Catalytic Oxidative Cleavage of C(OH)-C Bonds in Lignin Model Compounds to Carboxylic Acids by Fe(NO3)3.9H2O/NaI/DMSO.

The secondary C(OH)-C bonds are abundant in biomass such as lignin and cellulose. Thus, selective cleavage of the C(OH)-C bonds into value chemicals attracted much attention. Molecular iodine has received considerable attention as an inexpensive and readily available catalyst to yield the corresponding products in excellent yields with high selectivity, but it is highly corrosive and toxic, making its use somewhat unattractive. In this study, I2 was generated in situ from Fe(NO3)3.9H2O/NaI, which was further combined with Fe(NO3)3.9H2O to catalyze the oxidation process. In the reaction, the H2O molecule from the reaction and Fe(NO3)3.9H2O attacked the phenylglyoxal to form benzaldehyde, which was further oxidized to benzoic acid. Aryl primary and secondary benzylic alcohols from lignin were successfully transformed into aryl carboxylic acids by Fe(NO3)3.9H2O/NaI/DMSO. The catalytic system was green and efficient, avoiding the usage of toxic and corrosive molecular I2. From the experiments, it was clear that the yield of the product from the substrates with an electron-donating group was higher than that of electron-withdrawing substituted substrates, which was similar to the aryl secondary alcohols. Aryl alkyl ketones were also successfully conducted by the Fe(NO3)3.9H2O/NaI/DMSO catalytic system.

Enhancing As(V) and As(III) adsorption performance of low alumina fly ash with ferric citrate modification: Role of FeSiO3 and monosodium citrate.

Fly ash and arsenic species have been regarded as contaminants that pollute the environment. Herein, low alumina fly ash (LAFA) was utilized to fabricate the As(V) and As(III) adsorbent via combining the routes of alkali fusion and incipient-wetness impregnation. The characterization results suggested that the grafted ferric citrate was coordinated to LAFA by substituting a Si4+ to a Fe3+, and the compound monosodium citrate was observed. Based on the XPS analysis, the C-O and -COO- groups of monosodium citrate played the significant role in uptaking As(V) and As(III) species by chemical complexation, the FeOOH adsorbed As(V) and As(III) species via ion-exchange, and the Fe2O3 oxidize As(III) into As(V). Additionally, it was observed that the As(V) removal performance by adsorbent prepared with different modifiers was in the order of FeC6H5O7 (ca. 93.7%) > C6H8O7 (84%) > HCl (73%). And then, the optimal adsorbent synthesis condition for As(V) uptake was explored at ferric citrate loaded LAFA with 1:1 mass ratio (fly ash to NaOH) under temperature 923 K. The maximum monolayer adsorption capacities of the optimal adsorbent were 2725.0 µgAs(V)/g and 2281.9 µgAs(III)/g, and the removal efficiency of As(V) and As(III) was near 100% for their initial concentrations below 500 ppb, where the residual arsenic concentration met the required standard in drinking water (lower than 10 ppb).

An epidermal equivalent assay for identification and ranking potency of contact sensitizers.

The purpose of this study was to explore the possibility of combining the epidermal equivalent (EE) potency assay with the assay which assesses release of interleukin-18 (IL-18) to provide a single test for identification and classification of skin sensitizing chemicals, including chemicals of low water solubility or stability. A protocol was developed using different 3D-epidermal models including in house VUMC model, epiCS® (previously EST1000™), MatTek EpiDerm™ and SkinEthic™ RHE and also the impact of different vehicles (acetone:olive oil 4:1, 1% DMSO, ethanol, water) was investigated. Following topical exposure for 24h to 17 contact allergens and 13 non-sensitizers a robust increase in IL-18 release was observed only after exposure to contact allergens. A putative prediction model is proposed from data obtained from two laboratories yielding 95% accuracy. Correlating the in vitro EE sensitizer potency data, which assesses the chemical concentration which results in 50% cytotoxicity (EE-EC50) with human and animal data showed a superior correlation with human DSA05 (µg/cm(2)) data (Spearman r=0.8500; P value (two-tailed)=0.0061) compared to LLNA data (Spearman r=0.5968; P value (two-tailed)=0.0542). DSA05=induction dose per skin area that produces a positive response in 5% of the tested population Also a good correlation was observed for release of IL-18 (SI-2) into culture supernatants with human DSA05 data (Spearman r=0.8333; P value (two-tailed)=0.0154). This easily transferable human in vitro assay appears to be very promising, but additional testing of a larger chemical set with the different EE models is required to fully evaluate the utility of this assay and to establish a definitive prediction model.