Flotation of kaolinite and diaspore with hexadecyl dimethyl benzyl ammonium chloride

Tertiary amine was synthesized from fatty amine and formaldehyde. And then the synthesized tertiary amine was used to react with benzyl chloride to synthesize hexadecyl dimethyl benzyl ammonium chloride (1627) at ambient pressure. Using the synthesized 1627 as collector,the flotation properties of diaspore and kaolinite were investigated by single mineral and mixed mineral test. The flotation mechanism of diaspore,kaolinite and 1627 was discussed based on FTIR spectra. The results show that the mass ratio of aluminum to silicate achieves 15.02 and the recovery of alumina in concentrate is 43.07% using 1627 as a collector. The 1627 is found to be a more effective and a promising collector for reverse flotation to remove aluminum-silicate minerals from bauxite.

Solvent-free alkylation of dimethyl malonate using benzyl alcohols catalyzed by FeCl_3/SiO_2

Activated methylene compound such as dimethyl malonate reacted readily with benzylic alcohols in the presence of ferric chloride/silica gel mixture （FeCl3/SiO2） under microwave irradiation to produce benzylic derivative of dimethyl malonate in high yields in solvent-free condition. 2009 Mohammad Reza Shushizadeh. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

Liquid-liquid extraction of phosphorus from sulfuric acid solution using benzyl dimethyl amine

This study addresses the liquid-liquid extraction behavior of phosphorus from a sulfuric acid solution using benzyl dimethyl amine(BDMA)in kerosene.The extraction equilibria investigated with varied BDMA concentrations could reveal the formation of 3[BDMA]·[H_(3)PO_(4)]^(-)complex in the organic phase.The thermodynamic properties determined at various temperatures indicated that the process was exothermic with a calculated enthalpy(△H^(Θ))of−24.0 kJ·mol^(−1).The organic-to-aqueous phase(O/A)volume ratio was varied to elucidate the quantitative extraction of phosphorus.The McCabe-Thiele diagram plotted for the extraction isotherm was validated for the requirement of three counter-current stages in the extraction at an O/A volume ratio of 2.0/3.5.The back-extraction of phosphorus from the loaded organic phase was quantitatively achieved by contacting 4.0 mol·L−1 H2SO4 solution in three stages of counter-current contact at an O/A volume ratio of 3/2.This study can be applied to remove phosphorus from the sulfuric acid leach solutions of monazite processing,and many other solutions.

An effective'salt in dimethyl sulfoxide/water'electrolyte enables high-voltage supercapacitor operated at-50℃

Compared with organic electrolytes,aqueous electrolytes exhibit significantly higher ionic conductivity and possess inherent safety features,showcasing unique advantages in supercapacitors.However,challenges remain for low-salt aqueous electrolytes operating at high voltage and low temperature.Herein,we report a low-salt(0.87 m,m means mol kg^(-1))'salt in dimethyl sulfoxide/water'hybrid electrolyte with non-flammability via hybridizing aqueous electrolyte with an organic co-solvent of dimethyl sulfoxide(hydrogen bond acceptor).As a result,the 0.87 m hybrid electrolyte exhibits enhanced electrochemical stability,a freezing temperature below-50℃,and an outstanding ionic conductivity of 0.52mS cm~(-1)at-50℃.Dimethyl sulfoxide can anchor water molecules through intermolecular hydrogen bond interaction,effectively reinforcing the stability of water in the hybrid electrolyte.Furthermore,the interaction between dimethyl sulfoxide and water molecules diminishes the involvement of water in the generation of ordered ice crystals,finally facilitating the low-temperature performance of the hybrid electrolyte.When paired with the 0.87 m'salt in dimethyl sulfoxide/water'hybrid electrolyte,the symmetric supercapacitor presents a 2.0 V high operating voltage at 25℃,and can operate stably at-50℃.Importantly,the suppressed electrochemical reaction of water at-50℃further leads to the symmetric supercapacitor operated at a higher voltage of 2.6 V.This modification strategy opens an effective avenue to develop low-salt electrolytes for high-voltage and low-temperature aqueous supercapacitors.

