Sensitivity of green and blue-green algae to methyl tert-butyl ether

The toxicity of methyl tert-butyl ether （MTBE） to Chlorella ellipsoidea and Aphanizomenon flos-aquae was tested and assessed for a 15-d incubation with concentrations of MTBE from high （2.00×10^4 mg/L） to low （2 mg/L）. The results showed that the toxicity was low when the concentration of MTBE was in the range 1.00× 10^4-2.00× 10^4 mg/L （the greatest inhibition of growth-rate was 70%-71%, occurred during the day 1-5）. Low concentrations （2-500 rag/L） stimulated algal growth up to the greatest effect of 85%-200% when the concentration of MTBE was 50-100 mg/L during day 3-5. The toxicity of MTBE （72-120 h EC50） was 6.65×10^3-9.58×10^3 mg/L for C. ellipsoidea and that is 1.14× 10^4-2.00× 10^4 mg/L for A. floc-aquae. We found that the toxicity and ecological risk of MTBE for the algal community structure were low and the toxicity was influenced by the duration time of the test.

Aerobic degradation of methyl tert-butyl ether by a Proteobacteria strain in a closed culture system

The contamination of methyl ten-butyl ether （MTBE） in underground waters has become a widely concerned problem all over the world. In this study, a novel dosed culture system with oxygen supplied by H2O2 was introduced for MTBE aerobic biodegradation. After 7 d, almost all MTBE was degraded by a pure culture, a member of β-Proteobacteria named as PMI, in a closed system with oxygen supply, while only 40% MTBE was degraded in one without oxygen supply. Dissolved oxygen （DO） levels of the broth in closed systems respectively with and without H2O2 were about 5-6 and 4 mg/L. Higher DO may improve the activity of monooxygemase, which is the key enzyme of metabolic pathway from MTBE to tert-butyl alcohol and finally to CO2, and may result in the increase of the degrading activity of PM1 cell. The purge and trap GC-MS result of the broth in closed systems showed that tea-butyl alcohol, isopronol and acetone were the main intermediate products.

Determination of methyl tert-butyl ether(MTBE) in Chinese fuels by gas chromatography/mass spectrometry and gas chromatography/flame ionization detector

A method was developed to determine the concentration of methyl tert-butyl ether(MTBE) in gasoline, diesel and heating oil by gas chromatography(GC) with mass spectrometry(GC-MS) or flame ionization detection(FID). The diluted gasoline was directly injected into the GC, and the complete separation of MTBE from co-eluting hydrocarbons was not required. GC/MS or GC/FID method can be used to analyze MTBE in different concentration range and have good consistency.

Butyl ether as Co-diluent in medium-concentrated electrolyte for Li-S battery

1. Introduction The Lithium-sulfur battery(LSB) shows promise as a highdensity energy source, with a theoretical energy density of approximately 2600 W h kg^(-1)[1]. However, practical application of the LSB has been hindered by the “shuttle effect” and Li anode corrosion [2,3]. Highly concentrated electrolytes(HCEs) have been proposed as a solution, as they can inhibit the dissolution of lithium polysulfide and promote homogeneous lithium deposition [4].

Separation of the Ternary System of Methanol/ Methyl Butyl Ether/1-Butylchloride

The separation of ternary methanol/methyl butyl ether/1-butylchloride mixtures was investigated, which are the main components of the waste liquid. After preliminary studies on the ternary system, the integrated process of extraction and distillation was put forward to separate the ternary system. The results show that methanol carl be removed from the mixtures by extraction using water as the extracting agent. Through distillation of extract and dried raffinate respectively, methanol, methyl butyl ether and 1-butylchloride can be separated and recovered. In addition, the optimal volume for the extracting agent and effects of reflux ratio on the yield of product were also studied. The optimal volume ratio of the extracting agent to material is 1： 3.5, and the yield of the product increases with the increase of reflux ratio.

Superior gallstone dissolubility and safety of tert-amyl ethyl ether over methyl-tertiary butyl ether

