Reductive Desulfurization of Thioamides to Amines by Catalytic Hydrogen Transfer Reaction

Introduction Reductive desulfurization of thioamides to amines is one of the methods to prepare amines and is generally achieved by a) Zn in acid, b) sodium or aluminum amal- gams, c) lithium alumminium hydride, d) Raney Ni and e) electrolytic reduction. These methods are not very convenient to be operated and some need more complex instrument. Here is reported the reductive desulfurization of thioamides to amines by catalytic hydrogen transfer reaction(CHT).

Carbon coated LaFe_(0.92)Pd_(0.08)O_(3) composites for catalytic transfer hydrogenation:Balance in the ability of substrates adsorption and conversion

Catalytic transfer hydrogenation(CTH)is a green and efficient pathway for selective hydrogenation of unsaturated aldehydes and ketones.However,managing the abilities of solid catalysts to adsorb substrates and to convert them into desired products is a challenging task.Herein,we report the synthesis of carbon coated LaFe_(0.92)Pd_(0.08)O_(3) composites(LFPO-8@C)for CTH of benzaldehyde(BzH)into benzyl alcohol(BzOH),using isopropanol(IPA)as hydrogen source.The coating with carbon improves the ability to adsorb/transfer reactants from solution to active sites,and the doping of Pd2+at Fe3+site strengthens the ability of LaFeO_(3) to convert BzH into BzOH.A balanced point between them(i.e.,abilities to adsorb BzH and to convert BzH into BzOH)is obtained at LFPO-8@C,which exhibits a BzOH formation rate of 3.88 mmol·gcat^(-1)·h^(-1) at 180℃ for 3 h,which is 1.50 and 2.72 times faster than those of LFPO-8 and LaFeO_(3)@C.A reaction mechanism is proposed,in which the acidic sites(e.g.,Fe^(4+),oxygen vacancy)are used for the activation of C=O bond of BzH and O-H bond of IPA,and the basic sites(e.g.,lattice oxygen)for the activation ofα-H(O-H)bond of IPA.

Synthesis of ternary magnetic nanoparticles for enhanced catalytic conversion of biomass-derived methyl levulinate into γ-valerolactone

Conversion of levulinic acid and its esters into versatile y-valerolactone(GVL)is a pivotal and challenging step in biorefineries,limited by high catalyst cost,the use of hydrogen atmosphere,or tedious catalyst preparation and recycling process.Here we have successfully synthesized a ternary magnetic nanoparticle catalyst(Al_(2)O_(3)-ZrO_(2)/Fe_(3)O_(4)(5)),over which biomass-derived methyl levulinate(ML)can be quantitively converted to GVL with an extremely high selectivity of>99%and yield of-98%in the absence of molecular hydrogen.Al_(2)O_(3)-ZrO_(2)/Fe_(3)O_(4)(5)incorporates simultaneously inexpensive alumina and zirconia onto magnetite support by a facile coprecipitation method,giving rise to a core-shell structure,welldistributed acid-base sites,and strong magnetism,as evidenced by the X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),scanning electron microscopy(SEM),transmission electron microscopy(TEM),high-angle annular dark-field scanning-TEM(HAADF-STEM),SEM-energy dispersive Xray spectroscopy(SEM-EDX),temperature-programmed desorption of ammonia(NH3-TPD),temperature-programmed desorption of carbon dioxide(CO_(2)-TPD),pyridine-adsorption infrared spectra(Py-IR),and vibrating sample magnetometry(VSM).Such characteristics enable it to be highly active and easily recycled by a magnet for at least five cycles with a slight loss of its catalytic activity,avoiding a time-consuming and energy-intensive reactivation process.It is found that there was a synergistic effect among the metal oxides,and the high efficiency and selectivity originating from such synergism are evidenced by kinetic studies.Furthermore,a reaction mechanism regarding the hydrogenation of ML to GVL is proposed by these findings,coupled with gas chromatography-mass spectrometry(GC-MS)analysis.Accordingly,this readily synthesized and recovered magnetic nanocatalyst for conversion of biomassderived ML into GVL can provide an eco-friendly and safe way for biomass valorization.

Catalytic transfer hydrogenation of biomass-derived furfural to furfuryl alcohol with formic acid as hydrogen donor over CuCs-MCM catalyst

Catalytic transfer hydroge nation(CTH)of furfural(FF)to furfu ryl alcohol(FFA)has received great intere st in recent years.He rein,Cu-Cs bimetallic supported catalyst,CuCs(2)-MCM,was developed for the CTH of FF to FFA using formic as hydrogen donor.CuCs(2)-MCM achieved a 99.6%FFA yield at an optimized reaction conditions of 170℃,1 h.Cu species in CuCs(2)-MCM had dual functions in catalytically decomposing formic acid to generate hydrogen and hydrogenating FF to FFA.The doping of Cs made the size of Cu particles smaller and improved the dispersion of the Cu active sites.Impo rtantly,the Cs species played a favorable role in enhancing the hydrogenation activity as a promoter by adjusting the surface acidity of Cu species to an appropriate level.Correlation analysis showed that surface acidity is the primary factor to affect the catalytic activity of CuCs(2)-MCM.

New Chiral Ligand N-Toluenesulfonyl-2,2′-dimethoxy-6,6′-diaminobiphenyl for Catalytic Asymmetric Transfer Hydrogenation of Ketones

A new chiral ligand N p toluenesulfonyl 2,2′ dimethoxy 6,6′ diaminobiphenyl (Ts DMBDPPA) was prepared from 2,2′ dimethoxy 6,6′ diaminobiphenyl via N tosylation. Its Ru(II) complex was effective catalysts for catalytic asymmetric transfer hydrogenation of aromatic ketones (with ee 's up to 69.3%).

An Efficient Method for α-Alkylation of γ-Butyrolactone

This paper provides a simple, convenient and mild condition method for -alkylation of g-butyrolactone. Three types of (E)-a-alkenyl-g-butyrolactone compounds were synthesized by condensation of corresponding aldehydes and g-butyrolactone, using MeONa and EtONa as base. Then the a-alkyl-g-butyrolactones were gained by reducing the former alkenyl compounds through catalytic transfer hydrogenation under Pd/C catalyst with sodium hypophosphite at room temperature.

Porous Hafnium-Containing Acid/Base Bifunctional Catalysts for Efficient Upgrading of Bio-Derived Aldehydes

Novel organic-inorganic hybrids were synthesized by using HfCl 4 and organic ligand 1H-pyrrole-2,5-dicarboxylic acid(PDCA)via a simple hydrothermal method.The as-prepared Hf-PDCA were characterized by various techniques,such as electron microscope,N_(2) adsorption/desorption,and X-ray photoelectron spectroscopy.Among them,the porous and nitrogen-containing Hf-PDCA as heterogeneous acid/base bifunctional catalyst was then applied to the catalytic hydrogenation of furfural to produce furfuryl alcohol(FFA).It exhibited excellent catalytic performance,with high conversion(98.8%)and selectivity(98.5%)by using 2-propanol as hydrogen source under a relatively mild condition.Moreover,the Hf-PDCA has strong stability and durability,and can be recovered after the catalyst reaction.In addition,the Hf-PDCA as catalyst can be extended to fabricate corresponding alcohols by catalytic conversion of other biomass derived aldehydes.