Impurities phenol hydrogenation

Since the coal is heated gradually as it passes slowly down through the bed, the Lurgi reactor produces light oils, tars, and phenols, as well as the usual Impurities of hydrogen sulfide and ammonia. A typical Lurgi gas from bituminous coal has the following dry composition ... 

The neutralized cleavage product, consisting of acetone, phenol, water, hydrocarbons, and trace organic impurities, is separated in a series of distillation columns. Also in this section alpha-methylstyrene is either recovered as a product or hydrogenated to cumene. 

The gas plant products, namely fuel gas, Cfs, 4, and gasoline, contain sulfur compounds that require treatment. Impurities in the gas plant products are acidic in nature. Examples include hydrogen sulfide (HjS), carbon dioxide (COj), mercaptan (R-SH), phenol (ArOH), and naphthenic acids (R-COOH). Carbonyl and elemental sulfur may also be present in the above streams. These compounds are acidic. 

The first reactions concerned (Simons and Archer, 27) alkylation of benzene with propylene to form isopropylbenzene, with isobutene to form f-butylbenzene and di-f-butylbenzene, and trimethylethylene to form amylbenzene. Later on (Simons and Archer, 28) studied these and other reactions in more detail and showed that high yields could be obtained and that the product was not contaminated with tars or other obnoxious impurities. It was shown that the products obtained with trimethylethylene were mono- and di-f-amylbenzene, that phenyl-pentane resulted from the use of pentene-2, and that cyclohexene produced cyclohexylbenzene. Cinnamic acid reacted with benzene (Simons and Archer, 29) to form /3-phenylpropionic acid and allyl benzene reacted with benzene to form 1,2-diphenylpropane. It is interesting to note that although allyl alcohol reacted with benzene to form 1,2-diphenylpropane, the intermediate in the reaction, allylbenzene, was isolated and identified. This shows that in this case the hydroxyl reacted at a more rapid rate than the double bond. Both di- and triisobutylene reacted with phenol (Simons and Archer, 30) at 0°, when using hydrogen fluoride containing only relatively small quantities of water, to form f-butyl-benzene, but diisobutylene with 70% hydrogen fluoride produced p-f-octylphenol. Cyclohexene reacted with toluene to form cyclohexyl-toluene and octene-1 rapidly reacted with toluene to form 2-octyltoluene (Simons and Basler, 31). 

Synonym Liquid Hydrogen Liquid Impure Camphor Liquid Nitrogen Liquid Nitrogen Dioxide Liquid Oxygen Liquid Petrolatum Liquified Phenol Litharge... 

OC-Santalol. Sandalwood oil is comprised of mainly (90%) a- and p-santalol, which gives the oil the woody, tenacious sandalwood odor. An impure a-santalol [115-71-9] (100) can be isolated by the distillation of the oil. p-Santalol [77-42-9] (101) is also isolated but in much smaller amounts. The price of sandalwood oil, E. Indian, in 1995 was 286/kg, and the oil from Indonesia was 187/kg (69). The high price of these oils has created the need to synthesize new materials with the sandalwood odor. The terpenophenols are manufactured by condensation of camphene with phenolic compounds followed by hydrogenation to the cycloaliphatic alcohols (194). 

The impurities can be grouped into two categories lights (water, cyclohexene, cyclohexadiene) and heavies (phenol, dicyclohexyl-ether, cyclohexenyl- cyclohexanone). To limit their amount, the conversion is kept around 80% with a selectivity of about 98%. The hot reactor effluent is cooled in countercurrent with the feed in FEHE, and finally for phase separation in the heat exchanger (E-2) at 33 °C. The simple flash (S-2) can ensure a sharp split between hydrogen, recycled to hydrogenation reactor, and a liquid phase sent to separation. 

Information regarding the physical and chemical properties of benzene is shown in Table 3-2. The major impurities found in commercial products are toluene, xylene, phenol, thiophene, carbon disulfide, acetylnitrile and pyridine (NIOSH 1974). Commercial refined benzene-535 is free of hydrogen sulfide and sulfur dioxide, but contains a maximum of 1 ppm thiophene and a maximum of 0.15% nonaromatics. Refined nitration-grade benzene is free of hydrogen sulfide and sulfur dioxide. Benzene is also commercially available as thiophene-free, 99 mole%, 99.94 mole% and nanograde quality (HSDB 1996). 

The reaction can be carried out more conveniently and in equally good yields by substituting zinc cyanide for the hydrogen cyanide (70-SK)%)/ Potassium chloride impurity in this catalyst is necessary/ Sodium cyanide has also been used/ With these modifications, phenols and ethers as well as hydrocarbons react (cl. method 140). 

A comparison of the rates of reaction of many substituted phenyl esters with N-protected a-amino acids showed that the 2,4,5-trichlorophenyl esters are more reactive than p-nitrophenyl esters and are promising new active derivatives for the synthesis of peptides. One advantage is that the ester group does not interfere with catalytic hydrogenation for removal of the carbobenzoxy group. The esters are prepared by condensation of the N-protected amino aeid and the phenol with dicyclo-hexylcarbodiimide. In the synthesis of a particular hexapeptide, where other methods were unsatisfactory because of poor yields or impure products, Bentley et al. obtained the hexapeptide in 97% yield through the trichlorophenyl ester. J. Pless and R. A. Boissonnas, //elr., 46,1609 (1963)... 

Tall oil fatty acid esters can be easily epoxidized in the presence of hydrogen peroxide and acetic acid. For satisfactory results, the tall oil fatty acid should be pretreated to remove trace phenolic impurities, such as dimethoxystilbene, in order to avoid pink coloration. 

The debenzylation reaction was found to be very sensitive to feedstock impurities. Eigure 8 illustrates the hydrogen uptake of debenzylation reaction of 4-(benzyloxy) phenol from two different feedstock lots. As shown in Figure 8 that the hydrogen uptake was completed in 6000 seconds on a pure feed stock how-... 

Figure 8 Effects of the feedstock impurity on the reaction rate for debenzylation of 4-(benzyloxy) phenol. Reaction conditions methanol solvent, 35°C, 1.1 bar hydrogen, 2000 rpm, 3% catalyst loading (5%Pd/CPS3).

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