scholarly journals Conversion of Cellulose Into 5-Hydroxymethylfurfural (HMF) In a H2O/Tetrahydrofuran/Cyclohexane Biphasic System With Al2(SO4)3 As Catalyst

2021 ◽  
Author(s):  
Ning Shi ◽  
Yuju Zhu ◽  
Bangzhi Qin ◽  
Ying Liu ◽  
Hongyan Zhang ◽  
...  
Keyword(s):  
Liquid Film ◽  
Aqueous Phase ◽  
Organic Phase ◽  
Reaction Temperature ◽  
High Efficiency ◽  
Reaction System ◽  
Biphasic System ◽  
High Yield ◽  
High Concentration ◽  
The Stability

Abstract A simple and efficient biphasic system consisting of H2O, tetrahydrofuran (THF), cyclohexane (CHX) and Al2(SO4)3 was employed to convert cellulose into 5-hydroxymethylfurfural (HMF) with high yield of 71.2%. The real volumes of organic phase (Vorg) and aqueous phase (Vaque) of the biphasic system at reaction temperature were measured to found out that over 80% of the added H2O was dissolved into the organic phase at reaction temperature, leading to high Vorg/Vaque (over 44/1) and high concentration of Al2(SO4)3 (over 0.34 g/mL) in aqueous phase. The high concentration of Al2(SO4)3 in aqueous phase could efficiently catalyze the conversion of cellulose into HMF, while the high Vorg/Vaque could protect the formed HMF from rehydration, all of which are responsible for the high efficiency of the system on conversion of cellulose into HMF. The addition of CHX into reaction mixture could decrease the solubility of Al2(SO4)3 and H2O in the organic phase, which could improve the stability of HMF in the reaction system, resulting higher yield of HMF from cellulose. Because of the high Vorg/Vaque of the reaction system, one microemulsion-like system and liquid film catalytic model are proposed for the cellulose-to-HMF process.

scholarly journals Near quantitative synthesis of urea macrocycles enabled by bulky N-substituent

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yingfeng Yang ◽  
Hanze Ying ◽  
Zhixia Li ◽  
Jiang Wang ◽  
Yingying Chen ◽  
...  
Keyword(s):  
High Efficiency ◽  
Molecular Structures ◽  
High Yield ◽  
Kinetic Control ◽  
High Concentration ◽  
Weak Association ◽  
Quantitative Synthesis ◽  
Thermodynamic Stabilization ◽  
Discrete Structures ◽  
Very High

AbstractMacrocycles are unique molecular structures extensively used in the design of catalysts, therapeutics and supramolecular assemblies. Among all reactions reported to date, systems that can produce macrocycles in high yield under high reaction concentrations are rare. Here we report the use of dynamic hindered urea bond (HUB) for the construction of urea macrocycles with very high efficiency. Mixing of equal molar diisocyanate and hindered diamine leads to formation of macrocycles with discrete structures in nearly quantitative yields under high concentration of reactants. The bulky N-tert-butyl plays key roles to facilitate the formation of macrocycles, providing not only the kinetic control due to the formation of the cyclization-promoting cis C = O/tert-butyl conformation, but also possibly the thermodynamic stabilization of macrocycles with weak association interactions. The bulky N-tert-butyl can be readily removed by acid to eliminate the dynamicity of HUB and stabilize the macrocycle structures.

Study of Gas Production by Anaerobic Fermentation and Microbial Community Changes by In-Situ Microaerobic Desulphurization

2020 ◽  
Vol 14 (4) ◽  
pp. 517-523
Author(s):  
Yan Zhou ◽  
Hucheng Liu ◽  
Wei Kou ◽  
Lijie Shao ◽  
Peihan Liu ◽  
...  
Keyword(s):  
High Throughput Sequencing ◽  
High Efficiency ◽  
Anaerobic Fermentation ◽  
Low Cost ◽  
Total Solid ◽  
Common Species ◽  
Gas Production ◽  
High Concentration ◽  
Fermentation System ◽  
The Stability

