106989-11-1Relevant academic research and scientific papers
Degradation of tri(2-chloroisopropyl) phosphate by the UV/H2O2 system: Kinetics, mechanisms and toxicity evaluation
He, Huan,Ji, Qiuyi,Gao, Zhanqi,Yang, Shaogui,Sun, Cheng,Li, Shiyin,Zhang, Limin
, (2019)
A photodegradation technology based on the combination of ultraviolet radiation with H2O2 (UV/H2O2) for degrading tri(chloroisopropyl) phosphate (TCPP) was developed. In ultrapure water, a pseudo-first order reaction was observed, and the degradation rate constant reached 0.0035 min?1 (R2 = 0.9871) for 5 mg L?1 TCPP using 250 W UV light irradiation with 50 mg L?1 H2O2. In detail, the yield rates of Cl? and PO43? reached 0.19 mg L?1 and 0.58 mg L?1, respectively. The total organic carbon (TOC) removal rate was 43.02%. The pH value of the TCPP solution after the reaction was 3.46. The mass spectrometric detection data showed a partial transformation of TCPP into a series of hydroxylated and dechlorinated products. Based on the luminescent bacteria experimental data, the toxicity of TCPP products increased obviously as the reaction proceeded. In conclusion, degradation of high concentration TCPP in UV/H2O2 systems may result in more toxic substances, but its potential application for real wastewater is promising in the future after appropriate optimization, domestication and evaluation.
Facile synthesis of CeO2-supported gold nanoparticle catalysts for selective oxidation of glycerol into lactic acid
Lakshmanan, Pandian,Upare, Pravin P.,Le, Ngoc-Thuc,Hwang, Young Kyu,Hwang, Dong Won,Lee, U-Hwang,Kim, Hyung Rok,Chang, Jong-San
, p. 260 - 268 (2013)
This study explores a new synthetic route toward CeO2-supported gold nanoparticles catalysts (1, 3, and 5 wt.% Au) and their catalysis of the oxidation of glycerol at atmospheric pressure. Gold was loaded on a hydrothermally synthesized nanocrystalline CeO2 support (～8 nm) via deposition-precipitation with urea (DPU). To obtain cerium oxide-supported gold nanoparticles, thermal reduction at 300 C under flowing H2 is currently popular. However, this method invariably forms small gold particles (2 catalysts prepared by DPU were reduced via a new method: chemical reduction with glycerol (CRG). Interestingly, the reduction of a gold-urea complex supported on ceria occurs at 25 C, and the gold nanoparticles grow slowly. The resultant chemically reduced samples were compared with their hydrogen-reduced counterparts. The CRG method primarily generated gold particles with larger average sizes than the H2 reduction method. Importantly, the CRG route enabled variation of the average gold nanoparticle size without requiring any other reagent, which is particularly advantageous for the Au/CeO2 system. The efficiency of these catalysts toward the aerobic oxidation of glycerol was tested. Accordingly, the selective oxidation of glycerol into lactate can be effectively catalyzed by Au/CeO2 catalysts at atmospheric pressure. The chemically reduced samples show increased lactate selectivity than the hydrogen-reduced samples due to the larger size of the gold particles.
Lattice distortion induced electronic coupling results in exceptional enhancement in the activity of bimetallic PtMn nanocatalysts
Jin, Xin,Zeng, Chun,Yan, Wenjuan,Zhao, Meng,Bobba, Pallavi,Shi, Honghong,Thapa, Prem S.,Subramaniam, Bala,Chaudhari, Raghunath V.
, p. 46 - 57 (2017)
Lattice strain plays a critical role in structural heterogeneity and surface electronic properties of bimetallic nanocatalysts. However, understanding of how to engineer optimal electron transfer in anisotropic bimetallic crystals remains a grand challenge to achieve enhanced catalytic performances. We investigate beyond conventional polymer based core-shell and alloy structures, and present unique lattice distorted PtMn catalysts fabricated via a cooperative self-assembly method. The strong internal strain between Pt and Mn lattices is found to induce the structural distortion of anisotropic PtMn crystals and formation of asymmetric flower shapes, leading to stretched Pt and contracted Mn lattices. Such distorted bimetallic crystals exhibit unusual electronic coupling and an eight-fold synergistic enhancement in catalytic oxidation of renewable biomass feedstocks compared with monometallic Pt catalysts. The novel synthesis technique and revealed electronic coupling mechanism described herein opens the door for the rational discovery of other bimetallic nanocatalysts with positive synergy.
Lactic acid production from aqueous-phase selective oxidation of hydroxyacetone
Albuquerque, Elise M.,Borges, Luiz E.P.,Fraga, Marco A.
