Isolated, solvent-extracted lignin from candlenut (Aleurites moluccana) biomass was subjected to catalytic depolymerization in methanol with an added pressure of H 2 , using a porous metal oxide catalyst (PMO) derived from a Cu-doped hydrotalcite-like precursor. The Cu-PMO was effective in converting low-molecular weight lignin into simple mixtures of aromatic products in high yield, without char formation. Gel permeation chromatography was used to track changes in molecular weight as a result of the catalytic treatments and product mixtures were characterized by 1 H and 13 C NMR spectroscopy. In the temperature range 140-220 °C, unusual C9 catechols were obtained with high selectivity. Lignin conversion of >90% and recovery of methanol-soluble products in yields of was >70% was seen at 180 °C with optimized catalyst and biomass loadings. At 140 °C, 4-(3-hydroxypropyl)-catechol was the major product and could be isolated in high purity. † Electronic supplementary information (ESI) available: GPC traces and details of the extraction and purification of lignin from candlenut nutshells; spectroscopic details of low-and high-molecular weight lignins; representative powder XRD data for synthesized hydrotalcite-like catalyst precursor; GPC and NMR spectroscopic data for representative product mixtures after catalytic treatment in the supercritical regime. See
Oxidation catalysts called NewTAMLs, macrocyclic complexes with TAML carbonamido-N donors replaced by more nucleophile-resistant binders, sulfonamido-N, for example, [Fe{4-NO 2 C 6 H 3 -1,2-(NCOCMe 2 NSO 2 ) 2 CHMe}] − (5d), deliver record-setting technical performance parameters (TPPs) for functional peroxidase mimicry. NewTAMLs were designed to test the previously discounted hypothesis that nucleophilic decay of carbonamido-N iron chelators is TAML catalyst lifetime-limiting and, for precautionary reasons, to escape fluorine in the best-performing TAML (1c) for catalyzing ultradilute water purification by H 2 O 2 . Replacing two of four TAML carbonamides with less σ-donating sulfonamides in 5 was found to more than compensate for eliminating 1c's F-substituents to increase substrate oxidation rates and, following the discovery and parametrization of an additional decomposition mechanism, to alter catalyst degradation rates protectively. At pH 7 in less than 5 min, the best-performing NewTAML 5d activates H 2 O 2 to eliminate the β-blocker drug and sentinel micropollutant (MP) propranolol to the limit of UPLC detection under very dilute starting conditions that pass through the ultradilute regime (≤2 ppb): [5d] = 100 nM (∼60 ppb), [propranolol] = 53 nM (15.6 ppb), [H 2 O 2 ] = 330 μM (11.2 ppm). This is ca. 10 times faster than 1c/H 2 O 2 under comparable conditions giving an important advance in the real-world potential for time-, concentration-, and cost-sensitive MP water treatments. The separate decomposition mechanism involves carbon acids bridging the two sulfonamides, a discovery that expands design control over operating NewTAML lifetimesthese features we have named "kill switches" are analyzed for impacts on catalytic function, process control, and sustainable design. Mouse uterotrophic assays show no low-dose adverse effects (lodafs) for the prototype NewTAML (5a) or for the process solution from the 5a/H 2 O 2 destruction of the contraceptive pill estrogen, ethinyl estradiol (EE2), a potent MP. The multidisciplinary catalyst design protocol that led to NewTAMLs is presented graphically to highlight how five key sustainability performancestechnical, cost, health, environmental, fairnessare being optimized together for sustainable oxidation catalysis and water treatment. The results validate the "bioinspired" descriptor and the name sustainable ultradilute oxidation catalysis (SUDOC) for this emerging field while highlighting to chemists that dealing with the lodafs and locafs (low-concentration adverse effects) of everyday−everywhere chemicals is essential for sustainability.
Since the surge of microbiome research in the last decade, many studies have provided insight into the causes and consequences of changes in the gut microbiota. Among the multiple factors involved in regulating the microbiome, exogenous factors such as diet and environmental chemicals have been shown to alter the gut microbiome significantly. Although diet substantially contributes to changes in the gut microbiome, environmental chemicals are major contaminants in our food and are often overlooked. Herein, we summarize the current knowledge on major classes of environmental chemicals (bisphenols, phthalates, persistent organic pollutants, heavy metals, and pesticides) and their impact on the gut microbiome, which includes alterations in microbial composition, gene expression, function, and health effects in the host. We then discuss health-related implications of gut microbial changes, which include changes in metabolism, immunity, and neurological function.
The catalytic activity of the N-tailed ("biuret") TAML (tetraamido macrocyclic ligand) activators [Fe{4-XC6 H3 -1,2-(NCOCMe2 NCO)2 NR}Cl](2-) (3; N atoms in boldface are coordinated to the central iron atom; the same nomenclature is used in for compounds 1 and 2 below), [X, R=H, Me (a); NO2 , Me (b); H, Ph (c)] in the oxidative bleaching of Orange II dye by H2 O2 in aqueous solution is mechanistically compared with the previously investigated activator [Fe{4-XC6 H3 -1,2-(NCOCMe2 NCO)2 CMe2 }OH2 ](-) (1) and the more aggressive analogue [Fe(Me2 C{CON(1,2-C6 H3 -4-X)NCO}2 )OH2 ](-) (2). Catalysis by 3 of the reaction between H2 O2 and Orange II (S) occurs according to the rate law found generally for TAML activators (v=kI kII [Fe(III) ][S][H2 O2 ]/(kI [H2 O2 ]+kII [S]) and the rate constants kI and kII at pH 7 both decrease within the series 3 b>3 a>3 c. The pH dependency of kI and kII was investigated for 3 a. As with all TAML activators studied to-date, bell-shaped profiles were found for both rate constants. For kI , the maximal activity was found at pH 10.7 marking it as having similar reactivity to 1 a. For kII , the broad bell pH profile exhibits a maximum at pH about 10.5. The condition kI ≪kII holds across the entire pH range studied. Activator 3 b exhibits pronounced activity in neutral to slightly basic aqueous solutions making it worthy of consideration on a technical performance basis for water treatment. The rate constants ki for suicidal inactivation of the active forms of complexes 3 a-c were calculated using the general formula ln([S0 ]/[S∞ ])=(kII /ki )[Fe(III) ]; here [Fe(III) ], [S0 ], and [S∞ ] are the total catalyst concentration and substrate concentration at time zero and infinity, respectively. The synthesis and X-ray characterization of 3 c are also described.
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