The enhancement of biogas quality at low cost and high efficiency process was one of the purposes of biogas engineering. In this work, we designed a reactor for microaerobic desulphurization. We used this reactor to study the anaerobic fermentation in systems that used cow manure with total solid (TS) concentrations of 18.5%, 15% and 10%. The influence of anaerobic fermentation on the stability of gas production and the characteristics of the gas produced with different concentrations of fermentation materials was studied. The strain structure of the fermentation system was obtained by high-throughput sequencing and taxonomy was compared. The H2S removal results showed that the average rates of the H2S removal in concentrations of fermentation materials of 18.5%, 15%, and 10% TS were 99.2%, 97.8%, and 78.8%, respectively. 16SrRNA sequencing was performed in different fermented samples as well as a comparison between samples in order to determine the number of unique species (NUS) and the number of common species (NCS). By comparing TS 18.5 with TS 15 and TS 10 samples, it was determined that under fermentation conditions, NUS were 113 and 106, respectively. Whereas NUS were 31 and 41, respectively, when comparing TS 15 and TS 10. These demonstrated that the number of strain species in the fermentation system with TS 18.5% was far more than those found in the systems with low concentration of fermentation. Also, the ability for disturbance resistance of the microaerobic desulphurization system was stronger at high concentration of the fermentation.

scholarly journals Ni(II) immobilization by bio-apatite materials: Appraisal of chemical, thermal and combined treatments

2016 ◽  
Vol 22 (1) ◽  
pp. 117-126 ◽  
Author(s):  
Marija Sljivic-Ivanovic ◽  
Aleksandra Milenkovic ◽  
Mihajlo Jovic ◽  
Slavko Dimovic ◽  
Ana Mrakovic ◽  
...  
Keyword(s):  
Organic Phase ◽  
High Efficiency ◽  
Calcium Hydroxyapatite ◽  
Organic Content ◽  
Sorption Data ◽  
Animal Bones ◽  
Maximum Sorption ◽  
Sequential Extraction Analysis ◽  
Contamination Levels ◽  
The Stability

Animal bones are natural and rich source of calcium hydroxyapatite (HAP), which was found to be a good sorbent material for heavy metals and radionuclides. Various treatments can reduce the content of bone organic phase and improve sorption properties. In this study, sorption capacities of raw bovine bones (B) and samples obtained by chemical treatment with NaOH (BNaOH), by heating at 400 oC (B400) and by combined chemical and thermal treatment (BNaOH+400), were compared, using Ni(II) ions as sorbates. Maximum sorption capacities increased in the order B<BNaOH<B400<BNaOH+400. Based on different sorption data and FT-IR analyses, the mechanism of Ni(II) sorption was found to be complex, with participation of both HAP and organic phase (when present). Sequential extraction analysis was applied for testing the stability of Ni(II) ions sorbed by BNaOH+400. Majority of Ni(II) was found in residual phase (65%) at lower level of sorbent loading, while with the increase of sorbent saturation carbonate fraction became dominant (39 %). According to the results, BNaOH+400 can be utilized in water purification systems. As an apatite based material with low organic content and high efficiency for Ni(II) sorption, it is also a good candidate for in-situ soil remediation, particularly at lower contamination levels.

Extraction of promethium complex with 4-benzoyl-5-methyl-2-phenyl-2,4-dihydro-3H-pyrazol-3-one into Freon 113 and its mixtures with benzene

1991 ◽  
Vol 56 (10) ◽  
pp. 2096-2099
Author(s):  
Petr Linhart
Keyword(s):  
Stability Constant ◽  
Aqueous Phase ◽  
Organic Phase ◽  
Extraction Constant ◽  
The Stability

A study of the dependence of distribution of Pm(III) between aqueous phase ( perchlorate medium) and Freon 113 (or a Freon 113-benzene mixture 2 : 1) on pH and pA has shown that the complex PmA3 is extracted into the organic phase with the extraction constant log Kex = -4.35. The stability constant βn of the complex PmA3 has been calculated by the Leden method.