Two-Photon Absorption and Fluorescence of a Novel Compound Trans-1,3,5-tri-(4-N,N-Dimethylaminobenzylstyryl)-Acetylacetone

Large two-photon absorption cross section of a novel compound trans-1,3,5-tri-(4-N,N-dimethylaminobenzylstyryl)-acetylacetone is measured to beσ_(2)=8.4×10^(-20)cm^(4)/GW orσ'_(2)=1.594×10^(-47)cm^(4)/(photon.s)by using a 1064 nm Nd:YAG laser with 35 ps pulse width based on the intensity-dependent transmissivity measurement.The frequency upconversion fluorescence is observed by two-photon laser pumping.This material is an ideal candidate for optical limiting and upconversion fluorescence.

Kinetics of Reaction of Bromo-epoxy Resin with Oleic Acid catalyzed by Dimethyl benzyl amine

The kinetics of reaction of bromo-epoxy resin with oleic acid in the presence of dimethylbenzylamine catalyst was studied. The reaction is a zero order reaction with respect to oleic acid, first order with respect to epoxy group and 0. 74 order with respect to dimethylbenzylamine. The reaction rate constants at various temperatures and activation energy were determined. The mechanism of this reaction was discussed. Keywords Tetrabromobisphenol-A, Bromo-epoxy resin, Oleic acid kinetics, Reaction mechanism

Application of Dodecyl Dimethyl Benzyl Ammonium Chloride in Bacteriostatic Laundry Detergent

Bacteriostatic laundry detergent was prepared with application of dodecyl dimethyl benzyl ammonium chloride (1227). In accordance with relevant standards applied in Chinese detergent industry, the effect of 1227 on sensory and physiochemical quality indices, detergency and foaming performance of laundry detergent were comprehensively investigated,and antimicrobial performance as well as practical application performance including skin irritation of laundry detergent formulated with 1227 was emphatically examined and compared with that of market product with similar functions. Results indicated that, in formulation without anionic surfactant, all indices of self-prepared bacteriostatic laundry detergent can meet requirements specified in relevant standards. The foaming power of self-prepared bacteriostatic laundry detergent was lower and easier to rinse than bacteriostatic laundry detergent product in market. Using aqueous solution of 1% mass fraction of self-prepared bacteriostatic laundry detergent containing 2%of 1227, the antibacterial rate for 20 min on both Escherichia coli and Staphylococcus aureus separately reached 100%, which was much better than that of the bacteriostatic laundry detergent product from market. The action effectiveness of the self-prepared bacteriostatic laundry detergent can be maintained for a longer time period and shows no obvious irritation effect to human skin.

Synthesis of mordenite by solvent-free method and its application in the dimethyl ether carbonylation reaction

Mordenite with different Si/Al ratios were synthesized by solvent-free method and used for dimethyl ether(DME)carbonylation reaction.The influence of Si/Al ratio in the feedstock on the structure,porosity and acid sites were systematically investigated.The characterization results showed that with the increase of Si/Al ratio in the feedstock,part of silicon species fail to enter the skeleton and the specific surface area and pore volume of the samples decreased.The amount of weak acid and medium strong acid decreased alongside with the increasing Si/Al ratio,and the amount of strong acid slightly increased.The Al atoms preferentially enter the strong acid sites in the 8 member ring(MR)channel during the crystallization process.The high Si/Al ratio sample had more acid sites located in the 8 MR channel,leading to more active sites for carbonylation reaction and higher catalytic performance.Appropriately increasing the Si/Al ratio was beneficial for the improvement of carbonylation reaction activity over the mordenite(MOR)catalyst.

