高效液相色谱法同时测定液体酸化剂中的有机酸含量

试验旨在使用高效液相色谱法同时测定液体酸化剂中甲酸、乙酸、丙酸、丁酸的含量。经过色谱条件优化比较,确立了最佳色谱条件为:采用Atlantis T3柱(250 mm×4.6 mm,5μm)作为色谱柱,柱温30℃,流动相使用乙腈和20 mmol/L的KH_(2)PO_(4)缓冲盐溶液(pH值2.9)进行梯度洗脱,流速为1 mL/min,紫外检测波长220 nm,进样量20μL。结果显示,4种有机酸分离良好,线性范围广,相关系数为0.999 7~1.000 0,检出限为0.26~0.53 mg/L,定量限为0.70~2.65 mg/L,加标回收率在94.1%~101.2%之间,相对标准偏差(RSD)均小于1.93%。研究表明,高效液相色谱法高效快捷、定量准确,适用于液体酸化剂中有机酸的检测。

液体酸化剂的评估及其对肉鸡生长性能的影响

试验旨在研究不同比例液体酸化剂对饮用水的酸化作用、水质硬度的软化效果、饮水中大肠杆菌的抑菌效果及酸化水对肉鸡生产性能的影响。结果显示:液体酸化剂能够能显著降低水的pH值(P<0.05);硬水中添加0.2%液体酸化剂能显著降低水的硬度(P<0.05);0.2%液体酸化剂能显著抑制大肠杆菌生长(P<0.05)。以饮用0.2%液体酸化剂酸化后的饮用水的肉鸡作为试验组,饮用未经酸化的饮用水为对照组,结果显示:与对照组相比,试验组肉鸡21、42 d体重显著增加(P<0.05);22~42、0~42 d平均日增重显著增加(P<0.05);22~42 d平均日采食量显著增加(P<0.05);1~21、22~42、1~42 d料重比显著降低(P<0.05);1~21、22~42、1~42 d腹泻发生率显著降低(P<0.05);试验组肉鸡群粪便干爽、成型度好。研究表明,液体酸化剂能很好地酸化水质、降低水的硬度、抑制大肠杆菌的繁殖,酸化水可以提高肉鸡的生长性能。

液体酸化剂富酸宝对水质及母猪繁殖性能的影响

为了探究液体酸化剂富酸宝对水质以及母猪繁殖性能的影响,实验选取体况相近,2~4胎长大二元杂母猪36头,随机分成2组,每组18头。在妊娠107天时,在试验组母猪饮用水中添加0.05%液体酸化剂-“富酸宝”调节饮用水的pH值为3.6,而对照组饮用普通水,试验持续32d。结果表明:当“富酸宝”与水的比例由1:100~1:10000时,水的pH值为2.5~4.0;对照组与试验组水塔中水的微生物含量分别为51个和49个相对光单位(约相当于800cfu/mL),水塔水质达到畜禽饮用水水质要求,而对照组哺乳母猪栏舍内水中微生物含量达到1000个相对光单位(相当于30000cfu/mL),污染相当严重;与对照组相比,试验组中哺乳母猪栏舍内水中微生物含量仅为3个相对光单位(约相当于20cfu/mL),水中99.7%微生物被杀灭。与对照组相比,试验组仔猪25日龄断奶均重、断奶活仔数、仔猪平均日增重与仔猪成活率分别提高了11.96%、7.49%、 15.49%、 4.41%;此外,与对照组相比,试验组仔猪腹泻率为0,腹泻率下降了100%。与对照组相比,试验组哺乳母猪平均采食量、断奶时母猪背膘厚与母猪断奶7d再发情率分别提高了32.43%、 7.34%、 10.08%;与对照组相比,试验组母猪背膘损失下降、背膘损失率分别下降了27.52%与26.45%。可见,“富酸宝”可以有效降低饮水pH值,降低饮水中微生物总数,刺激母猪采食,缩短母猪发情间隔,提高仔猪断奶重,并降低仔猪腹泻率。

Epoxidation of Unsaturated Fatty Acid Methyl Esters in the Presence of SO_3H-functional Brφnsted Acidic Ionic Liquid as Catalyst

The epoxidation of unsaturated fatty acid methyl esters(FAMEs)by peroxyacetic acid generated in situ from hydrogen peroxide and acetic acid was studied in the presence of SO3H-functional Brnsted acidic ionic liquid (IL)[C3SO3HMIM][HSO4]as catalyst.The effects of hydrogen peroxide/ethylenic unsaturation ratio,acetic acid concentration,IL concentration,recycling of the IL catalyst,and temperature on the conversion to oxirane were studied.The kinetics and thermodynamics of unsaturated FAMEs epoxidation and the kinetics of oxirane cleavage of the epoxidized FAMEs by acetic acid were also studied.The conversion of ethylenic unsaturation group to oxirane, the reaction rate of the conversion to oxirane,and the rate of hydrolysis(oxirane cleavage)were higher by using the IL catalyst.

