Synthesis of Hydrotalcite from Seawater and Its Application to Phosphorus Removal

10.0 wt% milk of lime was added to seawater containing AlCl 3 at Mg/Al molar ratio of 3.0 until pH 10.5 with stirring, and kept at 25;C for 1 h. Hydrotalcite (HT) was precipitated as a single phase, and Mg 2+ and Al 3+ were quantitatively precipitated. The chemical composition was [Mg 0.75 Al 0.25 (OH) 2 ][(SO 4 ) 0.06 (Cl) 0.02 (OH) 0.11 *];0.27H 2 O* (*Balance). A 100 mg-P/L Na 2 HPO 4 solution and the HT were shaken at 25;C. Phosphate removal increased with increasing time and the HT quantity, and was the highest at pH 7-9. Phosphate ion could be quantitatively removed, adding 8 times the stoichiometric quantity of the HT at pH 8.7 for 6 h.     

Specific uptake of aromatic compounds from aqueous solution by montmorillonite modified with tetraphenylphosphonium

Montmorillonite (MT) modified with tetraphenylphosphonium (TPP·MT) had specific uptake behavior for aromatics in aqueous solution. This is attributed to the extent of π–π stacking interactions between the benzene rings of intercalated TPP⁺ and the benzene rings of aromatics with different electronic states. The uptake order of aromatics by TPP·MT was in contrast to that by layered double hydroxide (LDH) intercalated with 2,7-naphthalene disulfonate. The selective uptake of target aromatic compounds from aqueous solution can be achieved by combining appropriate inorganic layered compounds and modified aromatic ions.     

Powerful Ti-crossed Claisen condensation between ketene silyl acetals or thioacetals and acid chlorides or acids

[Structure: see text] A powerful Ti-crossed Claisen condensation between ketene silyl acetals (KSAs) and acid chlorides was successfully performed to give alpha-monoalkylated esters and thermodynamically unfavorable (less accessible) alpha,alpha-dialkylated beta-keto esters in good yield (46 examples; 41-98% yield). A closely related reaction between ketene silyl thioacetals (KSTAs) and acid chlorides also proceeded smoothly to give alpha-monoalkylated and alpha,alpha-dialkylated beta-keto thioesters (21 examples; 61-97% yield). The present protocol was extended to the direct condensation of KSAs with carboxylic acids (14 examples; 71-97% yield).     

A Structurally Robust Chiral Borate Ion: Molecular Design,Synthesis, and Asymmetric Catalysis

Catalysis by chiral weakly-coordinating anions (WCAs) remains underdeveloped due to the lack of a molecular design strategy for exploiting their characteristics, such as the non-nucleophilic nature. Here, we report the development of a chiral borate ion comprising an O,N,N,O-tetradentate backbone, which ensures hitherto unattainable structural robustness. Upon pairing with a proton, the hydrogen borate acts as an effective catalyst for the asymmetric Prins-type cyclization of vinyl ethers, providing access to structurally and stereochemically defined dihydropyrans. The key to selectivity control is the distinct ability of the borate ion to discriminate the prochiral faces of the acyclic oxonium ion intermediate and dictate the regiochemical outcome. We anticipate that this study paves the way for exploring the untapped potential of WCA catalysis for selective chemical synthesis.     

Relation between annoyance and single-number quantities for rating heavy-weight floor impact sound insulation in wooden houses

This study investigated the relation between annoyance and single-number quantities to rate heavy-weight floor impact sound insulation. Laboratory experiments were conducted to evaluate the subjective response of annoyance resulting from heavy-weight floor impact sounds recorded in wooden houses. Stimuli had two typical spectra and their modified versions, which simulate the precise change in frequency response resulting from insulation treatments. Results of the first experiment showed that the Zwicker's percentile loudness (N(5)) was the quantity to rate most well annoyance of heavy-weight impact sound over a wide sound level range. The second experiment revealed that arithmetic average (L(iFavg,Fmax)) of octave-band sound pressure levels measured using the time constant "fast" and Zwicker's percentile loudness (N(5)) much better described annoyance by the precise change in the sound spectrum attributable to insulation treatments than Japanese standardized single-number quantities (L(i,Fmax,r), L(iA,Fmax), and L(i,Fmax,Aw)) do. Japanese standardized single-number quantities using the A-weighting curve as a rating curve were found to be excessively influenced by the 63 Hz octave-band sound level and have the great sound level-dependences in the relation with subjective ratings.     