Hepatoprotective effect of Holothuria leucospilota methanolic extract on dimethyl nitrosamine-induced hepatotoxicity in rats

Background:Complementary medicine is an interesting field for extracting bio-active compounds from various plant and animal sources.The hepatoprotective effect of the methanolic extract of a species of sea cucumber called Holothuria leu-cospilota in an animal model of liver cancer caused by dimethyl nitrosamine(DMN)was studied.Methods:Wistar female rats were randomly divided into five groups(n=12):control(intact),positive control(received 1%DMN[10 mg/kg/week,intraperitoneally]for 12 weeks),and three treatment groups(received 50,100,and 200 mg/kg/day H.leu-cospilota extract orally for 12 weeks along with intraperitoneal administration of 1%DMN[10 mg/kg/week]).In all groups,ultrasound was performed on the liver every week to check its density.Blood sampling and liver isolation were performed on three occasions,at 4,8,and 12 weeks,to check liver enzymes and the histopathological condition of the liver tissue(every week,four animals from each group were randomly selected).Results:Liver density changes were evident from the eighth week onward in the positive control group.Histopathological results indicated pathologic changes in the positive control group after 4 weeks.The increase in liver enzymes in the posi-tive control group was significantly different from that in the treatment and control groups.Conclusions:We demonstrated the hepatoprotective effect of H.leucospilota on DMN-induced liver damage in rats using biochemical and histological parameters and ultrasonography.More additional research(in silico or in vitro)is needed to find the exact mechanism and the main biological compound in H.leucospilota.

Tuning the cross-linked structure of basic poly(ionic liquid)to develop an efficient catalyst for the conversion of vinyl carbonate to dimethyl carbonate

Dimethyl carbonate(DMC)is a crucial chemical raw material widely used in organic synthesis,lithiumion battery electrolytes,and various other fields.The current primary industrial process employs a conventional sodium methoxide basic catalyst to produce DMC through the transesterification reaction between vinyl carbonate and methanol.However,the utilization of this catalyst presents several challenges during the process,including equipment corrosion,the generation of solid waste,susceptibility to deactivation,and complexities in separation and recovery.To address these limitations,a series of alkaline poly(ionic liquid)s,i.e.[DVBPIL][PHO],[DVCPIL][PHO],and[TBVPIL][PHO],with different crosslinking degrees and structures,were synthesized through the construction of cross-linked polymeric monomers and functionalization.These poly(ionic liquid)s exhibit cross-linked structures and controllable cationic and anionic characteristics.Research was conducted to investigate the effect of the cross-linking degree and structure on the catalytic performance of transesterification in synthesizing DMC.It was discovered that the appropriate cross-linking degree and structure of the[DVCPIL][PHO]catalyst resulted in a DMC yield of up to 80.6%.Furthermore,this catalyst material exhibited good stability,maintaining its catalytic activity after repeated use five times without significant changes.The results of this study demonstrate the potential for using alkaline poly(ionic liquid)s as a highly efficient and sustainable alternative to traditional catalysts for the transesterification synthesis of DMC.

Tuning the product selectivity of dimethyl oxalate hydrogenation over WO_(x) modified Cu/SiO_(2) catalysts

Product selectivity and reaction pathway are highly dependent on surface structure of heterogeneous catalysts.For vapor-phase hydrogenation of dimethyl oxalate(DMO),"EG route"(DMO→methyl glycolate(MG)ethylene glycol(EG)→ethanol(ET))and"MA route"(DMO→MG→methyl acetate(MA))were proposed over traditional Cu based catalysts and Mo-based or Fe-based catalysts,respectively.Herein,tunable yield of ET(93.7%)and MA(72.1%)were obtained through different reaction routes over WO_(x) modified Cu/SiO_(2) catalysts,and the corresponding reaction route was further proved by kinetic study and in-situ DRIFTS technology.Mechanistic studies demonstrated that H_(2) activation ability,acid density and Cu-WO_(x) interaction on the catalysts were tuned by regulating the surface W density,which resulted in the different reaction pathway and product selectivity.What's more,high yield of MA produced from DMO hydrogenation was firstly reported with the H_(2) pressure as low as 0.5 MPa.

