Phillips Reactions

Benzimidazoles containing nitro group in the arylene fragment are obtained in the reaction of carboxylic acids or their derivatives with nitro-substituted 1,2-diamino-benzenes. This method is especially often used for the synthesis of 4-nitro- and 7-nitrobenzimidazoles, since the latter cannot be obtained by direct nitration of benzimidazoles. In most cases the reaction is carried out in the presence of HC1 (the Phillips reaction) [46, 47, 52, 53, 75, 79, 100, 329-340], Nitrobenzimidazoles... 

Figure 8.10. Stripping reaction with deuterons (Oppcnhciiner- Phillips reaction).

FIGURE 18 Preparation of substituted 2,6-bis(benzimidazol-2-yl)pyridine ligands L17 following (A) original intermolecular Phillips reaction, (B) intramolecular Piguet cycliza-tion, and (C) Krdhnke methodology. 

Cambell [78] has described an isotope dilution method for the determination of vinyl acetate in vinyl acetate-vinyl chloride copolymers. In this method a known amount of acetic 2- C acid is added to a solution or suspension of the resin in methyl ethyl ketone and the ester is hydrolysed with sodium hydroxide. The major portion of the sodium acetate is isolated and converted to 2-methyl benzimidazole-methyl C by means of the Phillips reaction [79] with o-phenylene diamine. 

Formation of acetaldehyde and metallic Pd by passing ethylene into an aqueous solution of PdCl2 was reported by Phillips in 1894 15] and used for the quantitative analysis of Pd(II)[16], The reaction was highlighted after the industrial process for acetaldehyde production from ethylene based on this reaetion had been developed[l,17,18]. The Wacker process (or reaction) involves the three unit reactions shown. The unique feature in the Wacker process is the invention of the in situ redox system of PdCl2-CuCl2. 

Oxidation of Ethylene. In 1894 F. C. Phillips observed the reaction of ethylene [74-85-17 in an aqueous paHadium(II) chloride solution to form acetaldehyde. 

Ryton fibers are high performance products developed by Phillips Petroleum Co. by reaction of -dichloroben2ene with sodium sulfide in the presence of a polar solvent according to the following ... 

Molecular Weight. PE mol wt (melt index) is usually controlled by reaction temperature or chain-transfer agents. Reaction temperature is the principal control method in polymerization processes with Phillips catalysts. On the other hand, special chemical agents for chain transfer are requited for... 

Molecular Weight Distribution. In industry, the MWD of PE resins is often represented by the value of the melt flow ratio (MER) as defined in Table 2. The MER value of PE is primarilly a function of catalyst type. Phillips catalysts produce PE resins with a broad MWD and their MER usually exceeds 100 Ziegler catalysts provide resins with a MWD of a medium width (MFR = 25-50) and metallocene catalysts produce PE resins with a narrow MWD (MFR = 15-25). IfPE resins with especially broad molecular weight distributions are needed, they can be produced either by using special mixed catalysts or in a series of coimected polymerization reactors operating under different reaction conditions. 

Most chromium-based catalysts are activated in the beginning of a polymerization reaction through exposure to ethylene at high temperature. The activation step can be accelerated with carbon monoxide. Phillips catalysts operate at 85—110°C (38,40), and exhibit very high activity, from 3 to 10 kg HDPE per g of catalyst (300—1000 kg HDPE/g Cr). Molecular weights and MWDs of the resins are controlled primarily by two factors, the reaction temperature and the composition and preparation procedure of the catalyst (38,39). Phillips catalysts produce HDPE with a MJM ratio of about 6—12 and MFR values of 90—120. 

Chromium Oxide-Based Catalysts. Chromium oxide-based catalysts were originally developed by Phillips Petroleum Company for the manufacture of HDPE resins subsequendy, they have been modified for ethylene—a-olefin copolymerisation reactions (10). These catalysts use a mixed sihca—titania support containing from 2 to 20 wt % of Ti. After the deposition of chromium species onto the support, the catalyst is first oxidised by an oxygen—air mixture and then reduced at increased temperatures with carbon monoxide. The catalyst systems used for ethylene copolymerisation consist of sohd catalysts and co-catalysts, ie, triaLkylboron or trialkyl aluminum compounds. Ethylene—a-olefin copolymers produced with these catalysts have very broad molecular weight distributions, characterised by M.Jin the 12—35 and MER in the 80—200 range. 

The first commercial PPS process by Phillips synthesized a low molecular weight linear PPS that had modest mechanical properties. It was usehil in coatings and as a feedstock for a variety of cured injection-molding resins. The Phillips process for preparing low molecular weight linear PPS consists of a series of nucleophilic displacement reactions that have differing reactivities (26). 

Production. Sulfolane is produced domestically by the Phillips Chemical Company (Borger, Texas). Industrially, sulfolane is synthesized by hydrogenating 3-sulfolene [77-79-2] (2,5-dihydrothiophene-l,1-dioxide) (2), the reaction product of butadiene and sulfur dioxide ... 

The primary use of TiCl is as a catalyst for the polymerisa tion of hydrocarbons (125—129). In particular, the Ziegler-Natta catalysts used to produce stereoregular polymers of several olefins and dienes, eg, polypropylene, are based on a-TiCl and A1(C2H3)3. The mechanism of this reaction has been described (130). SuppHers of titanium trichloride iaclude Akso America and Phillips Petroleum ia the United States, and Mitsubishi ia Japan. 