Synthesis of isosorbide-based polycarbonates via melt polycondensation catalyzed by quaternary ammonium ionic liquids

A series of quaternary ammonium ionic liquids(ILs)were synthesized and employed as catalysts for the production of poly(isosorbide carbonate)(PIC)from diphenyl carbonate and isosorbide via a melt polycondensation process.The relationship between the anions of the ILs and the catalytic activities was investigated,and the readily‐prepared IL tetraethylammonium imidazolate(TEAI)was found to exhibit the highest catalytic activity.After optimizing the reaction conditions,a PIC with a weight‐average molecular weight(Mw)of25600g/mol was obtained,in conjunction with an isosorbide conversion of92%.As a means of modifying the molecular flexibility and thermal properties of the PIC,poly(aliphatic diol‐co‐isosorbide carbonate)s(PAIC)s were successfully synthesized,again using TEAI,and polymers with Mw values ranging from29000to112000g/mol were obtained.13C NMR analyses determined that the PAIC specimens had random microstructures,while differential scanning calorimetry demonstrated that each of the PAICs were amorphous and had glass transition temperatures ranging from50to115°C.Thermogravimetric analyses found Td‐5%values ranging from316to332°C for these polymers.Based on these data,it is evident that the incorporation of linear or cyclohexane‐based diol repeating units changed the thermal properties of the PIC.

Novel efficient procedure for biodiesel synthesis from waste oils with high acid value using 1-sulfobutyl-3-methylimidazolium hydrosulfate ionic liquid as the catalyst

Preparation of biodiesel from waste oils containing 72% of free fatty acids catalyzed by a novel Br?nsted acidic ionic liquid 1-sulfobutyl-3-methylimidazolium hydrosulfate([BHSO_3MIM][HSO_4]) was systematically investigated.The optimum molar ratio of methanol to waste oils,catalyst amount,reaction temperature and reaction time were 8/1,10%(based on the mass of waste oils),140°C and 6 h,respectively,under which the obtained yield of biodiesel reached 94.9%.Also,[BHSO_3MIM][HSO_4] as a catalyst still retained around 97% of its original catalytic activity after successive re-use of 5 batches(6 h per batch),showing the excellent operational stability.Moreover,the acidic IL [BHSO_3MIM][HSO_4] was able to ef ficiently catalyze conversions of waste oils with different amounts of FFAs(free fatty acids) into biodiesel,and showed tremendous application potential.Therefore,an ef ficient and environmentally friendly catalyst is provided for the synthesis of biodiesel from waste oils with high acid value.

Research progress in ionic liquids catalyzed isobutane/butene alkylation

The complicated reaction mechanism and the character of competitive reactions lead to a stringent requirement for the catalyst of C_4 alkylation process. Due to their unique properties, ionic liquids(ILs) are thought to be new potential acid catalysts for C_4 alkylation. An analysis of the regular and modified chloroaluminate ILs, novel Br?nsted ILs and composite ILs used in isobutane/butene alkylation shows that the use of either ILs or ILs coupled with mineral acid as homogeneous catalysts can help to greatly adjust the acid strength. By modifying the structural parameters of the cations and anions of the ILs, the solubility of the reactants could also be adjusted, which in turn displays a positive effect on improving the activity of ILs. Immobilization of ILs is an effective way to modulate the surface adsorption/desorption properties and acid strength distribution of the solid acid catalysts. Such a process has a tremendous potential to reduce the deactivation of catalyst and enhance the activity of the solid acid catalyst. The development of novel acid catalysts for C_4 alkylation is a comprehensive consideration of acid strength and its distribution, interfacial properties and transport characteristics.