Extraction of some metals into solutions of 1-phenyl-3-methyl-4-benzoylpyrazolone-5 in freon 113

1980 ◽  
Vol 45 (4) ◽  
pp. 1221-1226 ◽  
Author(s):  
Oldřich Navrátil ◽  
Pavel Linhart
Keyword(s):  
Ionic Strength ◽  
Aqueous Solutions ◽  
Stability Constants ◽  
Aqueous Phase ◽  
Organic Phase ◽  
Extraction Constants ◽  
Distribution Constants ◽  
The Stability

The partition of 1-phenyl-3-methyl-4-benzoylpyrazolone-5 (HA) between aqueous solutions of HClO4 and NaClO4, ionic strength 0.1, and Freon 113 or its 2 : 1 mixture with benzene was studied. The logarithms of the HA distribution constants are 2.84 ± 0.10 and 3.39 ± 0.15 for the two organic phases, respectively. The extraction curves of cerium(III) and europium(III) revealed that in dependence on the pH of the aqueous phase, the metals are transferred into the organic phase in the form of the MA3 complexes (M = Ce, Eu). The stability constants of the complexes MAn in the aqueous phase were determined along with their distribution and extraction constants. For cobalt, zinc, and hafnium, a part of the extraction curves could only be studied, only the extraction constants were therefore determined. The sparing solubility of HA in Freon 113 can be circumvented by using a Freon-benzene mixture 2 : 1, which is still practically incombustible.

scholarly journals Understanding the aqueous phase ozonolysis of isoprene: distinct product distribution and mechanism from the gas phase reaction

2012 ◽  
Vol 12 (15) ◽  
pp. 7187-7198 ◽  
Author(s):  
H. L. Wang ◽  
D. Huang ◽  
X. Zhang ◽  
Y. Zhao ◽  
Z. M. Chen
Keyword(s):  
Organic Acids ◽  
Gas Phase ◽  
Aqueous Phase ◽  
Reaction System ◽  
Chemical Processes ◽  
Total Carbon ◽  
High Yield ◽  
Phase Reaction ◽  
Gas Phase Reaction ◽  
Wet Particles

Abstract. The aqueous phase reaction of volatile organic compounds (VOCs) has not been considered in most analyses of atmospheric chemical processes. However, some experimental evidence has shown that, compared to the corresponding gas phase reaction, the aqueous chemical processes of VOCs in the bulk solutions and surfaces of ambient wet particles (cloud, fog, and wet aerosols) may potentially contribute to the products and formation of secondary organic aerosol (SOA). In the present study, we performed a laboratory experiment of the aqueous ozonolysis of isoprene at different pHs (3–7) and temperatures (4–25 °C). We detected three important kinds of products, including carbonyl compounds, peroxide compounds, and organic acids. Our results showed that the molar yields of these products were nearly independent of the investigated pHs and temperatures, those were (1) carbonyls: 56.7 ± 3.7 % formaldehyde, 42.8 ± 2.5 % methacrolein (MAC), and 57.7 ± 3.4 % methyl vinyl ketone (MVK); (2) peroxides: 53.4 ± 4.1 % hydrogen peroxide (H2O2) and 15.1 ± 3.1 % hydroxylmethyl hydroperoxide (HMHP); and (3) organic acids: undetectable (<1 % estimated by the detection limit). Based on the amounts of products formed and the isoprene consumed, the total carbon yield was estimated to be 94.8 ± 4.1 %. This implied that most of the products in the reaction system were detected. The combined yields of both MAC + MVK and H2O2 + HMHP in the aqueous isoprene ozonolysis were much higher than those observed in the corresponding gas phase reaction. We suggest that these unexpected high yields of carbonyls and peroxides are related to the greater capability of condensed water, compared to water vapor, to stabilize energy-rich Criegee radicals. This aqueous ozonolysis of isoprene (and possibly other biogenic VOCs) could potentially occur on the surfaces of ambient wet particles and plants. Moreover, the high-yield carbonyl and peroxide products might provide a considerable source of aqueous phase oxidants and SOA precursors.

Calix[4]arene-crown-5 as a selective extraction reagents for K+/H+, Rb+/H+ and Rb+/Cs+ separations

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Petr Vaňura ◽  
Emanuel Makrlík ◽  
Pavel Selucký
Keyword(s):  
Stability Constants ◽  
Aqueous Phase ◽  
Organic Phase ◽  
Selective Extraction ◽  
Nitrobenzene Solution ◽  
Two Phase ◽  
Extraction Constants ◽  
Exchange Extraction ◽  
Phase Water ◽  
The Stability

