102-86-3Relevant articles and documents
Reaction of aliphatic amines with 49% formic acid. 1-hexylamine, di-1-hexylamine, N,N-dimethyl-1-hexylamine, 1-dodecylamine, N,N-dimethyl-1-dodecylamine and N,N-dimethyl-1-butylamine
Katritzky, Alan R.,Parris, Roslyn L.,Ignatchenko, Elena S.,Allin, Steven M.,Siskin, Michael
, p. 59 - 65 (1997)
Two primary amines, 1-hexylamine 2, 1-dodecylamine 19, one secondary amine, di-1-hexylamine 18, and three tertiary amines, N,N-dimethyl-1-hexylamine 6, N,N-dimethyl-1-butylamine 3, and N,N-dimethyl-1-dodecylamine 22 were each heated at 150°C, 250°C or 350°C with 49% aqueous formic acid for varying periods of time. The aliphatic primary amines underwent easy N-formylation and subsequent reduction to give N-methyl- and N,N-dimethylalkylamines. Especially at higher temperatures, other reactions intervened including elimination of NH3 to the corresponding alkenes followed by partial double bond isomerization. Tertiary amines were more reactive at higher temperatures undergoing hydrolysis and reductive cleavages to secondary and primary amines, which subsequently followed the reaction sequences seen for primary amines. This series of saturated amines showed none of the cleavage into smaller fragments that was observed in the reductive alkylation of pyridine and 4-methylpyridine to a series of N-alkylpiperdines. This result reinforces the bis-aza-retro-Aldol-fragmentation mechanism postulated for the formation of the N-alkylpiperidines. Johann Ambrosius Barth 1997.
Dramatic Effect of the Specific Solvation on the Reactivity of Quaternary Ammonium Fluorides and Poly(hydrogen fluorides), (HF)n*F-, in Media of Low Polarity
Landini, Dario,Maia, Angelamaria,Rampoldi, Alessandro
, p. 328 - 332 (1989)
A quantitative study of how the intrinsic reactivity (nucleophilicity and basicity) of the fluoride anion of hexyl4N+F- is affected in solvents of low polarity by the specific solvation of a limited number of water molecules has been performed.The nucleophilicity enhancement is extrapolated to be about 3 orders of magnitude by reducing the specific hydration n of the anion from 8.5 to 0.Such enhancement is much higher (ca100 times) than that obtained, under the same conditions, by dehydrating the other halides.The nucleophilicity scale of anhydrous anions found,F- >> Cl- > Br- > I-, reflects those well-known in dipolar aprotic solvents and in the gas phase.Comparison in the same hydration range shows that the basicity of the fluoride anion is much more affected by specific solvation than is its nucleophilicity.Extension of this study to quaternary ammonium poly(hydrogen fluorides) Q+(HF)n*F-, where n = 1, 2, provides the following reactivity scale: F- >> HF2- > H2F3-.The increasing stabilization of F- anion, by interaction with hydrogen fluoride in the sequence F- - -, accounts for the much lower reactivity observed in the case of poly(hydrogen fluorides) with respect to that of the hypothetical anhydrous fluoride (F- : HF2- : H2F3- = 8.5*105 : 1.2*102 : 1).This also explains the different sensitivity of these anions to the specific hydration which decreases in the same order: F- >> HF2- > H2F3-.
Amination of 1-hexanol on bimetallic AuPd/TiO2 catalysts
Ball, Madelyn R.,Wesley, Thejas S.,Rivera-Dones, Keishla R.,Huber, George W.,Dumesic, James A.
