Propyl reaction

Within the bivalent cation-exchanged Y series, the order Ca, Mg, Cd > Sr > Ba has been observed 125,127) in benzene propylation at 250-300 . Activity of the CaY for the propylation reaction reached a sharp peak in activity when 50% of the Na+ ions had been replaced by Ca++ 125). This increase in activity corresponds with the increasing occupation by Ca++ of the Su sites in zeolite Y at higher degrees of Ca++ exchange, as predicted by Pickert et ai. 40). 

Recently [15] we have measured the alkyl group effect in this energy disposal behaviour, and the result is shown in Fig. 4 where data for the methyl, ethyl and propyl reactions are displayed. Note that whereas Fp, the fraction of the total energy that appears in translational energy of the products, is about 0.6 (0.5) for the methyl (ethyl) reaction, it reduces to 0.3 for the propyl case. This enhancement in... 

The inflammable solvents most frequently used for reaction media, extraction or recrystallisation are diethyl ether, petroleum ether (b.p. 40-60° and higher ranges), carbon disulphide, acetone, methyl and ethyl alcohols, di-Mo-propyl ether, benzene, and toluene. Special precautions must be taken in handling these (and other equivalent) solvents if the danger of Are is to be more or less completely eliminated. It is advisable to have, if possible, a special bench in the laboratory devoted entirely to the recovery or distillation of these solvents no flames are permitted on this bench. 

P -f lOROH -f 5Br, — 2H3PO, -f lORBr -f 2H,0 The reaction is of general application with primary alcohols (n propyl to n hexadecyl) the yields are over 90 per cent, of the theoretical, but with secondary alcohols the yields are 50-80 per cent. in the latter case a small quantity of high boiling point by-product is also formed which can, however, be readily removed by fractional distillation. The reaction is conveniently carried out in a special all glass apparatus. 

Ethyl acetate. Use 58 g. (73-5 ml.) of absolute ethyl alcohol, 225 g. of glacial acetic acid and 3 g. of concentrated sulphuric acid. Reflux for 6-12 hours. Work up as for n-propyl acetate. B.p. 76- 77°. Yield 32 g. Much ethyl acetate is lost in the washing process. A better yield may be obtained, and most of the excess of acetic acid may be recovered, by distilhng the reaction mixture through an efficient fractionating column and proceeding as for methyl acetate. 

If desired, the alcohol may be identified as the 3 5-dinitrobenzoate (Section 111,27) it is then best to repeat the experiment on a larger scale and to replace the dilute hydrochloric acid by dilute sulphuric acid. It must, however, be pointed out that the reaction is not always so simple as indicated in the above equation. Olefine formation and rearrangement of the alcohol sometimes occur thus n-prop3 lamine yields n-propyl alcohol, isopropyl alcohol and propylene. 

The ketones are readily prepared, for example, acetophenone from benzene, acetyl chloride (or acetic anhydride) and aluminium chloride by the Friedel and Crafts reaction ethyl benzyl ketones by passing a mixture of phenylacetic acid and propionic acid over thoria at 450° and n-propyl- p-phenylethylketone by circulating a mixture of hydrocinnamic acid and n-butyric acid over thoria (for further details, see under Aromatic Ketones, Sections IV,136, IV,137 and IV,141). 

The formation of alkylbenzenes, largely free from unaaturated compounds, provides another interesting application of organosodium compounds. Thus pure M-butylbenzene is readily obtained in good yield from benzyl sodium and n-propyl bromide. Benzyl-sodium is conveniently prepared by first forming phenyl-sodium by reaction between sodium and chlorobenzene in a toluene medium, followed by heating the toluene suspension of the phenyl-sodium at 105° for about 35 minutes ... 

The last isomerization is remarkable in that the triple bond can shift through a long carbon chain to the terminus, where it is fixed as the (kinetically) stable acetylide. The reagent is a solution of potassium diami no-propyl amide in 1,3-di-aminopropane. In some cases alkali metal amides in liquid ammonia car also bring about "contra-thermodynamic" isomerizations the reactions are successful only if the triple bond is in the 2-position. 

Substitution can take place by the S l or the 8 2 mechanism elimination by El or E2 How can we predict whether substitution or elimination will be the principal reac tion observed with a particular combination of reactants The two most important fac tors are the structure of the alkyl halide and the basicity of the anion It is useful to approach the question from the premise that the characteristic reaction of alkyl halides with Lewis bases is elimination and that substitution predominates only under certain special circumstances In a typical reaction a typical secondary alkyl halide such as iso propyl bromide reacts with a typical Lewis base such as sodium ethoxide mainly by elimination... 

Diethyl Ketone. Diethyl ketone [96-22-0] (3-pentanone) is isomeric with methyl / -propyl ketone (2-pentanone), which has similar solvent and physical properties. Diethyl ketone is produced by the decarboxylation of propionic acid over Mn02—alumina (165), Zr02 (166), or Zr02 or Th02 on Ti02 (167,168). Diethyl ketone can also be produced by the hydrocarbonylation of ethylene (169—171). It is used as a solvent and a reaction intermediate. 

The Guerbet reaction can be used to obtain higher alcohols 2-propyl-1-heptanol [10042-59-8] from 1-pentanol condensation and 6-methyl-4-nonanol from 2-pentanol (80—83). Condensations with alkah phenolates as the base, instead of copper catalyst, produce lower amounts of carboxyhc acids and requke lower reaction temperatures (82,83). The crossed Guerbet reaction of 1-pentanol with methanol in the presence of sodium methoxide catalyst afforded 2-heptanol in selectivities of about 75% (84). 

According to this mechanism, the reaction rate is proportional to the concentration of hydronium ion and is independent of the associated anion, ie, rate = / [CH3Hg][H3 0 ]. However, the acid anion may play a marked role in hydration rate, eg, phosphomolybdate and phosphotungstate anions exhibit hydration rates two or three times that of sulfate or phosphate (78). Association of the polyacid anion with the propyl carbonium ion is suggested. Protonation of propylene occurs more readily than that of ethylene as a result of the formation of a more stable secondary carbonium ion. Thus higher conversions are achieved in propylene hydration. 

Silanes react with alkyllithium compounds, forming various alkylsilanes. Complete substitution is generally favored however, less substituted products can be isolated by proper choice of solvent. AH four methylsHanes, vinylsHane [7291-09-1and divinylsilane [18142-56-8] have been isolated from the reaction of SiH and the appropriate alkyllithium compound with propyl ether as the solvent (35). MethylsHane and ethyldisHane [7528-37-2] have been obtained in a similar reaction (36). 

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