Saturation, aromatic rings

A bioprocess for the production of fuels (and fertilizers) from coal using a consortium of bacteria designated KSARC56 or Mic-1 has been disclosed by Walia and 

Srivastava [434,435], The process can be carried out under aerobic (KSARC56) or anaerobic conditions (Mic-1). The identified products include methane, lower alcohols, volatile fatty acids, and/or humic acid. For aromatic feeds the main products are phenols (and derivatives), methane and carbon dioxide. The process is carried out in a slurry phase, at pH of 7.8, under moderate stirring using a bacteria concentration less than 20%. The feed concentration could not exceed more than 50%, as stated in the patent document. In the aerobic operation, the thermophilic consortium KSARC56 is operated for 48 hours at a temperature of up to about 60°C. For the anaerobic operation a mixture of N2 C02 of about 80 20 was used. 

A process, which considered the bio-oxidation of naphthalene compounds using naphthalenes-oxidizing bacteria, was applied for the treatment of gas oil. The quality of the product not only exhibited a sulfur content closed to specifications but also a high lubricity. Description on the used microbial strain was not provided [432], 

Another process for converting organic ring compounds was disclosed for producing value-adding products from fossil fuel, under anaerobic conditions [442], The process is employed at subsurface level, at a depth of at least 500 ft below ground surface. The 

A method to produce synthetic oil by contacting the crude oil with Vibrio furnissii Ml (PERM P-18382) was disclosed by Miyamoto et al. [443], 

---

Ruthenium is excellent for hydrogenation of aliphatic carbonyl compounds (92), and it, as well as nickel, is used industrially for conversion of glucose to sorbitol (14,15,29,75,100). Nickel usually requires vigorous conditions unless large amounts of catalyst are used (11,20,27,37,60), or the catalyst is very active, such as W-6 Raney nickel (6). Copper chromite is always used at elevated temperatures and pressures and may be useful if aromatic-ring saturation is to be avoided. Rhodium has given excellent results under mild conditions when other catalysts have failed (4,5,66). It is useful in reduction of aliphatic carbonyls in molecules susceptible to hydrogenolysis. 

Hydrogen sulfide At low levels, hydrogen sulfide can inhibit aromatic ring saturation. This results in higher-octane gasoline and low-smoke-point jet fuel. At high concentrations, cracking catalyst activity is adversely affected. 

Unsaturated carbon structures usually undergo addition of fluorine, but are vulnerable to fragmentation unless fluorine addition is carefully controlled. Aromatic rings saturate, but polymerization may be a serious side reaction. Many heteroaromatic molecules polymerize giving principally tars and oils. In contrast to the cobalt(III) fluoride process, benzene produces a significantly lower yield of perfluorocyclohexanc than does cyclohexane. 

There are variations in representation of rings in different disciplines. The dye industry does not designate aromaticity or double bonds in rings. AH double bonds and aromaticity are shown in the Encyclopedia as a matter of course. For example, tetralin has an aromatic ring and a saturated ring and its stmcture appears in the Encyclopedia with its common name. Registry Number enclosed in brackets, and parenthetical CA index name, ie, tetralin [119-64-2] (1,2,3,4-tetrahydronaphthalene). With names and stmctural formulas, and especiaHy with CAS Registry Numbers, the aim is to help the reader have a concise means of substance identification. 

Antimoay peatafluoride is used to saturate double boads ia straight-chain olefias, cycloolefias, aromatic rings (19—21), and ia the fluoriaatioa of halocarboas and CrO CL, MoCL, WCL, PCL, P.O.., SiCL, TiCL, and SiO. ... 

Aromatic rings in lignin may be converted to cyclohexanol derivatives by catalytic hydrogenation at high temperatures (250°C) and pressures (20—35 MPa (200—350 atm)) using copper—chromium oxide as the catalyst (11). Similar reduction of aromatic to saturated rings has been achieved using sodium in hquid ammonia as reductants (12). 

Hydrogenation Reactions. Hydrogen over a nickel, platinum, or paladium catalyst can partially or totally saturate the aromatic ring. Thermal hyrogenolysis of toluene yields benzene, methane, and biphenyl. 

Aromatic rings are hydrogenated with a variety of catalysts. However, aromatic alkoxy and hydroxyl substituents are susceptible to hydrogenolysis under most conditions used to saturate the ring. Hydrogenolysis does not occur to any appreciable extent with ruthenium catalysts even though high temperatures and pressures are required. Thus, substituted phenols are... 

CaveU and Chapman made the interesting observation that a difference exists between the orbital involved in the quatemization of aromatic nitrogen heterocycles and aromatic amines, which appears not to have been considered by later workers. The lone pair which exists in an sp orbital of the aniline nitrogen must conjugate, as shown by so many properties, with the aromatic ring and on protonation or quatemization sp hybridization occurs with a presumed loss of mesomerism, whereas in pyridine the nitrogen atom remains sp hybridized in the base whether it is protonated or quaternized. Similarly, in a saturated compound, the nitrogen atom is sp hybridized in the base and salt forms. 

Saturation of the aromatic ring of pentopril analogues is also consistent with ACE inhibition as demonstrated by the oral activity of indolapril (23). The necessary heterocyclic component (21) can in principle be prepared by catalytic perhydrogenation (Rh/C, HOAc) of the corresponding indole. A single isomer predominates. The product is condensed by amide bond formation with the appropriate alanylhomophenylalanyl dipeptide ester 20 to give 22. Selective saponification to 23 could be accomplished by treatment with HCl gas. Use of the appropriate stereoisomers (prepared by resolution processes) produces chiral indolapril [8]. 

Rhenium oxides are also useful in reduction of carboxylic acids (170" C, 3500 psig). Aromatic acids can be reduced to alcohols without ring saturation 3,4,S,6). Strongly synergistic effects were found on substituting half of the Re207 with rulhenium-on-carbon, and excellent results can be obtained al... 

Reduction of anilines containing acid, ester, or carbonyl functions provides a convenient entry to bi- and tricyclic systems, cyclization occurring once the rigidity of the aromatic ring has been lost through saturation (1,2,61,77). 

Aldehydes Saturated aldehydes absorb at 1730 cm-1 aldehydes next to either a double bond or an aromatic ring absorb at 1705 cm-1. 

---