide, resulting in a product with a distribution in the number of ethylene oxide (EO) units in the hydrophilic group. Meissner et al. also described the synthesis of sterol sulfate and sulfonate with oxy-ethylene spacers [8], The synthesis of sterol surfactants has been covered in a review by Folmer [9]. There are only a few producers of polyoxyethylene... 

The reaction is performed in hydrofluoric acid at 20°C with boron trifluoride as catalyst. Under these conditions, the polymer remains dissolved and high molecular weights are attained. 

Methods for the synthesis of hop bitter acids are due to the elegant work of RiedI (78-84). The substrates are phloracylphenones, which are readily available from condensation of phoroglucinol with acid chlorides (Friedel-Crafts synthesis), nitriles (Hoesch synthesis) or carboxylic acids with boron trifluoride as catalyst. Carbon acylation of a phloracylphenone can give one monoalkylated derivative (13, Fig. 13), two dialkylated derivatives (14 and 15) and one tri- or tetra-alkylated derivative (16 and 17, respectively). The possibility of oxygen acylation can not be excluded. 

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