Catalyst, alumina boron trifluoride

Alkar [Alkylation of aromatics] Also (incorrectly) spelled Alcar. A catalytic process for making ethylbenzene by reacting ethylene with benzene. The ethylene stream can be of ary concentration down to 3 percent. The catalyst is boron trifluoride on alumina. Introduced by UOP in 1958 but no longer licensed by them. Replaced by the Ethylbenzene process. 

The thiol-epoxy reaction has proved to be an important synthetic tool in the preparation of a variety of pharmaceutical and natural products [55-64]. As mentioned above, this reaction can be performed using an acid or a base as a catalyst. The acid catalysts include boron trifluoride etherate [57], lanthanide chlorides [65], lithium perchlorate [60], cobalt chloride [66], and neutral alumina [67]. The basic catalysts can be organic or inorganic and include, among others, triethylamine, l,8-diazabicyclo[5.4.0]undec-7-ene (DBU), tetra-n-butylammonium fluoride (TBAF), and LiOH [61-64, 68, 69]. In the literature on small molecules, it is important to note that this reaction is complete in a few minutes to a few hours of reaction time, with quantitative yields and with high regioselectivity. In the case of LiOH and TBAF, quantitative conversion of the epoxide to a desired thio-ether compound is observed within minutes and with 100% regioselectivity (isomer I) [68, 69]. 

Toluene reacts with carbon monoxide and butene-1 under pressure in the presence of hydrogen fluoride and boron trifluoride to give 4-methyl-j iYbutyrophenone which is reduced to the carbinol and dehydrated to the olefin. The latter is cycHzed and dehydrogenated over a special alumina-supported catalyst to give pure 2,6- dim ethyl n aph th a1 en e, free from isomers. It is also possible to isomerize various dim ethyl n aph th a1 en es to the... 

Diphenylamine can also be produced by passing the vapors of aniline over a catalyst such as alumina, or alumina impregnated with ammonium fluoride (17). The reaction is carried out at 480°C and about 700 kPa (7 atm). Conversion per pass, expressed as parts diphenylamine per 100 parts of reactor effluent, is low (18—22%), and the unconverted aniline must be recycled. Other catalysts disclosed for the vapor-phase process are alumina modified with boron trifluoride (18), and alumina activated with boric acid or boric anhydride (19). 

The vapor-phase esterification of ethanol has also been studied extensively (363,364), but it is not used commercially. The reaction can be catalyzed by siUca gel (365,366), thoria on siUca or alumina (367), zirconium dioxide (368), and by xerogels and aerogels (369). Above 300°C the dehydration of ethanol becomes appreciable. Ethyl acetate can also be produced from acetaldehyde by the Tischenko reaction (370—372) using an aluminum alkoxide catalyst and, with some difficulty, by the boron trifluoride-catalyzed direct esterification of ethylene with organic acids (373). 

A similar type of catalyst including a supported noble metal for regeneration was described extensively in a series of patents assigned to UOP (209-214). The catalysts were prepared by the sublimation of metal halides, especially aluminum chloride and boron trifluoride, onto an alumina carrier modified with alkali or rare earth-alkali metal ions. The noble metal was preferably deposited in an eggshell concentration profile. An earlier patent assigned to Texaco (215) describes the use of chlorinated alumina in the isobutane alkylation with higher alkenes, especially hexenes. TMPs were supposed to form via self-alkylation. Fluorinated alumina and silica samples were also tested in isobutane alkylation,... 

Licensors offer a variety of catalysts to promote the isomerization— silica alumina by itself or enhanced with a noble metal like platinum or a non-noble metal like chromium. Another uses hydrofluoric acid with boron trifluoride In the case of the noble metal catalytic process, the feed enters a vessel with a fixed catalyst bed at 850°F and 14.5 psi. As is often the case, a small amount of hydrogen is present to reduce the amount of coke laying down on the catalyst. The effluent is processed in a standard fashion to separate the hydrogen, the para- and ortho-xylene, and any unreacted or miscellaneous compounds. Yields of para-xylene are in the 70% range. 

Note that ethylbenzene is a derivative of two basic organic chemicals, ethylene and benzene. A vapor-phase method with boron trifluoride, phosphoric acid, or alumina-silica as catalysts has given away to a liquid-phase reaction with aluminum chloride at 90°C and atmospheric pressure. A new Mobil-Badger zeolite catalyst at 420°C and 175-300 psi in the gas phase may be the method of choice for future plants to avoid corrosion problems. The mechanism of the reaction involves complexation of the... 

