Catalytic hydrogenation hydrogen fluoride

The strong catalytic activity of anhydrous hydrogen fluoride results from the abiUty to donate a proton, as in the dimerization of isobutylene (see Butylenes) ... 

Isopropylnaphthalenes can be prepared readily by the catalytic alkylation of naphthalene with propjiene. 2-lsopropylnaphthalene [2027-17-0] is an important intermediate used in the manufacture of 2-naphthol (see Naphthalenederivatives). The alkylation of naphthalene with propjiene, preferably in an inert solvent at 40—100°C with an aluminum chloride, hydrogen fluoride, or boron trifluoride—phosphoric acid catalyst, gives 90—95% wt % 2-isopropylnaphthalene however, a considerable amount of polyalkylate also is produced. Preferably, the propylation of naphthalene is carried out in the vapor phase in a continuous manner, over a phosphoric acid on kieselguhr catalyst under pressure at ca 220—250°C. The alkylate, which is low in di- and polyisopropylnaphthalenes, then is isomerized by recycling over the same catalyst at 240°C or by using aluminum chloride catalyst at 80°C. After distillation, a product containing >90 wt % 2-isopropylnaphthalene is obtained (47). 

Catalysis. Catalytic properties of the activated carbon surface are useful in both inorganic and organic synthesis. For example, the fumigant sulfuryl fluoride is made by reaction of sulfur dioxide with hydrogen fluoride and fluorine over activated carbon (114). Activated carbon also catalyzes the addition of halogens across a carbon—carbon double bond in the production of a variety of organic haUdes (85) and is used in the production of phosgene... 

The vapor-phase catalytic replacement of chlorine by fluorine with hydrogen fluoride as the fluorine source has been the subject of a number of patents for the synthesis of Freons or Genetrons This topic has been carefully reviewed in the literature [2, p 97ff] One advantage of using a catalyst with hydrogen fluoride is to allow some degree of selectivity in the displacement of a specific chlorine from... 

The total yield of products from alkanecarboxyhc acids increases, in most cases, by addition of anhydrous hydrogen fluoride. The optimum hydrogen fluoride concentration is much higher than catalytic and is related to the basicity of a carbonyl group. A mechanism for the formation of both 1,1,1-trifluoroalkanes and bis(l,l-difluoroalkyl) ethers has been proposed [206] (equation 102)... 

Stability toward reduction makes hydrogen fluoride a good medium for different hydrogenation processes [1, 2] It is a useful solvent for the hydrogenation of benzene in the presence of Lewis acids [f ] Anhydrous hydrofluonc acid has pronounced catalytic effect on the hydrogenations of various aromatic compounds, aliphatic ketones, acids, esters, and anhydrides in the presence of platinum dioxide [2] (equations 1-3)... 

Commercially available hydrogen fluoride usually is not suitable for catalytic hydrogenation because of its sulfur dioxide content An oxidative treatment with manganese dioxide and distillation are needed for the preparation of hydrogena tion-grade hydrogen fluoride [d, 4]... 

Fluorodehydroxylation of 5-benzyl-5//-dibenz[f>,/]azepin-10(lli/)-one (47) with hydrogen fluoride and sulfur tetrafluoride followed by catalytic debenzylation of the product 48 provides access to 10-fluoro-5//-dibenz[ft,/]azepine (49).134... 

Reactions that have led to other deoxyhalogeno sugars do not necessarily lead to deoxyfluoro sugars, as, for example, in the attempted decomposition of fluoroformates, the treatment of diazoketones and of 2-deoxy-2-diazohexonates with hydrogen fluoride, and the reaction of benzoxonium ions with halide ions. The reaction2281229 by which fluoroformates are thermally or catalytically decarbonylated to give alkyl fluorides has been applied to carbohydrates. Both thermal and catalytic treatment of 6-0-(fluoroformyl)-l,2 3,4-di-0-isopropylidene-... 

Acetyl-3-methyl-4,5-dihydrothiophen-4-one Benzyl alcohol, Hydrogen bromide, Iron Benzyl bromide, Molecular sieve Benzyl chloride, Catalytic impurities Benzyl fluoride l,2-Bis(chloromethyl)benzene Ethylene oxide, Contaminants Furoyl chloride... 

Probably Frey s most important invention involved the use of hydrogen fluoride to convert light olefins, produced as by-products of a catalytic cracker, into high octane motor and aviation fuels. This process is still widely used. It came at a critical time for America s World War II efforts allowing fuel production for the Allied forces. This fuel allowed aircraft faster liftoffs, more power, and higher efficiency. 

The term hydrogen fluoride is used as the name for the substance containing hydrogen and fluorine, and the formula HF used regardless of the fact that the vapor has been shown to exist as an equilibrium of polymers. By implication the liquid and crystalline material are even more highly polymerized. When emphasis is needed to call attention to the fact that water free material is designated, the term anhydrous hydrogen fluoride is used. The term anhydrous hydrofluoric acid is self-contradictory as hydrofluoric acid is the name for the aqueous solution. In addition, completely anhydrous material is not always necessary or even desirable for catalytic work. The commercial material labeled anhydrous... 

Another essential chemical property catalytically important is the powerful dehydrating action of hydrogen fluoride. No chemical drying... 

As alkylation was the first reaction reported which demonstrated the truly catalytic power of hydrogen fluoride and it is the one now being used on the largest scale in industry, it is appropriate to begin the discussion of specific reactions with alkylation. 

Elsewhere the author has published examples of the use of hydrogen fluoride to catalyze the alkylation of benzene using a variety of alkylating agents (Simons, 22, 23, 24). The breadth and scope of the catalytic power of hydrogen fluoride can be better obtained by a more complete examination of the alkylations now published using this catalyst. For reasons of organization, the subject is divided into aromatic and aliphatic reactions. 

The Jackson laboratory of the du Pont Company soon became interested in the catalytic power of hydrogen fluoride. The results of its work are recorded in three excellent papers. Using acrolein as the alkylating agent and hydrogen fluoride as the catalyst, peri syntheses have been performed (Calcott et al, 32), both those that are catalyzed by sulfuric acid and others that are not. By appropriate condensation, dehydration, and reduction, perylene was obtained from phenanthrene... 

The powerful dehydrating property of hydrogen fluoride would cause it to be expected to assist in reactions in which water is a product. Such dehydration reactions would not in the true sense be catalytic. However, as the addition of water in the case of the hydrolysis of esters (Simons and Meunier, 66) has been shown to be catalyzed by hydrogen fluoride, the catalytic powers of hydrogen fluoride are probably involved in the reverse reaction, as a catalyst must necessarily accelerate the reverse reaction if it does so for the forward one. For this reason some of these reactions are included here. 

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