Practical and robust method for regio- and stereoselective preparation of (E)-ketene tert-butyl TMS acetals and beta-ketoester-derived tert-butyl (1Z,3E)-1,3-bis(TMS)dienol ethers

We developed an efficient, practical, robust method for the regio- and stereoselective preparation of (E)-ketene trimethylsilyl acetals (KSAs) derived from tert-butyl esters 1. The reaction was performed under convenient reaction conditions; LDA-TMSCl, 0-5 degrees C, and cyclopentyl methyl ether (CPME) solvent. Two kinds of (Z)- and (E)-KSAs derived from alpha-oxygen and alpha-nitrogen-substituted tert-butyl esters, respectively, were also obtained in good yield. The present protocol was successfully applied to a stereocontrolled preparation of useful, but highly reactive (less accessible) beta-ketoester-derived tert-butyl (1Z,3E)-1,3-bis(TMS)dienol ethers 2.     

Syntheses,Structures, and Reactivities of Two Chalcogen‐Stabilized Carbones

Electronic effects on the central carbon atom of carbone, generated by the replacement of the S^IV ligand of carbodisulfane (CDS) with other chalcogen ligands (Ph₂E, E=S or Se), were investigated. The carbones Ph₂E→C←SPh₂(NMe) [E=S( 1 ) or Se( 2 )] were synthesized from the corresponding salts, and their molecular structures and electronic properties were characterized. The carbone 2 is the first carbone containing selenium as the coordinated atom. DFT calculations revealed the electronic structures of 1 and 2 , which have two lone pairs of electrons at the carbon center. The trend in HOMO energy levels, estimated by cyclic voltammetry measurements, for the carbones and CDS follows the order of 2 > 1 >CDS. Analysis of a doubly protonated dication and trication complex revealed that the central carbon atom of 2 behaves as a four‐electron donor.     

Recovery of indium from In2O3 and liquid crystal display powder via a chloride volatilization process using polyvinyl chloride

Indium (In) was recovered from indium oxide (In₂O₃) and liquid crystal display (LCD) powder via a chloride volatilization process using polyvinyl chloride (PVC) as the chlorination agent. The recovery of In from In₂O₃ increased with an increasing molar Cl/In ratio in N₂ and air atmospheres. The degree of In recovery at a Cl/In molar ratio of 11 and a temperature of 350 °C was 98.7% and 96.6%, for N₂ and air, respectively. The In recovery also increased notably with increasing temperature in N₂ atmosphere. In both atmospheres, the In recovery increased with an increasing degradation temperature of PVC. However, the In recovery from LCD powder was lower than that from In₂O₃. For LCD powder, the degree of In recovery at a Cl/In molar ratio of 11 and a temperature of 350 °C was 66.7% and 54.1%, for N₂ and air, respectively.     

Carbon–carbon bond formation via benzoyl umpolung attained by photoinduced electron-transfer with benzimidazolines

A photoreaction between benzoyl compounds, such as benzoylformate derivatives, and 2-(p-anisyl)-1,3-dimethylbenzimidazoline in the presence of allyl bromide was found to give various allylated alcohols. In the reaction of benzoylformates, α-hydroxy ester enolates, for which the negative charge occurs on the carbonyl carbon of benzoyl (umpolung reactivity), are proposed to be generated as intermediates by electron-transfer from benzimidazolines to the photoexcited benzoylformates; these species react with allyl bromide to produce α-allyl-α-hydroxy esters.