Catalyst, alumina, 34, 79 35, 73 ammonium acetate, 31, 25, 27 boron trifluoride etherate, 38, 26 copper chromite, 31,32 36, 12 copper powder in quinoline for pyrolytic decarboxylation,... 

Thenaldehyde (thiophene-2-carbaldehyde) is readily available via the Vilsmeier-Haack reaction of DMF with thiophene catalyzed by phosphorus oxychloride. The Sommelet reaction with 2-chloromethylthiophene also gives reasonable yields (63AHC(l)l). Likewise, thiophene is readily acylated with acyl anhydrides or acid chlorides (equation 14), using mild Friedel-Crafts catalysts, such as tin(IV) chloride, zinc chloride, boron trifluoride, titanium tetrachloride, mercury(II) chloride, iodine and even silica-alumina gels or low-calcium-content montmorillonite clays (52HC(3)l). 

Other Technologies. Ethylbenzene can he recovered from mixed Cs aromatics by superfractionalion. The Alkar process, commercialized in 1960, uses boron trifluoride on alumina support as the catalyst. It has been used for polymer-grade as well as dilute ethylene feeds. 

Indolizines with a saturated six-membered ring may be obtained from pyrrole or furan derivatives.225,226 The reaction of 3,4-dimethylpyrryl-magnesium bromide with y-chlorobutyronitrile followed by dilute acid gave 5,6,7,8-tetrahydro-l,2-dimethyl-5-oxoindolizine. 5,6,7,8-Tetrahy-droindolizine can be obtained by the cyclodehydration of 3-(2-furyl)-propylamine over alumina at 400°C. The same product is obtained by the treatment of 3-(2-pyrryl)propyl cyanide with hydrogen chloride in the presence of boron trifluoride etherate catalyst, followed by Wolff-Kishner reduction of the intermediate ketone. 

The redistribution reaction in lead compounds is straightforward and there are no appreciable side reactions. It is normally carried out commercially in the liquid phase at substantially room temperature. However, a catalyst is required to effect the reaction with lead compounds. A number of catalysts have been patented, but the exact procedure as practiced commercially has never been revealed. Among the effective catalysts are activated alumina and other activated metal oxides, triethyllead chloride, triethyllead iodide, phosphorus trichloride, arsenic trichloride, bismuth trichloride, iron(III)chloride, zirconium(IV)-chloride, tin(IV)chloride, zinc chloride, zinc fluoride, mercury(II)chloride, boron trifluoride, aluminum chloride, aluminum bromide, dimethyl-aluminum chloride, and platinum(IV)chloride 43,70-72,79,80,97,117, 131,31s) A separate catalyst compound is not required for the exchange between R.jPb and R3PbX compounds however, this type of uncatalyzed exchange is rather slow. Again, the products are practically a random mixture. 

Caro s acid, 22, 44, 74 Carvacrylamine, 22, 9 Catalyst, alumina, 22, 40 boron trifluoride, 20, 6 copper bronze, 20, 45 copper-chromium oxide for decarboxylation, 22, 67... 

Other workers also report studies on alkylation of aromatics over silica-alumina (63). Ivanov el al. alkylated coal-tar aromatics with olefins in the presence of aluminum chloride-hydrogen chloride and obtained a product suitable for use as a lubricating oil (143). Topchiev and Paushkin have reported high yields in the alkylation of isopentene with propylene in the presence of a catalyst containing phosphoric acid and boron trifluoride (395). 

UOP introduced the Alkar process for ethylbenzene production in 1966. The Alkar process operates in the vapor-phase with boron trifluoride on an alumina support as the catalyst. By the 1980s, about 15% of the world s ethylbenzene was... 

Supported the catalysts used in this case are silica aluminas, phosphoric add deposited on kieselguiir, or boron trifluoride dqiosited on modified ahimiBa. 

A facile explanation of the failure of acidity to enhance activity of any of the catalysts while base enhances the activity of a poor catalyst without affecting the active ones is that the Claus active catalysts owe their activity to basic sites. In general, alumina shows strong surface acidity when activated at 450 °C in vacuum, and intensive investigation has shown this to happen in Lewis acid sites (8). There is also evidence that basic sites occur on alumina. Schwab and Krai (9) obtained evidence for basic sites by boron trifluoride adsorption on alumina, and Yamadaya et al. (10) reported up to 0.4 mmole/g of basic sites on alumina from benzoic acid titrations. Pines and Manassen (11) obtained indirect evidence of such sites from studies of the dehydration of primary alcohols. 

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