BACKGROUND The use of methyl-tertiary butyl ether(MTBE)to dissolve gallstones has been limited due to concerns over its toxicity and the widespread recognition of the safety of laparoscopic cholecystectomy.The adverse effects of MTBE are largely attributed to its low boiling point,resulting in a tendency to evaporate.Therefore,if there is a material with a higher boiling point and similar or higher dissolubility than MTBE,it is expected to be an attractive alternative to MTBE.AIM To determine whether tert-amyl ethyl ether(TAEE),an MTBE analogue with a relatively higher boiling point(102°C),could be used as an alternative to MTBE in terms of gallstone dissolubility and toxicity.METHODS The in vitro dissolubility of MTBE and TAEE was determined by measuring the dry weights of human gallstones at predetermined time intervals after placing them in glass containers with either of the two solvents.The in vivo dissolubility was determined by comparing the weights of solvent-treated gallstones and control(dimethyl sulfoxide)-treated gallstones,after the direct infusion of each solvent into the gallbladder in both hamster models with cholesterol and pigmented gallstones.RESULTS The in vitro results demonstrated a 24 h TAEE-dissolubility of 76.7%,56.5%and 38.75%for cholesterol,mixed,and pigmented gallstones,respectively,which represented a 1.2-,1.4-,and 1.3-fold increase in dissolubility compared to that of MTBE.In the in vitro experiment,the 24 h-dissolubility of TAEE was 71.7%and 63.0%for cholesterol and pigmented gallstones,respectively,which represented a 1.4-and 1.9-fold increase in dissolubility compared to that of MTBE.In addition,the results of the cell viability assay and western blot analysis indicated that TAEE had a lower toxicity towards gallbladder epithelial cells than MTBE.CONCLUSION We demonstrated that TAEE has higher gallstone dissolubility properties and safety than those of MTBE.As such,TAEE could present an attractive alternative to MTBE if our findings regarding its efficacy and safety can be consistently reproduced in further subclinical and clinical studies.

Methyl tertiary-butyl ether inhibits THP-1 macrophage cholesterol efflux in vitro and accelerates atherosclerosis in ApoE-deficient mice in vivo

The biosafety of methyl tertiary-butyl ether(MTBE),mainly used as a gasoline additive,has long been a contentious topic.In addition to its routine toxicities,MTBE has been demonstrated to disrupt glucose and lipid metabolism and contribute to the development of type2 diabetes as well as obesity.As one of the morbidities related to dyslipidemia,atherosclerosis is worthy of being investigated under MTBE exposure.Since foam cells derived from macrophages play pivotal roles during atherosclerosis development,we studied the effects of MTBE on macrophages in vitro and assessed the effect of MTBE on atherosclerosis plaque formation with the ApoE^(-/-)mouse model in uiuo for the first time.Our results demonstrated that exposure to MTBE at environmentally relevant concentrations decreased the expression of ABCA1 and ABCG1,which are responsible for macrophage cholesterol efflux,at both mRNA and protein levels in THP-1 macrophages.Consequently,treatment with MTBE inhibited the transport of cholesterol from macrophages to High-density lipoprotein.ApoE^(-/-)mice exposed to MTBE at environmentally relevant concentrations(100,1000μg/kg)displayed significant increases in lesion area in the aorta and aortic root compared to vehicletreated ones.Further analysis indicated that MTBE exposure enhanced the macrophagespecific marker Mac-2 contents within plaques in the aortic root,implying that MTBE could promote macrophage-derived foam cell formation and thus accelerate atherosclerosis plaque formation.We for the first time demonstrated the pro-atherogenic effect of MTBE via eliciting disruption of macrophage cholesterol efflux and accelerating foam cell formation and atherosclerosis plaque development.

Zeolite-assisted etherification of glycerol with butanol for biodiesel oxygenated additives production

This research was focused on the valorisation of glycerol,exploring the feasibility of an efficient route for oxygenated additives production based on its etherification with bio-butanol.A home-made BEA zeolite sample with a tuneable acidity has been proposed as the catalytic system,being tested in a stirred reactor under different etherification conditions.Although a reaction temperature as high as 200℃resulted to be beneficial in terms of glycerol conversion(-90%),only by operating at milder conditions the product selectivity to glycerol-ethers can be better controlled,in order to obtain a bio-fuel complying with the requirements for mixing with fossil diesel or biodiesel,without any need of purification from large amount of by-products.A comprehensive identification of all the compounds formed during the reaction was performed by a GC-MS analysis,on the basis of the complex network of consecutive and parallel reaction paths leading not only to the desired ethers,but also to many side products not detected in similar acid-catalyzed reactions in liquid phase and not available in the most used mass-spectra libraries.

