Furan-2,5- and Furan-2,3-dicarboxylate Esters Derived from Marine Biomass as Plasticizers for Poly(vinyl chloride).

Esters of furan dicarboxylic acids (DAFs) were synthesized by a one-pot reaction between marine biomass-derived galactaric acid and bioalcohol under solvent-free conditions and were fully characterized. The catalyst amount could be reduced without loss of reaction yields using p-xylene as the material separation agent. Also, a possible mechanism was proposed for the first time. Then the properties of four DAFs as plasticizers on the poly(vinyl chloride) (PVC) matrix were investigated. The experimental results showed that DAFs exhibit competitive efficiencies of plasticization when compared to the most commercialized plasticizer, DOP. It was found that the combination of DAFs and PVC produced homogeneous smooth-surface films, indicating miscibility between them. ATR-FTIR depicted the upshift of carbonyl absorption bands after mixing with the PVC matrix, with a magnitude of at most 18-21 cm-1. TGA, DSC, and UTM data illustrated equivalent plasticization efficiencies. Due to their small molecular weights, the investigated DAFs are more volatile. However, due to bearing an oxygen atom in the aromatic furan ring, the degree of polarization of DAFs was boosted and helped inhibit leaching into the surrounding media. In brief, these synthetic compounds have promising feasibility as biobased plasticizers. Moreover, another interesting point is that the properties of furan-2,3-dicarboxylic acid derivatives were studied for the first time and herein reported.

Conversion of D-fructose to 5-acetoxymethyl-2-furfural Using Immobilized Lipase and Cation Exchange Resin.

5-Acetoxymethyl-2-furfural (AMF) was prepared from D-fructose via 1,6-diacetylfructose (DAF) through a simple two-step reaction pathway. Immobilized enzyme (Novozym 435) was found to be the best enzymatic catalyst for the trans-esterification step (yielding 94.6% DAF). In the dehydration step, while soluble H2SO4 was found to be the best acidic catalyst (yielding 86.6% AMF), we opted to utilize heterogeneous cation exchange resin (Amberlyst 15) together with recyclable industrial solvents (1,4-dioxane) for a more sustainable AMF synthesis procedure. Although the total yield of AMF was a little lower, both the enzyme and the solid acid catalyst could be recycled for five cycles without a significant loss of activity, which has a major contribution to the cost-efficient aspect of the entire process.

From lignocellulosic biomass to furans via 5-acetoxymethylfurfural as an alternative to 5-hydroxymethylfurfural.

A facile pathway to furan derivatives from lignocellulosic biomass via 5-acetoxymethylfurfural (AMF) was developed. AMF possesses advantageous properties due to its less-hydrophilic acetoxymethyl group relative to the hydroxymethyl group of 5-hydroxymethylfurfural (HMF). The hydrophobicity and chemical stability of AMF allowed practical isolation and purification to afford a highly pure product of up to 99.9 %. AMF was produced in good to excellent yields under mild conditions from 5-chloromethylfurfural (CMF) and alkylammonium acetates, both of which could be obtained directly from lignocellulosic biomass. Heterogeneous reactions with polymer-supported alkylammonium acetates were also established; this showed the feasibility of a continuous process for this pathway. AMF could be transformed into various promising furanic compounds, such as 2,5-furandicarboxylic acid (FDCA), 2,5-furandimethanol (FDM), and 5-hydroxymethyl-2-furanoic acid (HFA), in high yields.

Folic acid-tethered poly(N-isopropylacrylamide)-phospholipid hybrid nanocarriers for targeted drug delivery.

A series of temperature-responsive lipopolymers have been synthesized by bioconjugating poly(N-isopropylacrylamide)n (n = 25, 40, 60) onto three different phospholipids by the combination of reversible addition fragmentation chain transfer polymerization and azide-alkyne click reactions. To achieve the active targeting of cancer cells, folic acid (FA) has also been tethered to the resulting hybrid materials. The doxorubicin (Dox) encapsulated uniform nanocarriers (150 nm in diameter) fabricated by the self-assembly of the lipopolymers display temperature responsive controlled release. The FA receptor-mediated delivery of Dox was then assessed using KB cell lines, and the anti-cancer activity was assessed by the blocking of folic acid receptors. The FA-tethered lipopolymers showing temperature-responsiveness are advantageous for the cell-specific release of Dox, potentiating their anti-cancer activity.

Triplet-triplet annihilation upconversion in CdS-decorated SiO2 nanocapsules for sub-bandgap photocatalysis.

This study reports the first successful nanoscale encapsulation of triplet-triplet annihilation upconversion (TTA-UC) medium within a rigid silica shell using a self-assembly microemulsion process. These newly synthesized nanocapsules present a few critical advances that could be instrumental for a wide range of aqueous-based photonics applications, including photocatalysis, artificial photosynthesis, and bioimaging. The nanocapsules form a homogeneous suspension that can produce intense, diffuse UC emission in water without deoxygenation, closely resembling conventional TTA-UC processes that have been performed in deoxygenated organic solvents. The silica shell provides sites for further surface modification, which allows, when combined with its nanoscale dimension and structural rigidity, this TTA-UC system to acquire various useful functionalities. A benchmark TTA-UC pair, palladium(II) tetraphenyltetrabenzoporphyrin as a sensitizer and perylene as an acceptor, was used to demonstrate efficient red-to-blue (635 nm, 1.95 eV → 470 nm, 2.6 eV) upconversion in the oxygen-rich aqueous phase. The nanocapsule surface was further functionalized with cadmium sulfide nanoparticles (Eg = 2.4 eV) to demonstrate sub-bandgap sensitization and subsequent aqueous-phase catalytic oxidation.