Honeycomb-structured solid acid catalysts fabricated via the swelling-induced self-assembly of acidic poly(ionic liquid)s for highly efficient hydrolysis reactions

The development of heterogeneous acid catalysts with higher activity than homogeneous acid catalysts is critical and still challenging.In this study,acidic poly(ionic liquid)s with swelling ability(SAPILs)were designed and synthesized via the free radical copolymerization of ionic liquid monomers,sodium p-styrenesulfonate,and crosslinkers,followed by acidification.The 31P nuclear magnetic resonance chemical shifts of adsorbed trimethylphosphine oxide indicated that the synthesized SAPILs presented moderate and single acid strength.The thermogravimetric analysis results in the temperature range of 300–345°C revealed that the synthesized SAPILs were more stable than the commercial resin Amberlite IR-120(H)(245°C).Cryogenic scanning electron microscopy testing demonstrated that SAPILs presented unique three-dimensional(3D)honeycomb structure in water,which was ascribed to the swelling-induced self-assembly of the molecules.Moreover,we used SAPILs with micron-sized honeycomb structure in water as catalysts for the hydrolysis of cyclohexyl acetate to cyclohexanol,and determined that their catalytic activity was much higher than that of homogeneous acid catalysts.The equilibrium concentrations of all reaction components inside and outside the synthesized SAPILs were quantitatively analyzed using a series of simulated reaction mixtures.Depending on the reaction mixture,the concentration of cyclohexyl acetate inside SAPIL-1 was 7.5–23.3 times higher than that outside of it,which suggested the high enrichment ability of SAPILs for cyclohexyl acetate.The excellent catalytic performance of SAPILs was attributed to their 3D honeycomb structure in water and high enrichment ability for cyclohexyl acetate,which opened up new avenues for designing highly efficient heterogeneous acid catalysts that could eventually replace conventional homogeneous acid catalysts.

Removal of Trace Olefins from Aromatics Catalyzed by[bmim]Br-AlCl_3 Ionic Liquid

1-Butyl-3-methylimidazolium bromochloroaluminate （[bmim]Br-AlCl3） ionic liquid was used as an acid catalyst for removal of trace olefins from the aromatic hydrocarbons. The influence of various reaction parameters such as reaction time, temperature, dosage and acid strength of catalyst was investigated. The experimental results demonstrated that the ionic liquid exhibited excellent activity under mild reaction conditions, with the conversion of olefins reaching 98.84% and the bromine index of the aromatics varying from 1129 to 13. On the basis of the results obtained, thereof, a possible reaction mechanism was proposed.

N-methyl-2-pyrrolidonium-based Br?nsted-Lewis acidic ionic liquids as catalysts for the hydrolysis of cellulose

We experimentally studied the catalytic performances of a series of Brrnsted-Lewis acidic N-methyl-2-pyrrolidonium metal chlorides （[Hnmp]Cl/MClx, where M=Fe, Zn, A1, or Cu） for the hydrolysis of microcrystalline cellulose （MCC） and cotton to produce reducing sugar. A variety of factors, such as temperature, time, ionic liquid （IL） species, IL dosage, and the concentra- tion of the metal chloride were investigated. [Hnmp]Cl/FeCl3 presented the best hydrolysis performance, affording a 98.8% yield of total reducing sugar from MCC （1 h, 100 ℃, 0.1 g MCC, 0.2 g acidic IL, 2.0 g [Bmim]Cl as solvent）, which is better than or comparable to results previously obtained with other -SO3H functionalized acidic ILs. The hydrolysis performances of [Hnmp]Cl/MClx were rationalized using density functional theory calculations, which indicated that interactions between the metal chlorides and the cellulose, including charge-transfer interactions are important in the hydrolysis of cellulose and degra- dation of glucose. This work shows that Bronsted-Lewis acidic ILs are potential catalysts for the hydrolysis of cellulose to produce sugar.

Extraction mechanism of rare earths from chloride acidic solution with ammonium-bifunctionalized ionic liquid extractants

A series of ammonium-bifunctionalized ionic liquid extractants （ammonium-Bif-ILEs） combined with a number of anions, in- cluding carboxylic acids and 1,3-diketonates, have been prepared and studied in this report. Their extraction behavior and properties toward rare earth ions （REs（III）） are systematically investigated in chloride media as a function of important param- eters such as aqueous phase pH, salting-out agent concentrations, and extraction temperature. The separation performance of ammonium-Bif-ILEs toward REs（III） are systematically discussed. The results demonstrate that ammonium-Bif-ILEs have a synergistic effect between the cation and anions in separation of REs（III）. The influences of different anions on separation fac- tor （β） values are further studied. By comparison, ammonium-Bif-ILEs containing 1,3-diketonates have more potential appli- cations in La（III）/RE（III） separation than those containing carboxylic acids.