Synthesis, Crystal Structure and Fungicidal Activity of (Z)-3,3-Dimethyl-1-(1H-1,2,4-triazol-1-yl)butan-2-one O-2-Chlorobenzyl Oxime Nitrate

The title compound has been synthesized by the reaction of 3,3-dimethyl-1-（1H-1,2,4-triazol-1-yl）butan-2-one oxime with 2-chlorobenzyl chloride, and then treated with 65～68% HNO3. Its crystal structure was determined by single-crystal X-ray diffraction. The crystal belongs to the monoclinic system, space group P21/c with a = 14.5481（8）, b = 9.3351（5）, c = 13.1911（7） , β = 98.9450（10）°, Z = 4, V = 1769.67（17） 3, Mr = 369.81, Dc = 1.388 g/cm3, S = 1.06, μ = 0.247 mm-1, F（000） = 776, the final R = 0.0352 and wR = 0.0960 for 3069 observed reflections （I 2σ（I））. X-ray crystal structure presents the intramolecular N–H…O hydrogen bond. The packing is nearly parallel without π-π stacking interactions between two adjacent phenyl rings and stabilized by Van der Waals force. The preliminary bioassay shows that the title compound possesses fungicidal activity against Gibberella zeae at the dosage of 25 mg/L.

Preparation and Properties of 1-octadecanol/1,3:2,4-di-(3,4-dimethyl) Benzylidene Sorbitol/Expanded Graphite Form-stable Composite Phase Change Material

A 1-octadecanol（OD）/1,3:2,4-di-（3,4-dimethyl） benzylidene sorbitol（DMDBS）/expander graphite（EG） composite was prepared as a form-stable phase change material（PCM） by vacuum melting method. The results of field emission-scanning electron microscopy（FE-SEM） showed that 1-octadecanol was restricted in the three-dimensional network formed by DMDBS and the honeycomb network formed by EG. X-ray diffraction（XRD） and Fourier transform infrared spectroscopy（FT-IR） results showed that no chemical reaction occurred among the components of composite PCM in the preparation process. The gel-to-sol transition temperature of the composite PCMs containing DMDBS was much higher than the melting point of pure 1-octadecanol. The improvements in preventing leakage and thermal stability limits were mainly attributed to the synergistic effect of the three-dimensional network formed by DMDBS and the honeycomb network formed by EG. Differential scanning calorimeter（DSC） was used to determine the latent heat and phase change temperature of the composite PCMs. During melting and freezing process the latent heat values of the PCM with the composition of 91% OD/3% DMDBS/6% EG were 214.9 and 185.9 kJ·kg-1, respectively. Its degree of supercooling was only 0.1 ℃. Thermal constant analyzer results showed that its thermal conductivity（κ） changed up to roughly 10 times over that of OD/DMDBS matrix.

Deactivation mechanism of CaO in a flow type dimethyl carbonate synthesis process

It is well known that calcium oxide (CaO) has better catalytic efficiency than most heterogeneous catalysts in many transesterification reactions. However, the gradual deactivation problem prevents its large-scale application in industry. In this paper, the deactivation mechanism of CaO in a fixed-bed reactor is investigated based on the transesterification reaction of propylene carbonate and methanol. The leaching amount of CaO during the reaction was estimated by the concentration of Ca in the products. The pretreated and recovered catalysts were characterized by FT-IR, XRD, TG-MS and SEM-EDS. It is evident from experiments and characterization that the deactivation process of CaO is accompanied by the leaching of calcium species and the generation of CaCO3, which are also verified by DFT calculations. At high temperature and high weight hourly space velocity, the deactivation was attributed to the formation of dense CaCO3 shell, which prevents the contact between the feedstock and the active species inside.

