Template Assisted Synthesis of Nanocrystalline Sulfated Titania: Active and Robust Catalyst for Regioselective Ring Opening of Epoxide with Aniline and Kinetic Modeling

Abstract

The regioselective ring opening of epoxides with aniline affording β-amino alcohols is commercially important. A variety of heterogeneous catalysts such as fuel lean sulfated zirconia (FLSZ), UDCaT-5, 20%Cs 2.5 H 0.5 PW 12 /K-10 clay, Hβ-zeolite, nanocrystalline sulfated titania (NCST), and titania were evaluated in the reaction of epichlorohydrin with aniline. A nanocrystalline sulfated titania (NCST) catalyst, the most active and selective, was prepared by the sol−gel method using poly(vinyl alcohol) (PVA) as a green template and functionalized using sulfuric acid. The sulfate content was in the range 4.1% (w/w). It was well characterized using TEM, FT-IR, XRD, NH 3 -TPD, N 2 -BET surface area, and TGA. The effects of various parameters such as speed of agitation, molar ratio, catalyst loading, and temperature using the NCST catalyst were investigated in the reaction of epichlorohydrin with aniline to achieve good yields and excellent regioselectivity at 60 °C and 0.01 g/cm 3 catalyst loading. The catalyst was effectively recycled for five consecutive cycles without any significant loss in its activity. Furthermore, a reaction mechanism was proposed to deduce a kinetic model which was validated against experimental data. The entire process is green. The protocol was extended to the reaction of several epoxides and amines over NCST to make corresponding β-amino alcohols.

Sulfated Titania (TiO2‐SO42−) as an Efficient Catalyst for Organic Synthesis: Overarching Review from 2000 to 2021

“…The β‐amino alcohols are versatile intermediates in agrochemical, and pharmaceutical industries and are also involved in the formation of biologically active molecules. They have been prepared via the ring‐opening of epoxides with amines by Yadav et al [103,104] . using nanocrystalline sulfated titania (NCST) with regioselectivity (Scheme 55).…”

“…[56] in the formation of biologically active molecules. They have been prepared via the ring-opening of epoxides with amines by Yadav et al [103,104] using nanocrystalline sulfated titania (NCST) with regioselectivity (Scheme 55). NCST catalytic activity was examined with Hβ-zeolite, zirconia-based catalyst (UDCaT-5), 20 % cesium-substituted dodecatungstophosphoric acid (Cs 2.5 H 0.5 PW 12 /K-10 clay), titania and fuel-lean sulfated zirconia (FLSZ).…”

Catalyst Free, Nitromethane Assisted Facile Ring Opening of Epoxide with Less Reactive Aromatic Amines

“…[3] The β-amino alcohols are vital intermediates in medicinal chemistry and have been widely implemented for the synthesis of various biologically active compounds. [4][5] One of the most important scaffolds of β-amino alcohol is hydroxyethylamine (HEA) [6] that has been extensively explored as synthon for the discovery of antimalarials [7][8] , anti-fungal [9] , HIV protease inhibitors [10] and anti-Alzheimer agents [11][12] etc. In literature, quite a few routes are available for synthesis of HEA that involves the nucleophilic ring opening of epoxide with amines under conventional heating or microwave irradiation.…”

Graphene‐Oxide‐Supported SO3H‐Functionalized Imidazolium‐Based Ionic Liquid: Efficient and Recyclable Heterogeneous Catalyst for Alcoholysis and Aminolysis Reactions

“…Due to their versatility and reactivity towards a large range of nucleophiles such as alcohols, amines, and thiols many bifunctional compounds of industrial relevance are synthesized. β‐Alkoxy alcohols and β‐amino alcohols are key intermediates in the synthesis of a wide range of biologically active synthetic and natural products, chiral auxiliaries for asymmetric synthesis and unnatural amino acids . β‐Alkoxy and β‐amino alcohols are synthesized by alcoholysis and aminolysis of epoxides, respectively.…”