Catalysts phosphoric acid

Polygas Olefins. Refinery propylene and butenes are polymerized with a phosphoric acid catalyst at 200°C and 3040—6080 kPa (30—60 atm) to give a mixture of branched olefins up to used primarily in producing plasticizer alcohols (isooctyl, isononyl, and isodecyl alcohol). Since the olefins are branched (75% have two or more CH groups) the alcohols are also branched. Exxon, BASE, Ruhrchemie (now Hoechst), ICl, Nissan, Getty Oil, U.S. Steel Chemicals (now Aristech), and others have all used this olefin source. 

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). 

Phosphates are the principal catalysts used in polymerization units the commercially used catalysts are Hquid phosphoric acid, phosphoric acid on kieselguhr, copper pyrophosphate pellets, and phosphoric acid film on quartz. The last is the least active and has the disadvantage that carbonaceous deposits must occasionally be burned off the support. Compared to other processes, the one using Hquid phosphoric acid catalyst is far more responsive to attempts to raise production by increasing temperature. 

Currently, almost all cumene is produced commercially by two processes ( /) a fixed-bed, kieselguhr-supported phosphoric acid catalyst system developed by UOP and (2) a homogeneous AlCl and hydrogen chloride catalyst system developed by Monsanto. 

Acid-Gatalyzed Synthesis. The acid-catalysed reaction of alkenes with hydrogen sulfide to prepare thiols can be accompHshed using a strong acid (sulfuric or phosphoric acid) catalyst. Thiols can also be prepared continuously over a variety of soHd acid catalysts, such as seoHtes, sulfonic acid-containing resin catalysts, or aluminas (22). The continuous process is utilised commercially to manufacture the more important thiols (23,24). The acid-catalysed reaction is commonly classed as a Markownikoff addition. Examples of two important industrial processes are 2-methyl-2-propanethiol and 2-propanethiol, given in equations 1 and 2, respectively. 

Cumene as a pure chemical intermediate is produced in modified Friedel-Crafts reaction processes that use acidic catalysts to alkylate benzene with propylene (see Alkylation Friedel-CRAFTSreactions). The majority of cumene is manufactured with a soHd phosphoric acid catalyst (7). The remainder is made with aluminum chloride catalyst (8). 

Hibemia-Chemie has described a vapor-phase process that passes fresh and recycled 85 wt % phosphoric acid over a catalyst of hydrochloric acid-leached bentonite impregnated with phosphoric acid. Catalyst activity was claimed to remain constant over a period of one year at the following conditions (126) ... 

Manufacture. Much of the diethyl ether manufactured is obtained as a by-product when ethanol (qv) is produced by the vapor-phase hydration of ethylene (qv) over a supported phosphoric acid catalyst. Such a process has the flexibiHty to adjust to some extent the relative amounts of ethanol and diethyl ether produced in order to meet existing market demands. Diethyl ether can be prepared directly to greater than 95% yield by the vapor-phase dehydration of ethanol in a fixed-bed reactor using an alumina catalyst (21). 

Further evidence against the formation of a free carbonium ion in the alkylation reaction is obtained from the fact that in the presence of boron trifluoride-phosphoric acid catalyst, but-l-ene, but-2-ene, and i-butene react at different rates with alkylbenzenes, yet they would each give the same carbonium ion. In addition, only the latter alkene gave the usual activation order (in this case the hyper-... 

In 1950 the Fischer-Tropsch synthesis was banned in Germany by the allied forces. Sinarol, a high paraffinic kerosene fraction sold by Shell, was used as a substitute. This ban coincided with the rapid development of the European petrochemical industry, and in due time Fischer-Tropsch synthesis applied to the production of paraffins became uneconomic anyway. After the war there was a steady worldwide increase in the demand for surfactants. In order to continually meet the demand for synthetic detergents, the industry was compelled to find a substitute for /z-paraffin. This was achieved by the oligomerization of the propene part of raffinate gases with phosphoric acid catalyst at 200°C and about 20 bars pressure to produce tetrapropene. Tetrapropene was inexpensive, comprising a defined C cut and an olefinic double bond. Instead of the Lewis acid, aluminum chloride, hydrofluoric acid could now be used as a considerably milder, more economical, and easier-to-handle alkylation catalyst [4],... 

Tetrapropylene is manufactured from propylene (containing 50% propane) with the use of a phosphoric acid catalyst at 70-bar pressure and 200°C. Under these conditions a product mixture is obtained which has to be purified by distillation. Unconverted propane is obtained as the first fraction, followed by tripropylene which can either be sent back to the polymerization or used as motor fuel. The third fraction consists of the desired tetrapropylene. 

Under microwave irradiation and applying MCM-41-immobilized nano-iron oxide higher activity is observed [148]. In this case also, primary aliphatic alcohols could be oxidized. The TON for the selective oxidation of 1-octanol to 1-octanal reached to 46 with 99% selectivity. Hou and coworkers reported in 2006 an iron coordination polymer [Fe(fcz)2Cl2]-2CH30H with fez = l-(2,4-difluorophenyl)-l,l-bis[(l//-l,2,4-triazol-l-yl)methyl]ethanol which catalyzed the oxidation of benzyl alcohol to benzaldehyde with hydrogen peroxide as oxidant in 87% yield and up to 100% selectivity [149]. An alternative approach is based on the use of heteropoly acids, whereby the incorporation of vanadium and iron into a molybdo-phosphoric acid catalyst led to high yields for the oxidation of various alcohols (up to 94%) with molecular oxygen [150]. 