Synthesis of Methyl Acetate by Dimethyl Ether Carbonylation over Cu/HMOR： Effect of Catalyst Preparation Method

Dimethyl ether carbonylation to methyl acetate was comparatively investigated over mor- denite supported copper （Cu/HMOR） catalysts prepared by different methods including evaporation, urea hydrolysis, incipient wetness impregnation and ion-exchange. The results showed that Cu/HMOR prepared via iron-exchange method exhibited the highest catalytic activity due to the synergistic effect of active-site metal and acidic molecular sieve support. Conversion of 95.3% and methyl acetate selectivity of 94.9% were achieved under conditions of 210℃, 1.5 MPa, and GSHV of 4883 h-1. The catalysts were characterized by nitrogen absorption, X-ray diffraction, NH3 temperature program desorption, and CO temperature program desorption techniques. It was found that Cu/HMOR prepared by ion-exchange method possessed high surface area, moderate strong acid centers, and CO adsorption centers, which improved catalytic performance for the reaction of CO insertion to dimethyl ether.

Effect of Calcination Temperature on Catalytic Activity and Textual Property of Cu/HMOR Catalysts in Dimethyl Ether Carbonylation Reaction

The effect of calcination temperature on the catalytic activity for the dimethyl ether （DME） carbonylation into methyl acetate （MA） was investigated over mordenite supported copper （Cu/HMOR） prepared by ion-exchange process. The results showed that the catalytic activity was obviously affected by the calcination temperature. The maximal DME conversion of 97.2% and the MA selectivity of 97.9% were obtained over the Cu/HMOR calcined at 430 ℃ under conditions of 210 ℃, 1.5 MPa, and GSHV of 4883 h^-1. The obtained Cu/HMOR catalysts were characterized by powder X-ray diffraction, N2 absorption, NH3 temperature program desorption, CO temperature program desorption, and Raman techniques. Proper calcination temperature was effective to promote copper ions migration and diffusion, and led the support HMOR to possess more acid activity sites, which exhibited the complete decomposing of copper nitrate, large surface area and optimum micropore structure, more amount of CO adsorption site and proper amount of weak acid centers.

SYNTHESIS OF 3,7-DIMETHYL-2-TRIDECANYL ACETATE--Active Component of Sex Pheromone of Pine Sawfly Diprion pini

The total synthesis of 3,7 dimethyl 2 tridecanyl acetate,the active component of the sex pheromone of diprion pini,was investigated in this paper.The two key synthins blocks,2 methyl octan 1 yl lithium and 3,4 dimethyl γ butyrolactone,were obtained from diethyl malonate and 2,3 epoxybutane.2 Methyl octan 1 yl lithium reacted with 3,4 dimethyl γ butyrolactone to yield the ketoalcohol and then followed by Huang Minlong reduction to afford 3,7 dimethyl 2 tridecanol,acylated with acetic anhydide to give 3,7 dimethyl 2 tridecanyl acetate.

Production of Light Olefins from Biosyngas by Two-stage Catalytic Conversion Process via Dimethyl Ether

NiSAPO-34 and NiSAPO-34/HZSM-5 were prepared and evaluated for the performance of dimethyl ether （DME） conversion to light olefins （DTO）. The processes of two-stage light olefin production, DME synthesis and the following DTO, were also investigated using biosyngas as feed gas over Cu/Zn/A1/HZSM-5 and the optimized 2%NiSAPO-34/HZSM- 5. The results indicated that adding 2%Ni to SAPO-34 did not change its topology structure, but resulted in the forming of the moderately strong acidity with decreasing acid amounts, which slightly enhanced DME conversion activity and C2=-C3= selectiw ity. Mechanically mixing 2%NiSAPO-34 with HZSM-5 at the weight ratio of 3.0 further prolonged DME conversion activity to be more than 3 h, which was due to the stable acid sites from HZSM-5. The highest selectivity to light olefins of 90.8% was achieved at 2 h time on stream. The application of the optimized 2%NiSAPO-34/HZSM-5 in the second-stage reactor for DTO reaction showed that the catalytic activity was steady for more than 5 h and light olefin yield was as high as 84.6 g/m3syngas when the biosyngas （H2/CO/CO2/N2/CH4=41.5/26.9/14.2/14.6/2.89, vol%） with low H/C ratio of 1.0 was used as feed gas.

