Aniline, alkylation

The reactions of anilines, alkyl orthoformate, and dialkyl malonates in the presence of FeCI3 catalysts at I00-I40°C for 6 hr gave dialkyl arylaminomethylenemalonates (256) in very good yields (87M1P3 880PP93). 

Surface Alkylated dimethyl aniline, Alkylated pyridine, Heparin content,... 

The vapor-phase pyrolysis of phenyl azide yields azobenzene in 72 % yield . The pyrolysis in aniline solution leads to the production of dibenzamil , identified as an azepine by modern techniques in benzene and p-xylene, the major products are azobenzene and aniline, presumably originating from reactions of PhN in hydrocarbon solvents the thermolysis produces aniline, alkyl-anilines, azobenzene and polymer . It has been shown that aniline and iV-alkylanilines arise from triplet state nitrene reactions with the solvent. In the gas-phase thermolysis of phenyl azide at low pressures aniline and azobenzene are the major products whereas at higher pressures the formation of l-cyano-1,3-cyclopentadiene (or 2-anilino-7H-azepine in the presence of aniline) predominates . It was deduced that aniline and azobenzene arise from triplet nitrene reactions and that at high pressures, a hot singlet nitrene is formed, which undergoes intramolecular insertion to form an azocyclopropene intermediate, viz. 

AIPO4 and AlPO -metal oxide catalysts exhibited high activity and selectivity in aniline alkylation to produce N-alkylated products in a consecutive first-order reaction process. N-methylaniline was easily formed at low temperatures/contact times and converted to N,N-dimethylaniline as temperature/contact time increased. N-alkylated products remained 100 mol% at 523-623 K. At 673 K, N,N-dimethyltoluidine (p->o-) also appeared although in very small amounts. The results obtained for pyridine adsorption at 373 (weak acidic) and 573 K (medium acidic) generally agreed with catalytic activity. 

Ebenfalls Desulfurierung wird bei der Hydrogenolyse von 1,3-Benzothiazol und 2-Methyl-l,3-benzothiazol an Molybdansulfid-Katalysatoren beobachtet. Gleichzeitig findet Alkyl-Transfer statt, und cs werden neben Anilin Alkyl-aniline erhaltcn559. 

Montmorillonite is a layered smectite clay. Acid activation replaces the interlamellar cations with protons, leaches Al from octahedral layers resulting in increase of surface area, porosity and acidity. Clay is activated with a mineral acid for different time intervals. They are characterised by XRD, surface area and acidity by stepwise temperature desorption of ammonia Catalytic activity is studied on aniline alkylation reaction. 

In our earlier experiments we have found that montmorillonite KIO, a commercial acid activated clay is a good catalyst for aniline alkylation [9,10]. This has prompted us to study the effect of acid activation of clay on the reaction. 

We have studied activation of montmorillonite with mineral acid H2SO4. The effect of acid activation on structural properties of clay is interpreted in terms of XRD patterns, surface area and acidity measurement while the catalytic property is evaluated from the aniline alkylation reaction. 

Vapour phase aniline alkylation is carried out over ca. 0.5 g catalyst at 673 K and feed rate 12 cm h" g in a vertical flow reactor. N2 is used as carrier gas. Products are collected every hour for 4h and are analysed by a gas chromatograph using a column of Apiezon-L treated with 2% KOH on chromosorb 80/100 A.W. Alkylated anilines obtained are analysed to be mainly N-ethylaniline (NEA), NN diethylaniline (NNDEA) and traces of toluidine. 

Fig. 3 describes the dependence of aniline alkylation on surface area of the catalysts. Na montmorillonite is inactive for the reaction. Aniline alkylation activity reached a maximum when the surface area of the catalyst is about 130 m g Beyond this, the effect of increase in surface area on the catalytic activity is not conspicuous. Total acidity in the range 40 - 70 X 10 mmole NHsg seems to be favourable for the reaction (fig.4). 

Amongst the catalysts studied acidity in the range 40 - 70 X 10 mmole NH3 g and surface area of 130 m seem to be favourable for aniline alkylation. 

Hunter, F.D., and J. Scherzer, 1971, J. Catal. 20,246. Ikemoto, M., K. Tsutsumi and H. Takahashi, 1972, Bull. Chem. Soc. Japan 45, 1330. lone, K.G., and O.V Kikhtyanin, 1989, Reactions of electrophilic substitution on zeolite catalysts. Aniline alkylation by methanol, in Zeolites Facts, Figures and Future, eds PA. Jacobs and... 

C MAS NMR has been performed in-situ under batch conditions to investigate the mechanism of aniline alkylation with methanol on acidic H-Y and basic CsNa-Y impregnated with cesium hydroxide. On acidic zeolite H-Y, methanol reacts with zeolitic hydroxyl groups to give surface methoxy groups which, in turn, play a role as alkylating species in aniline methylation. On the basic zeolite Y, meth ol is converted into formaldehyde, which is responsible for the N-alkylation. Both on acidic and basic zeolites, N-methylaniline is the primary alkylation product. Toluidines and N-methyltoluidines are formed only on the acidic zeolite at elevated temperatures after complete conversion of methanol into N-methylaniline. 

The general expression of aniline alkyl sulfhydryl can be given as follows ... 

It was reported that aniline alkyl sulfhydryl was applied in the flotation of zinc ore of New Brocken Hill in Australia [27]. Under the condition of pH 8.2, reagent dosage 102 g/t, and no addition of CUSO4, the recovery rate of zinc and concentrate grade are, respectively, 96 and 46 %. When the concentrate grade is 50.1 %, the recovery rate of zinc becomes 80 %. The flotation performance of aniline alkyl sulfhydryl is similar to that of xanthate. 

Aniline alkyl sulfhydryl can be synthesized by adopting aniline and vinyl episulfide as raw materials. The synthetic reaction can be given by the following ... 

Bicyclic meso-N-ary aziridines are ring-opened by anilines, giving trans-1,2-diamines in the presence of a Ti(0-Bu-t)4/(l )-BlN0L catalyst in CH2Cl2." The reactions occur in yields between 65 and 96% with 57-99% ee. Lower enantioselectivities were found when electron-withdrawing and orifto-substituents were on the aniline. Alkyl amines failed to react. ESI-MS experiments indicate that the catalyst contains two titanium and two linked bis-BINOL ligands. 

Moles of Aniline Alkylating Agent (moles) Catal3Tst (moles) Solvent Tem- perature, c. Time, hours Products (% Yield) Reference ... 

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