The transportation fuels produced and marketed (Table 18.9)40 met the South African fuel specifications of that time and included some coal-derived liquids (not shown in Figure 18.5). Although the refinery originally produced no jet fuel, it was demonstrated that the hydrogenated kerosene range oligomers from olefin oligomerization over a solid phosphoric acid catalyst met the requirements for jet fuel.38 (Semisynthetic jet fuel was approved in 1999 and fully synthetic jet fuel was approved in 2008 DEFSTAN 91-91/Issue 6). 

Much ethanol is manufactured by the hydration of ethene. The reaction is an addition reaction between steam and ethene at 300 °C, in the presence of a solid phosphoric acid catalyst, at a pressure of about 70 atmospheres. 

In 2007, AntiUa and coworkers described the Brpnsted add-catalyzed desymmetrization of me yo-aziridines giving vicinal diamines [75]. hi recent years, chiral phosphoric acids have been widely recognized as powerful catalysts for the activation of imines. However, prior to this work, electrophiles other than imines or related substrates like enecarbamates or enamides have been omitted. In the presence of VAPOL-derived phosphoric acid catalyst (5)-16 (10 mol%) and azidotrimethylsilane as the nucleophile, aziridines 129 were converted into the corresponding ring-opened prodncts 130 in good yields and enantioselectivities (49-97%, 70-95% ee) (Scheme 53). 

In this paper we report the use of supported heteropoly acid (silicotungstic acid) and supported phosphoric acid catalysts for the acylation of industrially relevant aromatic feedstocks with acid anhydrides in the synthesis of aromatic ketones. In particular, we describe the acylation of thioanisole 1 with iso-butyric anhydride 2 to form 4-methyl thiobutyrophenone 3. The acylation of thioanisole with acetic anhydride has been reported in which a series of zeolites were used as catalysts. Zeolite H-beta was reported to have the highest activity of the zeolites studied (41 mol % conversion, 150°C) (2). 

Skeletal isomerization requires higher temperature and stronger acid catalysts than do double-bond migration and cis-trans isomerization. Butylenes, for example, are transformed to isobutylene over supported phosphoric acid catalysts.98 The equilibrium mixture at 300°C contains approximately equal amounts of straight-chain and branched butenes. Similar studies were carried out with pentene isomers.99 Side reactions, however, may become dominant under more severe conditions.100... 

Reaction XL. (6) Action of Carbon Monoxide on Alcohols under pressure in Presence of Catalysis. (J. C. S., 1936, 358.)—Acetic acid and higher acids can be formed by the action of carbon monoxide on the alcohol at 330° and 200 atm. in presence of phosphoric acid catalysts. Branched chain acids may be formed from normal alcohols, through the intermediary of the olefines derived from the alcohols by dehydration. 

Cumene is produced by an alkylation reaction, and most cumene has been produced over solid phosphoric acid catalyst, although some quantities have been produced by liquid phosphoric acid and aluminum chloride. Cumene is used as a raw material for the production of phenol and acetone by oxidation. 

Figure 3 shows a flow diagram of a unit for the production of ethylbenzene using aluminum chloride catalyst, and Fig. 4 shows a flow diagram of a similar unit employing solid phosphoric acid catalyst. 

Fig. 4. Typical ethylbenzene unit with solid phosphoric acid catalyst.

The most important chamber type alkylation units are the UOP type using solid phosphoric acid catalyst for making cumene and ethylbenzene... 

Phosphoric acid polymerization a process using a phosphoric acid catalyst to convert propene, butene, or both, to gasoline or petrochemical polymers. 

A hindered BINAP-phosphoric acid catalyst allows the enantioselective reduction of ketimines via transfer hydrogenation.307 Imines can be generated in situ from either aliphatic or aromatic ketones, with low catalyst loading. 

Phosphoric acid catalysts, bearing bulky groups, have been devised for the asymmetric transfer hydrogenation of imines with Hantsch ester. With the catalyst (14), (g) enantioselectivity up to 93% has been achieved in the reduction of aromatic imines. 

Reaction time is interrelated with catalyst activity and, within limits, to operating pressure. The Solid Phosphoric Acid catalyst is the most ac-... 

The Solid Phosphoric Acid catalyst is produced from a controlled mixture of liquid phosphoric acid and kieselguhr. The catalyst is white or gray cylindrical-shaped pellets. It is hard when dry but picks up water on exposure to moist air for extended periods of time. 

Early commercial units utilized 10- to 20-mesh quartz but, because of the low surface area and consequent low activity of the catalyst, the quartz size was reduced to 28 to 35 mesh. The quartz is activated by pumping the reactor full of 75% phosphoric acid, allowing the excess acid to drain out, and then charging hot hydrocarbon to the unit. Even with the smaller quartz particles the catalyst activity is much lower than that of the Solid Phosphoric Acid catalyst. This lower activity has resulted in lower olefin conversion in this type of unit. Increased conversion has been obtained by separating the olefins from the product with very efficient fractionators and returning them to the reactor. However, this factor requires relatively large units with high utility consumption. 

The Liquid Phosphoric Acid catalyst is very corrosive at elevated temperatures and therefore all hot lines are alloy and all hot vessels are alloy clad, including the catalyst chamber and all catalyst-chamber internals. Stainless steel is used for this corrosion protection and in some severe cases nickel has been used for some internal parts. 

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