, p. 64 - 70 (2015)
Lactic acid is an important chemical with a wide range of application in food, pharmaceutical and chemical industries. Its worldwide demand has increased due to the ever-growing market of poly(lactic acid) - PLA. This present contribution aims at studying the catalytic transformation of hydroxyacetone toward lactic acid over heterogeneous systems. Commercial Pt/Al2O3 powder catalysts were used and their main features were analyzed as concerning their chemical composition (XRF), crystalline structure (XRD), morphology (TEM) and porosity (N2 physisorption). Catalytic performance was evaluated in aqueous phase and the results showed that the catalytic activity and selectivity to lactic acid depends on the pH of the reaction medium, being mandatory to operate under strong alkaline conditions. Such reaction conditions promote both the initial oxidation of hydroxyacetone and the intramolecular disproportionation of the obtained aldehyde, which are fundamental steps to lactic acid formation. More importantly, this contribution reports the feasibility of alternatively using heterogeneous catalysts to produce lactic acid with high selectivity (>96%).q
Synergetic effect of Lewis acid and base in modified Sn-β on the direct conversion of levoglucosan to lactic acid
Chi, Zixin,Hu, Wenda,Lin, Jingdong,Wan, Shaolong,Wan, Yan,Wang, Shuai,Wang, Yong
, p. 2986 - 2993 (2020)
This work presents a novel method to selectively convert levoglucosan to lactic acid (LA) via initially adding LA as the Br?nsted acid together with modified Sn-β as the Lewis acid. Sn-β catalysts exchanged with various cations significantly enhance the yield of LA, following the order Sn-β 2+ and Mg2+ appears to be more effective in promoting the retro-aldol condensation due to the synergetic effect of their stronger Lewis acid that can stabilize the oxygen atom of deprotonated alkoxides during the reaction. The LA yield from levoglucosan can reach up to 66% on Sn-β-Ca under the optimized conditions. We also demonstrated that such a synergetic effect of alkaline-earth ion exchanged Sn-β shows great universality toward enhanced retro-aldol condensation, which can significantly promote the yield of methyl lactate over glucose conversion in methanol solvent.
SIMULTANEOUSLY OCCURRING HYDROXYLATION, HYDRATION, AND HYDROGENATION OF THE C=C BOND OF ALIPHATIC CARBOXYLIC ACIDS IN AQUEOUS SOLUTION BY GLOW DISCHARGE ELECTROLYSIS
Kokufuta, Etsuo,Shibasaki, Takami,Sodeyama, Touro,Harada, Kaoru
, p. 1569 - 1572 (1985)
Glow discharge electrolysis of maleic and acrylic acids in carbonate-free distilled water simultaneously afford the products into which OH and/or H groups are introduced, indicating the addition reactions of OH and H radicals to the C=C bond.
Efficient conversion of pyruvic aldehyde into lactic acid by lewis acid catalyst in water
Koito, Yusuke,Nakajima, Kiyotaka,Kitano, Masaaki,Hara, Michikazu
, p. 873 - 875 (2013)
Homogeneous and heterogeneous catalysts with watertolerant Lewis acids, such as Sc(OTf)3 and Nb2O5·nH2O effectively promote the hydride transfer of pyruvic aldehyde into lactic acid in water at 383 K, whereas Bronsted acid catalysts cannot function as effective catalysts under mild conditions. NMR measurement in the presence of D2O suggests that the reaction on a Lewis acid catalyst proceeds via the MeerweinPonndorfVerley (MPV) reduction.
Preparation of Sn-Β-zeolite via immobilization of Sn/choline chloride complex for glucose-fructose isomerization reaction
Bayu, Asep,Karnjanakom, Surachai,Kusakabe, Katsuki,Abudula, Abuliti,Guan, Guoqing
, p. 426 - 433 (2017)
Well dispersion of tin species in an isolated form is a quite challenge since tin salts are easily hydrolyzed into (hydr)oxides during aqueous stannation of β-zeolite. In this study, immobilization of tin species on high silica commercial β-zeolite by using SnCl2/Choline chloride (ChCl) complex followed with calcination provided a convenient way to get well dispersed Sn in β-zeolite in the aqueous condition, which was observed based on electron microscopy images, UV visible spectra and X-ray diffraction pattern. The existence of ChCl facilitated tin species to incorporate into zeolite. (1?2) wt% of Sn loaded β-zeolites exhibited good catalytic activity and high selectivity for glucose-fructose isomerization reaction.
Lanthanum oxycarbonate modified Cu/Al2O3 catalysts for selective hydrogenolysis of glucose to propylene glycol: Base site requirements
Yazdani,Wang,Du,Kawi,Borgna
, p. 4680 - 4690 (2017)
This work reports on the base properties of La2O2CO3-Cu/Al2O3 catalysts and their effect on the catalyst's performance in the aqueous hydrogenolysis of glucose to propylene glycol. The catalysts show promising performance in glucose isomerisation, C-C bond cleavage of fructose and hydrogenation of the resulting fragments. The base properties of the catalyst influence the selectivity. More specifically, the basicity of the catalyst facilitates the isomerisation of glucose to fructose and the C-C bond cleavage of fructose to produce lighter products. This is evidenced by the correlation between the acid-base properties of the catalysts and their catalytic performance. In contrast, acid sites promote side reactions such as condensation reactions. Based on this study, a surface reaction mechanism is proposed for the first step of the tandem reactions, the isomerisation of glucose to fructose. The effect of the reaction time and temperature on the product distribution was investigated to get more insight into the reaction pathways. In this regard, the conversion of intermediates was also investigated. Then, a reaction mechanism was proposed based on the findings of this study and previous works.
Highly active and recyclable Sn-MWW zeolite catalyst for sugar conversion to methyl lactate and lactic acid
Guo, Qiang,Fan, Fengtao,Pidko, Evgeny A.,Van Der Graaff, William N. P.,Feng, Zhaochi,Li, Can,Hensen, Emiel J. M.
, p. 1352 - 1356 (2013)
Not just sugar! Lewis-acidic Sn-MWW zeolites are obtained through postsynthesis functionalization of deboronated B-MWW with Sn. These materials are highly active, selective, and recyclable catalysts for the conversion of triose sugars to methyl lactate (in methanol) and lactic acid (in water). They also demonstrate good performance in the conversion of hexose sugars and sucrose to methyl lactate. Copyright
