醚-酯型季铵盐阳离子表面活性剂的合成及性能

以硬脂醇、金属钠及3-氯-2-羟基丙基三甲基氯化铵为原料合成了3-烷氧基-2-羟基丙基三甲基氯化铵(OPAC),进一步与硬脂酰氯反应后得到醚-酯型双长链季铵盐阳离子表面活性剂3-烷氧基-2-酰氧基丙基三甲基氯化铵。正交实验确定的最佳合成条件为:1,4-二氧六环为溶剂,用量40mL,n(OPAC)∶n(硬脂酰氯)∶n(吡啶)=1∶1∶1,回流加热反应5h,收率为93.0%。产物结构通过红外及核磁共振氢谱表征。产物表面活性较高,具备良好的织物柔软性及酸碱稳定性。     

煤基活性炭及活性炭纤维对甲烷吸附性研究

Inlfuence of ammonium salt treatment and alkali treatment of the coal based activated carbon （AC） and activated carbon ifber （ACF） adsorbents on methane adsorption capacity was studied via high-pressure adsorption experiment. Sur-face functional groups and pore structure of two types of adsorbents were characterized by the application of infrared ab-sorption spectroscopy （IR） and low temperature liquid nitrogen adsorption method. The results show that both ammonium salt treatment and alkali treatment have obvious effect on changing BET, pore volume as well as pore size distribution of adsorbents; and methane adsorption capacity of the activated carbon ifber is the maximum after the ammonium salt treatment.     

Preliminary Research on Desulfurization of Simulated Diesel Fuel with Peroxotungstate Biquaternary Ammonium Salt/H2O2 System

Abstract

A biquaternary ammonium salt catalyst, chloride-1,4-dibenzyl-diaza-bi-cyclo [2.2.2] octane peroxotungstate (peroxotungstate biquaternary ammonium salt), was prepared, the structure of which was determined through infrared spectrometry, and was applied in desulfurization of simulated diesel fuel. Under the circumstances in which the close ion-pair of biquaternary ammonium cation and peroxotungstate anion was formed, the mechanism of phase transfer catalysis was offered with analyzing experimental process and data. The desulfurization efficiency reached 99.35% when the reaction temperature was 60°C, the reaction time was 20 min, and the molar ratio of peroxotungstate biquaternary ammonium salt to H₂O₂ was 0.015.     

Facile preparation of Cr2O3 nanoparticles and their use as an active catalyst on the thermal decomposition of ammonium perchlorate

ABSTRACT

Cr₂O₃ nanoparticles were prepared by repeated wet mechanical milling technique. Three drying methods, oven drying, vacuum drying, and vacuum freeze-drying were comparatively used to dry Cr₂O₃ nanoparticles. These processes can be easily scaled up to 10-kg quantities. It took only 2–3 h to cut bulk size to nanometer by milling. The obtained Cr₂O₃ nanoparticles are semi-spherical and homogeneous with an average size of 30 nm measured by SEM and TEM and show similar diffraction peak positions to bulk one investigated by XRD. The TG/DSC study indicated that, compared with bulk Cr₂O₃, Cr₂O₃ nanoparticles obtained by oven drying and vacuum drying, the catalytic performance of Cr₂O₃ nanoparticles obtained by vacuum freeze-drying is the best in lowering the peak temperature of high temperature decomposition and the activation energy, while increasing the apparent decomposition heat and the reaction rate constant of ammonium perchlorate (AP) due to their good dispersion and large specific surface area. The possible catalytic mechanism of Cr₂O₃ on the thermal decomposition of AP was proposed by TG-MS analysis. These findings showed that wet mechanical milling technique combined with vacuum freeze-drying technology is suitable for efficient preparation of Cr₂O₃ nanoparticles, which could be a promising additive for accelerating the thermal decomposition of AP.     

