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991.
Yeast biomass was methylated in a 0.1 M HCl methyl alcohol solution at room temperature and the methylated yeast (MeYE) was applied to the adsorptive separation of Cr(VI) and As(V) anions from aqueous solutions. At near-neutral pH, while Cr(VI) and As(V) anions were scarcely adsorbed onto unmethylated yeast biomass, the amounts adsorbed increased with increasing methylation degree. The amount of Cr(VI) adsorbed onto MeYE was almost constant at pH 4-6 and decreased with increasing pH above pH 6. The amount of As(V) adsorbed onto MeYE was rather lower than that of Cr(VI) and it had a peak at about pH 7. A metal-binding model was used to describe the adsorption characteristics of Cr(VI) and As(V) on MeYE. The results showed that MeYE has two different types of adsorption sites. The saturated amount of Cr(VI) and As(V) adsorbed onto MeYE having methylation degree 0.94 was 0.55 mmol g(-1). 相似文献
992.
993.
Yuki Nagao Yuzuru Imai Jun Matsui Tomoyuki Ogawa Tokuji Miyashita 《The Journal of chemical thermodynamics》2011,43(4):613-616
We synthesized seven partially protonated poly(aspartic acids)/sodium polyaspartates (P-Asp) with different average molecular weights to study their proton transport properties. The number-average degree of polymerization (DP) for each P-Asp was 30 (P-Asp30), 115 (P-Asp115), 140 (P-Asp140), 160 (P-Asp160), 185 (P-Asp185), 205 (P-Asp205), and 250 (P-Asp250). The proton conductivity depended on the number-average DP. The maximum and minimum proton conductivities under a relative humidity of 70% and 298 K were 1.7 · 10?3 S cm?1 (P-Asp140) and 4.6 · 10?4 S cm?1 (P-Asp250), respectively. Differential thermogravimetric analysis (TG-DTA) was carried out for each P-Asp. The results were classified into two categories. One exhibited two endothermic peaks between t = (270 and 300) °C, the other exhibited only one peak. The P-Asp group with two endothermic peaks exhibited high proton conductivity. The high proton conductivity is related to the stability of the polymer. The number-average molecular weight also contributed to the stability of the polymer. 相似文献
994.
Simultaneous Delamination and Rutile Formation on the Surface of Ti3C2Tx MXene for Copper Adsorption
In this work, we studied the formation of the rutile phase of titanium dioxide (TiO2) on delaminated MXene (d‐Ti3C2Tx) flakes by the reaction of Ti3C2Tx with amino acids in water. Three types of amino acids with varied side‐chain polarity were used to delaminate Ti3C2Tx. d‐Ti3C2Tx flakes formed stable colloidal solutions due to the negative surface charges of chemisorbed amino acids on the d‐Ti3C2Tx. Rutile formed on d‐Ti3C2Tx at room temperature upon the intercalation of aromatic amino acids and subsequent sonication of the solution, while flakes intercalated with aliphatic amino acids did not oxidize. X‐Ray diffraction (XRD), transmission electron microscopy (TEM) and Raman spectroscopy revealed the nanosize rutile formation on the surface of Ti3C2Tx flakes. The XPS results indicated the surface functionalization of histidine on d‐Ti3C2Tx flakes. As‐synthesized histidine functionalized rutile TiO2@d‐Ti3C2Tx hybrid was used for adsorption of Cu2+ ions from aqueous solution with a maximum uptake of 95 mg g?1. 相似文献
995.
Abstract The epoxidation of allylic alcohols with H2O2 catalyzed by a new Mo-species, [PMo12O40]3?[C5H5N+(CH2)15CH3]3 (MPCP), prepared from 12-molybdatophosphoric acid (H3PMo12O40) and cetylpyridinium chloride [C5H5N+(CH2)15CH3 · Cl?], has recently rep0rted.) The high regioselectivity for the epoxidation by this MPCP-H2O2 system was comparable to that of Sharpless method using t-BuOOH as oxidant. 相似文献
996.
Iida A Okazaki H Misaki T Sunagawa M Sasaki A Tanabe Y 《The Journal of organic chemistry》2006,71(14):5380-5383
TiCl4-Lewis base (AcOEt, CH3NO2) complexes smoothly deprotected tert-butyldimethylsilyl (TBDMS) ethers. The reaction velocity with these complexes, which seemed less reactive due to the influence of Lewis bases, was considerably greater than that with TiCl4 alone. Selective desilylations between aliphatic and aromatic TBDMS ethers (1 and 5), between 1 and benzyl, allyl, tosyl, methoxyphenyl, and chloroacetyl ethers (13, 14, 15, 16, and 17), and between TBDMS and TBDPS ethers (18 and 19) were successfully performed. Desilylation of TBDMS-aldol, acyloin, and beta-lactam analogues 9-12 proceeded smoothly due to anchimeric assistance by the neighboring carbonyl groups. The present method was successfully applied to the practical synthesis of 1beta-methylcarbapenems 20a'-f'. 相似文献
997.
Dr. Aya Yoshimura Yuki Takamachi Prof. Dr. Li‐Biao Han Prof. Dr. Akiya Ogawa 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(40):13930-13933
An efficient metal‐free diboration of terminal alkynes is reported. In the presence of a catalytic amount of organosulfides under light, the addition of bis(pinacolato)diboron (B2pin2) to terminal alkynes takes place efficiently to produce the corresponding double borylation products in good yields. Mechanistic studies indicate that this metal‐free sulfide‐catalyzed diboration of alkynes likely occurs by generation of a boryl‐centered radical with the aid of light and a sulfide, since such a radical was detected in the reaction mixture by electron spin resonance (ESR) spectroscopy. The present form of catalysis (sulfide/light) is thought to be unprecedented and provides a new means of preparation for organoboranes without heavy metal contamination in the products, which is highly desired in the preparation of drugs and electronic materials. 相似文献
998.
999.
T. Ishii M. Asai A. Makishima I. Hossain P. Kleinheinz M. Ogawa M. Matsuda S. Ichikawa 《The European Physical Journal A - Hadrons and Nuclei》2002,13(1-2):15-19
Nuclei in the neutron-rich Ni region have been studied by γ-ray spectroscopy. Gamma-rays emitted from isomers, with T
1/2 > 1 ns, produced in heavy-ion deep-inelastic collisions were measured with an isomer-scope. The nuclear structure of the
doubly magic 68Ni and its neighbor 69,71Cu is discussed on the basis of the shell model. Future experiments for more neutron-rich Ni nuclei are also viewed.
Received: 1 May 2001 / Accepted: 4 December 2001 相似文献
1000.