环境中MTBE复合污染的好氧微生物降解研究进展

甲基叔丁基醚(Methyl tert-butyl Ether,MTBE)在过去几十年里一直作为汽油添加剂被广泛使用。MTBE经常与其他汽油组分经由燃料泄露、机动车尾气排放等途径一起进入环境中,造成复杂的持久性复合污染。微生物好氧降解是一种成本低廉、环境友好且应用广泛的有效治理技术,但不同污染物之间存在如共代谢、抑制、交叉诱导等相互作用会影响目标污染物去除。本文总结了好氧微生物降解技术在MTBE与烷烃、芳香烃、重金属等污染物组成的二元复合污染中的应用案例,分析其降解效果和作用机理。研究结果表明:相较于单一菌株,混合菌群具有多样化的群落结构与较高的稳定性,不同菌株之间的协同作用有助于污染物的去除。微生物的生物量也是影响降解效果的重要因素,通过固定化技术可以维持或者提高生物量,从而进一步强化污染物降解。目前,MTBE仍是我国主要的汽油防爆剂且其造成的环境污染长期存在,因此,筛选降解效率更高的菌株,设计更高效的复合污染生物治理方案以及探寻微生物降解复合污染机理是未来研究的重点。

聚羧酸超塑化剂的制备及性能研究

为实现混凝土中水泥等材料的高效分散,以乙烯基丁基聚氧乙烯、丙烯酸等大单体为主要材料,添加金属氧化物助剂、烯丙基磺酸钠小分子单体以及H_(2)O_(2)引发剂等材料制备聚羧酸超塑化剂(VPCE)。从丙烯酸用量、引发剂成分、反应温度以及小分子单体种类等方面优化聚羧酸超塑化剂的制备方案。研究表明,VPCE的最优制备方案为:单体烯丙基磺酸钠、丙烯酸、乙烯基丁基聚氧乙烯的合理用量分别为2.50、9.88、90.00 g,最优引发体系为H_(2)O_(2)/ZnO,用量分别为1.50、0.01 g,最优反应温度为20℃,引发剂最佳滴加时间为45 min。最优方案制备的聚羧酸超塑化剂,水泥净浆的流动度可达到283 mm。

加油站地下水中甲基叔丁基醚污染特征

为研究加油站地下水中甲基叔丁基醚(MTBE)的污染特征,对上海市14个行政区71个加油站周边地下水中的MTBE进行为期1年的系统监测及健康风险评估。结果表明,上海市各区加油站地下水中MTBE普遍有检出,检出质量浓度在ND~11919μg/L(ND表示未检出),且各点位的MTBE浓度差别较大。在71个点位中,MTBE的检出点位数有59个,超标点位数有24个,总检出率、总超标率分别为83.1%、33.8%。从第1~4季度,MTBE的检出率和超标率都呈增长趋势,表明地下水中MTBE的污染程度逐渐增强。同时,地下水中MTBE浓度和石油烃浓度呈显著正相关关系,说明MTBE污染很可能源于油品存储、使用过程的泄漏。对24个MTBE超标点位进行健康风险评估结果显示,从第1~4季度,共计有11次MTBE的浓度已超健康风险临界值,可能对人体健康造成风险,有2次的MTBE浓度在临界值附近,需警惕。随着时间推移,MTBE对人体健康造成的风险正逐渐增加。此外,对地下水中MTBE浓度进行了风险评估,确定MTBE风险控制值为1.9μg/L。

胺液脱硫系统顽固性发泡的原因及对策

为解决中国海油宁波大榭石化有限公司胺液脱硫系统存在顽固性发泡问题,对发泡原因进行了分析,并提出了相应的对策。结果表明:胺液中的大分子烃类和组成复杂的聚合物成分经长时间积累是形成顽固性发泡体系的主要原因;催化裂解干气和气柜气携带的柴油组分是大分子烃类的主要来源,来自上游催化裂解装置液化气中的1,3-丁二烯是聚合物主要来源。采用河北精致科技有限公司开发的减压蒸馏工艺,实现了胺液在线净化处理,净化后胺液的发泡高度不高于4 cm,消泡时间不长于5 s,油质量浓度不大于100 mg/L,胺液清澈透明,可将甲基叔丁基醚含硫量降至45μg/g以下。

催化裂解装置回炼醚后C_(4)馏分增产甲基叔丁基醚

为了充分利用C_(4)资源增产甲基叔丁基醚(MTBE),在中海石油宁波大榭石化有限公司催化裂解(DCC)装置上通过回炼醚后C4馏分,考察回炼醚后C_(4)馏分前后装置操作参数、物料平衡、产品分布、产品性质、能耗等的变化。结果表明:DCC装置回炼醚后C4(6.88 t/h)和气分C_(4)(10.06 t/h)后,一部分异丁烷和正丁烷组分在系统中循环,气分C4中异丁烯体积分数由31.48%降至29.83%,液化气、乙烯收率分别增加1.18,0.11个百分点,丙烯收率下降0.09个百分点,装置能耗(以标准油计,下同)增加0.24 kg/t;MTBE装置加工负荷增加17.93个百分点,MTBE产量增加2.69 t/h,收率增加1.16个百分点,醚后C_(4)出装置量降低2.56 t/h,装置能耗降低4.78 kg/t。