Combustion Characteristics and Propulsive Performance of Boron/Ammonium Perchlorate Mixtures in Microtubes

A microthruster is used for the operation tracking and posture control of microsatellites. In this work, the combustion characteristics and propulsive performance of a boron/ammonium perchlorate (B/AP) propellant mixture for a microthruster were investigated. Amorphous B and AP were used in different mass ratios to prepare the propellant samples. A laser-ignition solid micropropulsion test system was set up, and a differential scanning calorimeter was used. The solid combustion products of the samples with good performance were collected. Microstructural and component analyses of the combustion products were performed. Various performance parameters, including the combustion temperature, combustion velocity, spectral intensity, ignition delay time, thrust, specific impulse, density specific impulse, and heat flow, changed with the fuel–oxidant ratio. The optimal fuel–oxidant mass ratio of the propellant samples was 40%, with a density specific impulse of 0.474 kg/m²?s and a maximum heat flow of 4.4913 mW/mg. Analysis of the combustion products revealed that the clearance between particles significantly diminished after combustion. During combustion, the AP completely decomposed, and a large amount of H₃BO₃, B₂O₃, and HBO₂ was generated.     

Antibacterial activity of quaternary ammonium salt grafted cotton

Cotton having good antibacterial activity can be obtained without the need for a binding chemical as a cross linker or the need for chemically pre-treated antibacterial agent. The procedure of synthesis consists in grafting an alkali-cellulose fibre by a quaternary ammonium salt: Epoxy propyltrimethylammonium chloride (EPTMAC). The characterization of grafted cotton (EPTMAC-Cotton) has been targeted on the nitrogen and the methyl group in the ammonium graft structure, by using some analytical techniques, such as infrared, NMR spectroscopy, and volumetric measurement. The antibacterial activity of EPTMAC-Cotton has been studied using four kinds of bacterial stains (Escherichia coli 25922, Pseudomonas aeruginosa 27853, Staphylococcus aureus 259223 and Salmonella LT2DT104 typhimirium). An optimization of conditions of culture medium has been carried out for the bacterial strain for which the modified cotton presents the best antibacterial activity. This optimization is achieved while varying the most important parameters influencing the bacterial growth. We have chosen the pH and the sodium chloride concentration as variable parameters, and we have applied an experiment plant, in order to consider all possible combinations of experiments, and therefore, to estimate the effect of each factor, as well as the effect of their interaction. It has been noticed that a quaternary ammonium salt (EPTMAC) is an efficient antibacterial agent, especially against salmonella in alkaline medium slightly concentrated in salt, and its action depends, in some manner, on the whitening procedure of cotton.     

Reverse micellar extraction of bovine serum albumin – A comparison between the effects of gemini surfactant and its corresponding monomeric surfactant

Gemini surfactant displayed distinct advantages over monomeric surfactant in the liquid–liquid reverse micellar extraction process. First, less amount of gemini surfactant than monomeric surfactant was needed for transferring almost complete bovine serum albumin (BSA) into organic phase from aqueous phase. Second, the loading capacity of gemini surfactant reverse micelle phase was much higher than that of the corresponding monomeric surfactant reverse micelle. Third, efficient backward extraction (75–92%) of BSA could be effected in a wide pH range from 4 to 9 with gemini surfactant reverse micelle while a pH of ca. 4.3 is prerequisite to the recovery of BSA from monomeric surfactant reverse micelle. So far, the reports about the effect of surfactant structure on protein extraction have been limited. This study indicates the important role of the spacer of gemini surfactant in protein extraction process and may provide more knowledge on how to optimise surfactant structure.     

超高浓度水性树脂、聚季胺盐混合废水预处理工艺研究

某化工厂在生产过程中排放的含纤维素、聚季胺盐、异丙醇和氯化物的生产混合废水CODCr达20 000 mg/L,氯化物含量>3 000 mg/L,成分复杂,是一种极难处理的超高浓度特种表面活性剂废水。采用二段pH值调节混凝组合→砂滤→双离子树脂柱交换的预处理工艺进行处理,可去除92.6%的有机负荷,效果明显,出水可直接进入后续生化处理工艺。