富马酸二甲酯减轻帕金森病模型鼠神经损伤的作用机制

背景:帕金森病是一种特征为多巴胺能神经元进行性丢失的多因素神经系统疾病,富马酸二甲酯(dimethyl fumarate,DMF)在神经退行性疾病中具有强大的神经保护和免疫调节作用。目的:探究DMF对MPTP诱导的帕金森病小鼠模型的神经保护机制。方法:选取24只C57BL/6系小鼠,随机将其分为对照组、模型组及DMF低剂量和DMF高剂量组。除对照组外,其余各组小鼠腹腔注射MPTP 30 mg/kg,1次/d,连续注射5 d,建立帕金森病的动物模型。每次注射MPTP后间隔30 min给予小鼠灌胃,DMF低剂量组和DMF高剂量组每天分别灌胃DMF 30,50 mg/kg,1次/d,对照组和模型组灌同等剂量的生理盐水,连续灌胃7 d。通过行为学检测、Western Blot、氧化应激标志物检测和免疫组织化学染色等方法,分析DMF对MPTP诱导的帕金森病小鼠氧化应激和Keap1/Nrf2信号通路的调节作用,以及DMF对多巴胺神经元变性的保护机制。结果与结论:①与模型组比较,DMF低剂量组小鼠的运动迟缓和姿势平衡障碍得到明显改善(P<0.01),在DMF高剂量组中的改善更为显著(P<0.01)。②与对照组相比,模型组氧化应激标志物丙二醛明显升高,超氧化物歧化酶表达降低(P<0.01);与模型组相比,DMF低、高剂量组降低了丙二醛的产生,增加了超氧化物歧化酶的表达(P<0.01)。③模型组小鼠的中脑黑质多巴胺能神经元数目和酪氨酸羟化酶蛋白表达较对照组明显减少(P<0.01),而DMF低剂量组小鼠的黑质多巴胺能神经元数目和蛋白表达增多(P<0.01),DMF高剂量组改善更明显(P<0.01)。④模型组Keap1蛋白表达升高伴随Nrf2蛋白表达降低;与模型组相比,DMF组降低了Keap1蛋白表达且伴随Nrf2蛋白表达增多(P<0.01)。⑤结果说明,DMF对帕金森病小鼠黑质区Keap1/Nrf2通路有调控作用,且与剂量呈现正相关(P<0.01),推测DMF依赖于Keap1/Nrf2信号发挥神经元保护作用。

Ag-Ni alloy nanoparticles for electrocatalytic reduction of benzyl chloride

Ag-based nanocatalysts exhibit good catalytic activity for the electrochemical reduction of organic halides. Ag-Ni alloy nanoparticles（NPs） were facilely prepared by chemical reduction, and the as-prepared nanocatalysts were characterized by X-ray diffraction, ultraviolet-visible spectroscopy, transmission electron microscopy and energy-dispersive X-ray spectroscopy. The electrocatalytic activity of Ag-Ni NPs for benzyl chloride reduction was studied in organic medium using cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscopy. The results show that the addition of Ni element can obviously decrease the size of Ag-Ni NPs, shift the reduction peak potential（φp） of benzyl chloride positively, and increase the catalytic activity of Ag-Ni NPs. However, when the Ni content reaches a certain value, the catalytic activity of Ag-Ni NPs decreases. Meanwhile, the synergistic catalytic effect of Ag-Ni NPs was also discussed.