Abstract From extraction experiments, the exchange extraction constants corresponding to the general equilibriums M+ (aq) + NaL+ (org) ⇔ ML+ (org) + Na+ (aq) or M+ (aq) + CsL+ (org) ⇔ ML+ (org) + Cs+ (aq), which take place in the two-phase water–nitrobenzene extraction system (M+ = Li+, H3O+, Ag+, K+, NH4 +, Tl+, Rb+; L = calix[4]arene-bis crown5(1,3-alternate), 26,28-dipropoxycalix[4]arene-crown-5(1,3-alternate), 11,23-dibromo-25,28-dipropoxycalix[4]arene-crown-5 (1,3-alternate) and 1,3-alternate-25,27-dihydroxycalix[4]arene-crown-5; aq = aqueous phase, org = organic phase), were evaluated. The stability constants of the NaL+ and CsL+ complexes were calculated from the extraction of the respective picrates in the system of water–nitrobenzene solution of L. Further, the stability constants of the ML+ complexes in nitrobenzene saturated with water were determined. High selectivities were found in some systems under study.

Study of Anchor Bolt Support in Deep Hard Roof of Roadway of Tangshan Mine

2014 ◽  
Vol 945-949 ◽  
pp. 1163-1168 ◽  
Author(s):  
Rui Xi Zhang ◽  
Yu Kai Lv ◽  
Cong Jiang
Keyword(s):  
High Efficiency ◽  
Simulation Method ◽  
Surrounding Rock ◽  
High Yield ◽  
Anchor Bolt ◽  
Hard Roof ◽  
Mining Depth ◽  
Working Face ◽  
The Stability ◽  
Bolt Support

Traditional trellis support was mainly used in deep mining roadway of Kailuan group. With the increase of mining depth, section of roadway and deformation of surrounding rock also increased gradually. As a passive support ways of roadway, trellis support had been unable to meet the requirements of high yield and high efficiency comprehensive mechanized mining. Therefore, anchor bolt supportis in urgent need to turn passive support into active support and to ensure the safety and the stability of surrounding rock of roadway, meanwhile, the cost saving and boosting yield was made sure. This paper is based on the physical and mechanical parameters of coal seam roof and floor of working face 1357w, numerical simulation method was took, and the parameters of anchor bolt support suitable for the roadway with working face were also studied. The result of study could provide theoretical basis for later projects.

High yield production of 5-hydroxymethylfurfural from cellulose by high concentration of sulfates in biphasic system

2013 ◽  
Vol 15 (7) ◽  
pp. 1967 ◽  
Author(s):  
Ning Shi ◽  
Qiying Liu ◽  
Qi Zhang ◽  
Tiejun Wang ◽  
Longlong Ma
Keyword(s):  
Biphasic System ◽  
High Yield ◽  
High Concentration ◽  
Yield Production ◽  
High Yield Production

REMOVAL OF HEAVY METAL Cr (II), Ni (II), Cu (II), Zn (II), Cd (II), Pb (II) IONS FROM AQUEOUS SOLUTION BY MENTHA PIPERITA EXTRACT

2020 ◽  
pp. 15-20
Author(s):  
Ersin Yucel ◽  
Mine Yucel
Keyword(s):  
Aqueous Solution ◽  
Metal Ions ◽  
High Efficiency ◽  
Correlation Coefficients ◽  
Langmuir Model ◽  
Mentha Piperita ◽  
Freundlich Model ◽  
Biosorption Capacity ◽  
Peppermint Extract ◽  
The Stability

In this study, the usage of the peppermint (Mentha piperita) for extracting the metal ions [Mg (II), Cr (II), Ni (II), Cu (II), Zn (II), Cd (II), Pb (II)] that exist at water was investigated. In order to analyze the stability properties, Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherms were used at removing the metal ions and the highest correlation coefficients (R2) were obtained at Langmuir isotherm. Therefore, it is seen that the Langmuir model is more proper than the Freundlich model. However, it was found that the correlation coefficients of removing Ni and Cd is higher at Freundlich model than Langmuir and low at Dubinin-Radushkevich isotherm. It is established that the biosorption amount increase depends on the increase of biosorbent and it can be achieved high efficiency (95%) even with small amount (0.6 mg, peppermint extract) at lead ions. It is also determined that the peppermint extracted that is used at this study shows high biosorption capacity for metal ions and can be used for immobilization of metals from polluted areas.

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