Aromatics from alcohols

Methanol is the principal feedstock for the production of aromatic gasolines with zeolite catalysts. 

A distinction is made between wide, medium and narrow-pored zeolites. In wide-pored Y-zeolites, the structures leading to the large voids are formed by 12 Si04 or AIO4 tetrahedra. These apertures have a diameter of 7.4 A the largest voids have a diameter of around 13 A. 

In the narrow-pored A-zeolites, 8 tetrahedra produce an aperture of 4.1 A. Between these ranges lie the pentasil zeolites, with a slightly elliptical pore section. These pores are formed from 10 tetrahedra the pore size is approx.5.6 A. 

Zeolites are inorganic ion-exchangers their catalytic activity is basically a result of acid groups on the intracrystalline surface. The zeolites per se can be used as catalysts, but also serve as carriers for active components. The composition of a typical molecular-sieve zeolite is shown in Table 3.29. 

The specific surface of the zeolite catalysts varies between 800 and 1,000 m /g. 

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Aromatic primary alcohols diflfer from aliphatic primary alcohols in that they react with concentrated hydrochloric acid in the cold to yield the corresponding chlorides, for example ... 

Donoi—acceptoi chromogens in solution are often strongly affected by the nature of the solvent or the resinous substrate in which they are dissolved. The more polar the solvent or resin, the longer the wavelength of the fluorescent light emitted. Progressing from less polar to more polar solvents, the bathochromic, or reddening, effect of the solvents on the dye increases in the order of aUphatics < aromatics < esters < alcohols < amides. 

Deposition Precursors. Diamond has been deposited from a large variety of precursors which include, besides methane, aliphatic and aromatic hydrocarbons, alcohols, ketones, and solid polymers such as polyethylene, polypropylene, and polystyrene, and halogens. 

The organic phase indudes aliphatic as well as aromatic adds, alcohols, esters, ethers, sugars and extractives (Table 6.3). Approximately 70 wt.% of the oil has been identified. The molecular weight of the individual components ranges from 18 up to 2000 gram mol-1. In some cases, the oil is an emulsion at microscopic level [58]. 

Polymers and resins Water purification, including removal of phenol, chlorophenols, ketones, alcohols, aromatics, aniline, indene, polynuclear aromatics, nitro- and chlor-aromatics, PCB, pesticides, antibiotics, detergents, emulsifiers, wetting agents, kraftmill effluents, dyestuffs recovery and purification of steroids, amino acids and polypeptides separation of fatty adds from water and toluene separation of aromatics from ahphatics separation of hydroquinone from monomers recovery of proteins and enzymes removal of colours from symps ... 

Hydrocarbons (aromatic) from liquid paraffins NaX, CaX n-Heptane, ethyl alcohol [151]... 

Colorless to white prisms or crystalline plates from alcohol with an odor similar to coal tar or aromatic hydrocarbons. 

In the absence of primary alcohols, secondary alcohols participate in transesterification reactions to provide good yields for most alcohols. No significant electronic effect is observed when electron-releasing and electron-withdrawing substitutents on aromatic secondary alcohols (Table 22, entries 2-4). A steric effect is observed with cyclohexanol derivatives. Increasing the a-substituent from hydrogen to methyl or teri-butyl dramatically decreases efficiency of transesterifi-... 

Then, nucleophilic aromatic substitution was applied for the synthesis of l,2,4,6,7,9-hexafluoro-l,4-dibenzodioxin from 2,3,4,6-tetrafluorophenol in the presence of sodium /-butylate <1995JFC(73)265>. In a similar way, cyano-1,4-dibenzodioxins and cyano-l,4-dibenzodithiins have been synthesized by fluorine displacement reactions with catechols <2001NJC379, 2001NJC385>. In accordance with a similar mechanism, the synthesis of spiro (l,4-benzodioxin-2,4 -piperidines) 205 and spiro (l,4-benzodioxin-2,3 -pyrrolidines) 206 have been developed from alcohols 207 and 208, respectively, both of them being obtained from 2-fluorophenol 210 with the corresponding epoxide 209 (Scheme 18) <2003SL813>. 

An alcohol may be acyclic or cyclic. It may contain a double bond, a halogen atom or additional hydroxyl groups. Alcohols are usually classified as primary (1°), secondary (2°) or tertiary (3°). When a hydroxyl group is linked directly to an aromatic ring, the compound is called a phenol (see Section 4.6.10), which differs distinctly from alcohols. 

Phenols are compounds of the general formula ArOH, where Ar is a phenyl, a substituted pheuyl, or oue of the other aryl groups, e.g. uaphthyl. Phenols differ from alcohols in having the —OH group attached directly to au aromatic riug. Hydroxyheuzene, the simplest member of the phenols, is generally referred to as phenol. 

From aryl halide 110 From alcohol 156 Protection 100, 101, 144 Amino acid from hydroxy acid 40 Amphidinolide synthesis 50,94 Anatoxin synthesis 82 Aromatic ring construction 171,191 Aromatic ring substitution 10,18,19,21, 48, 54, 65,69, 104, 108, 110, 111, 120, 122,138, 149, 164, 171, 174, 175, 190,205... 

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