From Benzene and Derivatives

By far the preponderance of the 3400 kt of current worldwide phenolic resin production is in the form of phenol-formaldehyde (PF) reaction products. Phenol and formaldehyde are currently two of the most available monomers on earth. About 6000 kt of phenol and 10,000 kt of formaldehyde (100% basis) were produced in 1998 [55,56]. The organic raw materials for synthesis of phenol and formaldehyde are cumene (derived from benzene and propylene) and methanol, respectively. These materials are, in turn, obtained from petroleum and natural gas at relatively low cost ([57], pp. 10-26 [58], pp. 1-30). Cost is one of the most important advantages of phenolics in most applications. It is critical to the acceptance of phenolics for wood panel manufacture. With the exception of urea-formaldehyde resins, PF resins are the lowest cost thermosetting resins available. In addition to its synthesis from low cost monomers, phenolic resin costs are often further reduced by extension with fillers such as clays, chalk, rags, wood flours, nutshell flours, grain flours, starches, lignins, tannins, and various other low eost materials. Often these fillers and extenders improve the performance of the phenolic for a particular use while reducing cost. 

It was then cooled, washed with water, dried over sodium sulfate and evaporated to dryness. The residue was crystallized from benzene and pentane to give 138.5 g of the dicyclobutane-carbonyl derivative, melting point about 112°C (dec.). 

D. H. Phillips, DNA adducts Identification and biological significance, in DNA Adducts Derived From Safrole, Estragole and Related Compounds, and From Benzene and Its Metabolites, Vol. 125 (Eds. K. Hemminki, A. Dipple, D. E. G. Shuker, F. F. Kadlubar, D. Segerback, H. Bartsch). lARC Scientific Publications, Lyon, 1994, P 131. 

Stabilized carbocations can be generated from allylic and benzylic alcohols by reaction with Sc(03SCF3)3 and results in formation of alkylation products from benzene and activated derivatives.39... 

There is a long history of the preparation of explosive solids or oils from interaction of diazonium salts with solutions of various sulfides and related derivatives. Such products have arisen from benzene- and toluene-diazonium salts with hydrogen, ammonium, or sodium sulfides [1,5] 2- or 3-chlorobenzene-, 4-chloro-2-methylbenzene-, 2- or 4-nitrobenzene- or 1- or 2-naphthalene-diazonium solutions with hydrogen sulfide, sodium hydrogen sulfide or sodium mono-, di- or poly-sulfides [l]-[4,7], 4-Bromobenzenediazonium solutions gave with hydrogen sulfide at -5°C a product which exploded under water at 0°C [2], and every addition of a drop of 3-chlorobenzenediazonium solution to sodium disulfide solution... 

A well understood case is that of quinoline reaction at position 2 is kinetically favored as compared with reaction at position 4, but the adduct from the latter is thermodynamically more stable. This situation, where the site of attack leading to the more stable adduct is the y position, is analogous with those regarding the formation of Meisenheimer adducts from benzene and pyridine derivatives and RCT nucleophiles. Presumably, with quinoline kinetic control favors the position that is more strongly influenced by the inductive effect of the heteroatom. The fact that position 2 of quinoline is the most reactive toward nucleophilic reagents is probably related to the lower 71-electron density at that position.123 However, the predominance of the C-4 adduct at equilibrium can be better justified by the atom localization energies for nucleophilic attachment at the different positions of quinoline. Moreover, both 7t-electron densities and atom localization energies indicate position 1 of isoquinoline to be the most favored one for nucleophilic addition. 

In this chapter, we will be concerned with the ortho photocycloaddition of arenes to the benzene ring. This implies that photocycloadditions to larger aromatic systems and to heterocyclic aromatic molecules will not be discussed. The photoadditions of alkynes to benzene and derivatives of benzene, however, are included in this review. The material is organized in sections, according to the pathway that is followed from the ground state of the addends to the ortho photocycloadducts. 

Diaryl Tellurium 3-Mercaptopropanoate3 To a solution of 0.05 mol of the diaryl tellurium oxide in 50 ml anhydrous toluene are added 0.05 mol 3-mercaptopropanoic acid. The stirred mixture is refluxed for 3 h. Water is removed by azeotropic distillation and collected in a Dean-Stark trap. The toluene is evaporated. The diphenyl derivative is purified by preparative thin-layer chromatography and column chromatography with toluene as mobile phase. The ethoxyphcnyl derivative is recrystallized from benzene and hexane. Compounds thus prepared include ... 

Each of these groups of substances may be sub-divided into four series The first three of these comprise the aliphatic compounds derived from methane (series I), ethane (series II) and propane (series III). The fourth series comprises the aromatic compounds derived from benzene and its homologues. 

This is the simplest case of the reaction but it has been mostly used in the synthesis of higher members of the unsaturated acid series, e.g., the nine carbon acid, nonylenic acid, which is prepared from the seven carbon aldehyde known as oenanthylic aldehyde, or oenanthol, obtained from castor oil. Even more important than its application in the synthesis of higher acids of the ethylene series is the use of the reaction in the synthesis of aromatic unsaturated cLcids derived from benzene and containing an unsaturated side chain (see cinnamic acid. Part II). The reaction is known as the Perkin Synthesis or as the Perkin-Fittig Synthesis from the men who suggested and explained it. 

The hydrogen atom in the ortho position to the carbonyl group unites with the hydroxyl group of the carboxyl to effect the ring closure. The preparation of o-benzoylbenzoic acid from benzene and phthalic anhydride (Experiment 63) and the dehydration of this keto acid to anthraquinone considered in the present experiment illustrate the building up of polynuclear compounds from simpler benzene derivatives. 

Derivation From chlorobenzene Grignard reagent and methyltrichlorosilane or from benzene and me-thyldichlorosilane. 

Derivation From benzene and propylene by use of aluminum chloride and hydrochloric acid to yield cumene, which is then dehydrogenated. 

A feature of the book is the introduction of directions for the preparation of certain compounds on a very small scale. Students often acquire the habit of careless work in the laboratory practice in organic chemistry. Preparation-work on the small scale serves to counteract this effect and to develop a technique that is valuable. Such work is often necessary in the identification of unknown compounds when a small amount only of the substance is available. In many cases a crystalline derivative whose melting-point can be determined, can be prepared in a pure condition from but two or three drops of a substance. Among the examples of work of this kind which are given are the preparation of acetanilide from acetic acid, glyceryl tribenzoate from glycerol, dinitrobenzene from benzene, and dibenzalacetone from acetone. In order to facilitate such work, a section in the first chapter is devoted to a consideration of the technique used in the manipulation of small quantities of substances. 

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