2023年甲基叔丁基醚市场分析及预测

以2019-2023年数据为基础,对我国甲基叔丁基醚的生产建设、市场供需、价格、进出口贸易量及方式进行了详细分析和预测,指出,未来我国甲基叔丁基醚出口量或将保持在百万吨以上水平,进口量保持低位。

次氯酸钙氧化降解乙二醇丁醚及其机理研究

采用次氯酸钙氧化处理含乙二醇丁醚废水,研究了反应pH、反应温度、次氯酸钙用量和反应时间对乙二醇丁醚氧化降解效果的影响,并且探讨了氧化降解机理。研究结果表明最优工艺条件为:反应pH值为5、反应温度为50℃、次氯酸钙用量为2%、反应时间为180min。在该条件下出水COD可降低68.6%,TOC去除率为41.5%。出水有机成分分析表明,乙二醇丁醚逐步断链、脱碳、加氯,分解为较短碳链氯代烯烃、醇类等中间产物,最终被降解为CO_(2)和H_(2)O。

甲基叔丁基醚(MTBE)对莱茵衣藻的毒性效应研究

通过暴露实验,探究MTBE对莱茵衣藻的急性毒性效应,并通过流式细胞术探究MTBE暴露下莱茵衣藻的细胞形态和叶绿素含量的变化。结果表明,MTBE对莱茵衣藻的急性毒性较小,中高浓度(1000~10000 mg/L)下莱茵衣藻的生长被显著抑制,72 h和96 h EC_(50)分别为3896.15 mg/L和2554.00 mg/L。细胞形态学上,10000 mg/L的MTBE暴露下,莱茵衣藻在24~96 h表现出细胞体积减小;所有浓度处理组呈现出细胞颗粒度降低的趋势,表明莱茵衣藻细胞结构受到MTBE的破坏。莱茵衣藻在10000 mg/L的MTBE暴露下叶绿素含量显著下降,表明叶绿素合成功能或受损伤。MTBE引起的细胞形态和叶绿素合成功能的损伤会直接影响莱茵衣藻的生长繁殖和种群数量,进而对水生态系统产生潜在风险。本研究结论可为MTBE的安全使用和合理排放提供参考依据。

甲基叔丁基醚对生态与环境的影响

汽油添加剂甲基叔丁基醚 (MTBE)因能提高辛烷值、减少尾气污染物而被广泛使用。虽然MTBE对改善空气质量有积极意义 ,但因其泄漏并具有稳定性、迁移性和毒性 ,对水环境和人类造成危害。笔者综述了MTBE的毒性和对生态环境的影响 ,介绍了MTBE污染的防治现状 。

乙基叔丁基醚(ETBE)的催化反应动力学研究

用国产 S型强酸性阳离子交换树脂为催化剂 ,在常压液相条件下用乙醇 (Et OH)和叔丁醇 (TBA)合成了乙基叔丁基醚 (ETBE)。讨论了温度、催化剂浓度、反应物初始摩尔比等参数对反应速度的影响 ,考察了水对反应的阻害效应以及反应体系的体积变化原因 ,建立了一个反应动力学模型 。

乙基叔丁基醚合成反应动力学

乙基叔丁基醚一般由乙醇和异丁烯合成，以阳离子交换树脂为催化剂．研究了外扩散阻力为零时的合成反应宏观动力学模型．其本征动力学采用广义Langmuir-Hinshelwood速率方程，将反应速率用液相活度系数关联．内扩散用广义Maxwell-Stefen方程描述，以组分的化学位梯度为扩散推动力．本模型较好地描述了非理想反应物系统的吸附特性和扩散过程．用文献中的实验数据对模型作了检验.

乙基叔丁基醚的催化反应与渗透蒸发膜分离耦合法的合成

以乙醇（ＥｔＯＨ）及叔丁醇（ＴＢＡ）为原料，用催化反应与渗透蒸发膜分离耦合的方法，以强酸性阳离子交换树脂Ａｍｂｅｒｌｙｓｔ１５为催化剂，合成了乙基叔丁基醚（ＥＴＢＥ）。研究考察了水－醇体系中水的渗透速率及膜的选择性，讨论了渗透蒸发膜分离耦合与否对其反应结果的影响。在考虑了试验条件下ＴＢＡ分解为水与异丁烯（ＩＢ）而引起的体积减少、水的吸附对催化剂活性的阻害效应以及水的渗透通量等因素的基础上，得出了一数学模型。试验结果与模型计算值比较一致。