pH-responsive gelatin polymer-coated silica-based mesoporous composites for the sustained-release of indomethacin.

This paper prepared drug-loaded mesoporous silica composites with a pH-responsive type. These composites were prepared by using three-dimensional caged silica (SBA-16) as the carrier, 3-aminopropyl trimethoxysilane (APTMS) as the silane coupling agent, and indomethacin (IMC) as the loaded drug, respectively. The drug-loaded precursor NH2-SBA-16@IMC was prepared by solution diffusion adsorption. Finally, the pH-responsive drug-loaded composites NH2-SBA-16@IMC@GA were synthesized by wrapping the NH2-SBA-16@IMC with a condensation polymer of gelatin and glutaraldehyde. The composition and structure of the drug-loaded composites were characterized by FT-IR, XRD, TG, SEM, TEM, and N2 adsorption-desorption. The in vitro simulated release performance of the drug-loaded composites was investigated at 37 °C under three pH conditions. The results show that the NH2-SBA-16@IMC@GA can be released in response to specific pH environment, which can effectively control the release speed of the indomethacin.

Improving the catalytic and mechanical performance of alginate catalyst through functionalization by aminopolycarboxylic acids.

Biomass-based aerogel catalysts have attracted extensive attention due to their high surface aera, continuous porous and environmental friendliness. However, their catalytic activity and mechanical strength are not satisfied for industrial applications. In this work, to solve the above two issues, a new kind of graphene oxide enhancediminodiacetic acid-functionalized Cu-cross-linked alginate (GO-Cu-SA-IDA) aerogel composites were prepared. The physicochemical property of the prepared alginate aerogel composites was characterized systematically, and their catalytic activities were studied in the hydroxylation of phenol. Results illustrated that compared with Cu-SA aerogels (∼16 %), the amount of loaded copper ion which played as the active sites in GO-Cu-SA-IDA aerogel composite was increased by 2 times (32.2 %). In addition, the mechanical strength of GO-Cu-SA-IDA was increased by 10 times. After functionalization, both the catalytic activity and mechanical strength of prepared alginate aerogel composites were enhanced successfully. In addition, the catalyst had been recycled five times with only 5.8 % loss of its catalytic activity, which provided a desirable material for next generation of catalysts.

Alginate-based aerogels with double catalytic activity sites and high mechanical strength.

Aerogel nanocomposites from biomass are one of the attractive emerging materials in the field of material chemistry and catalyst industry, but their lower catalytic efficiency and mechanical performance have limited their wide range applications. In this work, alginate-based aerogels with perfect catalytic performance and great mechanical strength were prepared through incorporating graphene oxide (GO) and SiO2 via a simple one-pot reaction. GO played as the second catalytic activity sites and endowed the aerogels the perfect catalytic performance (conversion of phenol reached 90.1 % in phenol hydroxylation reaction). Meanwhile, SiO2 and GO could improve the particle compressive strength of the aerogel to 36.0 kg/cm2. This alginate-based aerogel provides a novel and environmentally friendly catalyst for next generation catalytic industry.

Preparation and catalytic performance of alginate-based Schiff Base.

As a biomass polymer, alginate-based material has drawn considerable attention and been applied in many fields. However, the research on alginate-based Schiff Base metal complex is scarce. Herein, a novel alginate-based Schiff Base Cu (II) complex was prepared via oxidation and imidization of alginate by periodate and organic amine, respectively. In additon, their catalytic performance in phenol hydroxylation reaction was investgated. Results illustrated that degree of oxidation had significant influence on metal loaded content. Compared with alginate, the alginate-based Schiff Base has more reactive groups, and can stablize more Cu cations which endowed their better catalytic activities.

Photocatalytic process of simultaneous desulfurization and denitrification of flue gas by TiO2-polyacrylonitrile nanofibers.