Disproportionation of Olefins. Disproportionation or the metathesis reaction offers an opportunity to convert surplus olefins to other desirable olefins. Phillips Petroleum and Institut Fransais du Petrc le have pioneered this technology for the dimerization of light olefins. The original metathesis reaction of Phillips Petroleum was intended to convert propylene to 2-butene and ethylene (58). The reverse reaction that converts 2-butene in the presence of excess ethylene to propylene has also been demonstrated (59). A commercial unit with a capacity of about 136,000 t/yr of propylene from ethylene via 2-butene has been in operation in the Gulf Coast since 1985 (60,61). In this process, ethylene is first dimerized to 2-butene foUowed by metathesis to yield propylene. Since this is a two-stage process, 2-butene can be produced from the first stage, if needed. In the dimerization step, about 95% purity of 2-butene is achieved at 90% ethylene conversion. 

The Phillips Steam Active Reforming (STAR) process catalyticaHy converts isobutane to isobutylene. The reaction is carried out with steam in tubes that are packed with catalyst and located in a furnace. The catalyst is a soHd, particulate noble metal. The presence of steam diluent reduces the partial pressure of the hydrocarbons and hydrogen present, thus shifting the equHibrium conditions for this system toward greater conversions. 

The first reactor in series in the Arco, lEP, and Phillips processes is adiabatic (vessel filled with catalyst). The exothermic heat of reaction is removed in a pump-around loop where a portion of the reactor contents are taken from the reactor, pumped through an external exchanger, cooled, and returned to the reactor. 

Additive inhibitors have been developed to reduce the contaminant coke produced through nickel-cataly2ed reactions. These inhibitors are injected into the feed stream going to the catalytic cracker. The additive forms a nickel complex that deposits the nickel on the catalyst in a less catalyticaHy active state. The first such additive was an antimony compound developed and first used in 1976 by Phillips Petroleum. The use of the antimony additive reportedly reduced coke yields by 15% in a commercial trial (17). 

Thermodynamics Hendrick C. Van Ness, Michael M. Abbott Heat and Mass Transfer James G. Knudsen, Hoyt C. Hottel, Adel F. Sarofim, Phillip C. Wankat, Kent S. Knaebel Fluid and Particle Dynamics Janies N. Tilton Reaction Kinetics Stanley M. Walas... 

This process has many similarities to the Phillips process and is based on the use of a supported transition metal oxide in combination with a promoter. Reaction temperatures are of the order of 230-270°C and pressures are 40-80 atm. Molybdenum oxide is a catalyst that figures in the literature and promoters include sodium and calcium as either metals or as hydrides. The reaction is carried out in a hydrocarbon solvent. 

The Phillips approach involved the reaction of aryl halides with aromatic nuclei in the presence of Friedel-Crafts catalysts. Whilst many variations in the process existed three main cases were distinguishable. 

Table 8-5 indicates the wide variety of catalysts that can effect this type of disproportionation reaction, and Figure 8-7 is a flow diagram for the Phillips Co. triolefm process for the metathesis of propylene to produce 2-butene and ethylene. Anderson and Brown have discussed in depth this type of reaction and its general utilization. The utility with respect to propylene is to convert excess propylene to olefins of greater economic value. More discussion regarding olefin metathesis is noted in Chapter 9. 

Olefin metathesis is the transition-metal-catalyzed inter- or intramolecular exchange of alkylidene units of alkenes. The metathesis of propene is the most simple example in the presence of a suitable catalyst, an equilibrium mixture of ethene, 2-butene, and unreacted propene is obtained (Eq. 1). This example illustrates one of the most important features of olefin metathesis its reversibility. The metathesis of propene was the first technical process exploiting the olefin metathesis reaction. It is known as the Phillips triolefin process and was run from 1966 till 1972 for the production of 2-butene (feedstock propene) and from 1985 for the production of propene (feedstock ethene and 2-butene, which is nowadays obtained by dimerization of ethene). Typical catalysts are oxides of tungsten, molybdenum or rhenium supported on silica or alumina [ 1 ]. 

As stated above, olefin metathesis is in principle reversible, because all steps of the catalytic cycle are reversible. In preparatively useful transformations, the equilibrium is shifted to one side. This is most commonly achieved by removal of a volatile alkene, mostly ethene, from the reaction mixture. An obvious and well-established way to classify olefin metathesis reactions is depicted in Scheme 2. Depending on the structure of the olefin, metathesis may occur either inter- or intramolecularly. Intermolecular metathesis of two alkenes is called cross metathesis (CM) (if the two alkenes are identical, as in the case of the Phillips triolefin process, the term self metathesis is sometimes used). The intermolecular metathesis of an a,co-diene leads to polymeric structures and ethene this mode of metathesis is called acyclic diene metathesis (ADMET). Intramolecular metathesis of these substrates gives cycloalkenes and ethene (ring-closing metathesis, RCM) the reverse reaction is the cleavage of a cyclo-... 

Phenyl-ethynyl-terminated resins, 267 Phenyltrimethylammonium chloride (PTMAC), 549 Phillips-type catalysts, 431 PhNCO-2-ethyl hexanol reaction, 229 Phosgenation, 222... 

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