, p. 4695 - 4709 (2018)
AuPd/TiO2 catalysts, synthesized using controlled surface reactions, are active for the gas-phase amination of 1-hexanol using ammonia. The bimetallic active sites for these catalysts have been characterized using CO chemisorption and XAS techniques, and the absence of monometallic Pd species in the AuPd catalysts was confirmed using UV-vis and STEM-EDS analysis. The bimetallic catalysts exhibit synergy between Au and Pd, as the rate of hexanol conversion increases from 8.7 μmol ks-1 (μmol total Pd)-1 over Pd/TiO2 to up to 42 μmol ks-1 (μmol total Pd)-1 over AuPd/TiO2 with a Pd/Au atomic ratio of 0.06. The rate of hexanol conversion is also enhanced with respect to Au content, with a 5-fold increase in the total Au-normalized rate from Au/TiO2 to AuPd0.67/TiO2. As Pd is added to Au/TiO2 in increasing quantities, the production rate of primary species (i.e., hexylamine and hexanenitrile) is preferentially increased. The rate of dihexylamine production increases to a lesser extent, while trihexylamine formation remains relatively constant across Pd loadings. Moreover, trihexylamine, which cannot be formed via the condensation of dihexylamine and hexanol, is shown to be produced via the secondary aldimine, N-hexylidene hexylamine. The AuPd bimetallic catalysts also exhibit reduced hydrogenolysis activity compared to monometallic Pd/TiO2.
Oxidant-free conversion of cyclic amines to lactams and H2 using water as the oxygen atom source
Khusnutdinova, Julia R.,Ben-David, Yehoshoa,Milstein, David
, p. 2998 - 3001 (2014)
Direct conversion of cyclic amines to lactams utilizing water as the only reagent is catalyzed by pincer complex 2. In contrast to previously known methods of amine-to-amide conversion, this reaction occurs in the absence of oxidants and is accompanied by liberation of H2, with water serving as a source of oxygen atom. Formation of a cyclic hemiaminal intermediate plays a key role in enabling such reactivity. This represents an unprecedented, conceptually new type of amide formation reaction directly from amines and water under oxidant-free conditions.
Amination of aliphatic alcohols with urea catalyzed by ruthenium complexes: effect of supporting ligands
Dindar, Sara,Nemati Kharat, Ali
, (2020/09/02)
In the present study, ruthenium-catalyzed amination of alcohols by urea as a convenient ammonia carrier in the presence of free diphosphine ligands has been described. A number of ruthenium-phosphine complexes have been studied among which, [(Cp)RuCl(dppe)] was found as an efficient catalyst for alcohol amination reaction. The crystal structures of two new half-sandwich ruthenium complexes, [(Cp)RuCl(dppe)] and [(C6H6)RuCl2(PHEt2)], were determined by X-ray crystallographic analysis. Also the effect of using different supporting phosphines, ratio of raw materials and reaction temperature on conversion and selectivity was investigated. Under optimum reaction conditions high conversion (98percent) and chemo-selectivity toward secondary amines were obtained.
Selective Synthesis of Secondary and Tertiary Amines by Reductive N-Alkylation of Nitriles and N-Alkylation of Amines and Ammonium Formate Catalyzed by Ruthenium Complex
Alshakova, Iryna D.,Nikonov, Georgii I.
, p. 5370 - 5378 (2019/06/14)
A new ruthenium catalytic system for the syntheses of secondary and tertiary amines via reductive N-alkylation of nitriles and N-alkylation of primary amines is proposed. Isomeric complexes 8 catalyze transfer hydrogenation and N-alkylation of nitriles in ethanol to give secondary amines. Unsymmetrical secondary amines can be produced by N-alkylation of primary amines with alcohols via the borrowing hydrogen methodology. Aliphatic amines were obtained with excellent yields, while only moderate conversions were observed for anilines. Based on kinetic and mechanistic studies, it is suggested that the rate determining step is the hydrogenation of intermediate imine to amine. Finally, ammonium formate was applied as the amination reagent for alcohols in the presence of ruthenium catalyst 8. Secondary amines were obtained from primary alcohols within 24 hours at 100 °C, and tertiary amines can be produced after prolonged heating. Secondary alcohols can only be converted to secondary amines with moderate yield. Based on mechanistic studies, the process is suggested to proceed through an ammonium alkoxy carbonate intermediate, where carbonate acts as an efficient leaving group.