TiO2 nanoparticles were successfully fabricated on electrospun polyacrylonitrile (PAN) nanofibers via the coupling of electrospinning and hydrothermal pathway. A straightforward photocatalysis oxidation process has been developed for simultaneous desulfurization and denitrification of flue gas using the TiO2-PAN photocatalyst. Also, the influences of some important operating parameters, such as titanium loading content of catalyst, flue gas humidity, flue gas flow, and inlet flue gas temperature on removal efficiencies of SO2 and NO were investigated. The results demonstrated that removal efficiencies of 99.3% for SO2 and 71.2% for NO were attained under the following optimal experiment conditions: titanium loading content, 6.78 At %; gas flow rate, 200 mL/min; flue gas humidity, 5%; inlet flue gas temperature, 40 °C. Furthermore, the presumed reaction mechanism of SO2 and NO removal using TiO2-PAN photocatalyst under UV light was proposed.

Epoxidation of alkenes catalyzed by phenyl group-modified, periodic mesoporous organosilica-entrapped, dimeric manganese-salen complexes.

A series of reusable, recoverable, diamine-bridged dimeric manganese-salen complexes were prepared by the encapsulation of homogeneous dimeric Mn(salen) complexes into nanocages of a 3D periodic mesoporous organosilica (PMO) support followed by silylation of the support with organosilane. The composition, structure, morphology, and textural properties of the prepared PMO-entrapped dimeric Mn(salen) complexes were characterized, and their catalytic performances were tested in the epoxidation of alkenes (styrene, cyclohexene, and 1-phenylcyclohexene), with NaClO as an oxygen source and 4-phenylpyridine-N-oxide as an axial ligand. Furthermore, the influences of the textural and morphological properties of the entrapped dimeric Mn(salen) complexes and the key reaction parameters on the catalytic activity and selectivity are discussed. Finally, the reusability of the supported dimeric Mn(salen) complexes was evaluated over three catalytic runs.

Mixed phase titania nanocomposite codoped with metallic silver and vanadium oxide: new efficient photocatalyst for dye degradation.

Titania nanocomposite codoped with metallic silver and vanadium oxide was prepared by a one-step sol-gel-solvothermal method in the presence of a triblock copolymer surfactant (P123). The resulting Ag/V-TiO(2) three-component junction system exhibited an anatase/rutile (weight ratio of 73.8:26.2) mixed phase structure, narrower band gap (2.25 eV), and extremely small particle sizes (ca. 12 nm) with metallic Ag particles well distributed on the surface of the composite. The Ag/V-TiO(2) nanocomposite was used as the visible- and UV-light-driven photocatalyst to degrade dyes rhodamine B (RB) and coomassie brilliant blue G-250 (CBB) in an aqueous solution. At 1.8% Ag and 4.9% V doping, the Ag/V-TiO(2) system exhibited the highest visible- as well as UV-light photocatalytic activity; additionally, the activity of the three-component system exceeded that of Degussa P25, pure TiO(2), single-doped TiO(2) system (Ag/TiO(2) or V-TiO(2)) as well as P123-free-Ag/V-TiO(2) codoped system. The reasons for this enhanced photocatalytic activity were revealed.

Temperature-controlled synthesis of substituted pyridine derivatives via the [5C + 1N] annulation of 1,1-bisalkylthio-1,4-pentanedienes and ammonium acetate.

A novel temperature-controlled one-pot synthesis of substituted pyridine derivatives via [5C + 1N] annulation of 1,1-bisalkylthio-1,4-pentanedienes and ammonium acetate is developed, and possible mechanisms leading to the divergent formation of the two types of pyridines are discussed.

BF3.Et2O-catalyzed direct carbon-carbon bond formation of alpha-EWG Ketene-(S,S)-acetals and alcohols and synthesis of unsymmetrical biaryls.

A highly efficient BF3.OEt2-catalyzed formal dehydration C-C coupling reaction between readily available alpha-EWG ketene-(S,S)-acetals and various alcohols via direct substitution of the hydroxy group in alcohols has been developed. On the basis of this C-C coupling reaction, a series of alkylated alpha-EWG ketene-(S,S)-acetals and functionalized 1,4-pentanedienes were prepared in high to excellent yields and the unsymmetrical biaryls were synthesized in good yields from the generated 1,4-pentanedienes and nitroalkanes through a one-pot annulation-aromatization process.