Improved high-pressure enzymatic biodiesel batch synthesis in near-critical carbon dioxide.

The enzymatic synthesis of biodiesel by a high-pressure semi-continuous process in near-critical carbon dioxide (NcCO(2)) was studied. Biodiesel synthesis was evaluated in both batch and semi-continuous systems to develop an effective process. Batch processing demonstrated the advantageous properties of NcCO(2) as an alternative reaction medium. Three immobilized lipases (Novozym 435, Lipozyme RM IM, and Lipozyme TL IM from Novozymes) were tested, with Lipozyme TL IM the most effective, showing the highest conversion. Biodiesel conversion from several edible and non-edible oil feedstocks reached >92%. Higher conversion (99.0%) was obtained in a shorter time by employing repeated batch processes with optimized conditions: 44.3 g (500 mM) canola oil, a substrate molar ratio (methanol:oil) of 3:1, an enzyme loading of 20 wt% (of the oil used), at 30 °C, 100 bar, and 300 rpm agitation. The enzyme maintained 80.2% of its initial stability after being reused eight times. These results suggest that this method produces biodiesel energy-efficiently and environment-friendly.

Catch and release microwave mediated synthesis of cyanine dyes.

Unsymmetrical functionalised cyanine dyes, covering the whole colour range, were readily synthesised (in 100 mg amounts) by a combination of microwave and solid-phase methodologies.

Entangled palladium nanoparticles in resin plugs.

Palladium nanoparticles were entrapped within resin plugs and used in a range of ligand-free cross-coupling reactions; the convenient modular format of the resin plug enhanced resin handling and allowed the catalysts to be easily recovered and multiply reused.

Development of self-indicating resin.

Previously, we have reported the development and application of self-indicating resins (SIR), materials which can indicate presence or absence of amines in the reaction solution by the conspicuous color change of a phenolsulfophthalein type dye immobilized on resin beads [2a]. Although the functionality necessary for attaching the dye to the resins could be readily introduced by the Suzuki-Miyaura coupling during the synthesis of the SIR 1, this approach was only applicable to the dyes containing suitable functionality for the cross-coupling reaction. In this article we describe a new approach of immobilizing the indicating dyes onto the resin support. The dyes suitable for loading onto aminomethyl polystyrene (PS) resin were prepared by Friedel-Crafts reaction of 2-sulfoterephthalic anhydride with a wide range of phenols. Using this new route, the SIR 6c was readily prepared in >100g quantities. Use of the SIR 6c in the synthesis of a 144 member urea library was demonstrated and the SIR successfully indicated the endpoint of the reaction between amines and isocyanates.

Captured and cross-linked palladium nanoparticles.

Polystyrene-poly(ethylene glycol) resin-captured cross-linked palladium nanopaticles were prepared via a straightforward route, and their heterogeneous behavior was truly confirmed by various tests. They were applied to aqueous Suzuki cross-coupling reactions with various aryl bromides and recycled up to six times without loss of activity.

Solid-phase staudinger ligation from a novel core-shell-type resin: a tool for facile condensation of small peptide fragments.

[reaction: see text] Solid-phase Staudinger ligation of small peptides was performed on a novel core-shell-type resin. Solid-phase Staudinger ligation was mediated by synthetic solid-supported phosphinothiol, which was readily prepared by a straightforward synthetic route. This protocol afforded final peptide products in excellent yields and purities and thus could provide the opportunity to facilitate a simple manipulation for condensation of peptide fragments. In particular, the resulting resin could be recycled in a successful manner.

Core-shell-type resins for solid-phase peptide synthesis: comparison with gel-type resins in solid-phase photolytic cleavage reaction.

[reaction: see text] Novel core-shell-type resins with a rigid core and amino-functionalized flexible shell were prepared with 2,4,6-trichloro-1,3,5-triazine (CNC) and Jeffamine ED-600 starting from 1% cross-linked aminomethyl (AM) polystyrene resins. All of the amino groups were located outside the resin beads, and the loading capacity was 0.2-0.4 mmol/g. The amount of CNC treated was a determining factor in the properties of the final resins. The core-shell-type resins showed superior performances in terms of the initial loading of amino acid and the photocleavage reaction compared to the gel-type resins.

pH indicating resins.

pH indicating resins were prepared by covalently attaching carboxylic acid derivatives of sulfthalein dyes, synthesized using a Suzuki cross-coupling, onto resin beads. The resin-bound indicators showed the expected colour changes according to pH and their behaviour was analysed using a micro UV/Vis spectrometer.

Solid-phase synthesis of kojic acid-tripeptides and their tyrosinase inhibitory activity, storage stability, and toxicity.

A small library of kojic acid-tripeptides (Ko-X1X2X3) was prepared by solid-phase parallel synthesis and assayed to evaluate their tyrosinase inhibitory activity. Most of the kojic acid-tripeptides showed better activities than kojic acid. Kojic acid-FWY was the best compound, and it exhibited 100-fold tyrosinase inhibitory activity compared with kojic acid. In addition, their storage stabilities were approximately 15 times higher and their toxicity was lower than that of kojic acid.

Self-indicating amine scavenger resins.

Self-indicating methylisocyanate resin, which functions as both a scavenger and an indicator for amines, was used for in-situ reaction monitoring and purification of a urea based library.