高效液相色谱法测定汽油中苯胺和N-甲基苯胺的含量

正随着社会经济的发展,汽车已成为人们日常生活中重要的交通工具,拥有汽车的人数逐年增长,对车用汽油的需求量也在不断增加,但由于国内炼油工艺技术的限制,正规炼油厂生产的汽油供不应求,使得大量调和汽油充斥市场。一些调油商在原料价格高涨的背景及利益最大化的驱使下,利用苯胺、N-甲基苯胺等低价的苯胺类添加剂进行油品调和[1],存在很大的质量安全风险,从而造成众多汽油     

电感耦合等离子体原子发射光谱法测定汽油中的铁、锰、铅和硅

正因电感耦合等离子体原子发射光谱法(ICPAES)可同时测定多元素,已广泛应用于溶液中元素的分析。因为对润滑油中磨损金属[1-2],以及汽油[3-4]、原油[5]、柴油和石脑油[6]等样品中杂质元素的检测需求在逐步提高[7],故开发有机进样系统十分必要。油品中典型的一类为汽油,汽油中常常加入一些有机添加剂,如有机锰、有机铅、有机铁等作为抗     

催化裂化汽油脱硫添加剂USY/ZnO/Al2O3的性能评价

 在固定流化床催化裂化装置上，以减压蜡油为原料，对制备的U\r\nSY／ZnO／Al2O3催化裂化汽油脱硫添加剂的性能进行了评价．结果表明\r\n，随着添加剂添加量和剂油比的增加，生成汽油的硫含量降低．在500\r\n℃和剂油比为5的条件下，在FCC平衡催化剂中添加30％的添加剂时，汽\r\n油的硫含量可由不加添加剂时的1230μg／g降低到770μg／g左右．添\r\n加剂的添加量（10％）较低时，对催化裂化产物的分布基本没有影响；\r\n添加30％的添加剂时，焦炭的产率有所增加，但汽油收率基本不变．X\r\nRD表征结果表明，USY／ZnO／Al2O3添加剂中的ZnO对USY的晶相结构有\r\n一定的破坏作用，但随着反应与再生次数的增多，ZnO与Al2O3之间形成\r\n较为稳定的锌铝尖晶石结构，使添加剂的性能趋于稳定．     

半固态汽油添加剂低温下的溶解

一种市售汽油添加剂,常温下是半固态。加少量到一定量汽油中,轻摇即可溶解。但当温度降低到10℃,小晶体颗粒陆续开始析出。温度降到0℃时,溶质基本完全析出,且逐渐形成较大的颗粒团,严重影响了此添加剂在低温环境下的使用。为此我们进行了其延时降凝研究。发现溶液中加入少量具有较强极性可与溶质形成氢键、同时具有与溶剂部分相似结构的化合物异丙醇二甲基甲酰胺等,可使溶质在-15℃以下不析出,保持为均匀溶液。1　实验部分此添加剂的主要成份是分子量较大的软脂酸甘油酯,凝固点19℃。据此,在含溶质5%的条件下加入尽可能少的不同溶剂(下…     

顶空固相微萃取-气相色谱-质谱法测定水中四乙基铅

<正>四乙基铅为神经剧毒物且具有高脂溶性,可以通过吸入、饮入、皮吸等途径摄入,严重危害人体健康[1]。四乙基铅曾被广泛应用于汽油抗震添加剂中,通过机动车尾气排放,加油站无组织排放等方式对环境造成污染[2]。含铅汽油虽已被禁用多年,但近年来,在一些环境水体、土壤甚至人体血液中仍然能检出四乙基铅[2-4]。因此,我国对于环境中四乙基铅的监测还一直非常关注。我国环保部规定地级以     

无铅汽油样品中甲基-叔丁基醚的定量测定

1　引　　言由于含铅汽油给环境带来的不利影响 ,近几年来 ,无铅汽油已开始在我国大范围使用。甲基叔丁基醚 (ｍｅｔｈｙｌｔｅｒｔ ｂｕｔｙｌｅｔｈｅｒ,ＭＴＢＥ)是无铅汽油中的一种常用添加剂 ,可提高辛烷值使汽油燃烧更完全 ,从而减少环境污染。但是 ,ＭＴＢＥ的使用在许多发达国家特别是美国引起了很大争议。这是因为ＭＴＢＥ在自然条件下很难降解 ,在水中的溶解度较高(42 0 0 0ｍｇ/Ｌ) ,由于地下储油罐泄露和汽车尾气的排放 ,环境中尤其是地下水中ＭＴＢＥ的含量正在迅速增加。同时 ,研究发现ＭＴＢＥ存在潜在的致瘤性 ,可破坏小鼠…     

微波消解-微波等离子体炬原子发射光谱法测定无铅汽油中痕量铅的研究

四乙基铅作为一种良好的抗爆添加剂,曾广泛用于汽油生产中,但由于四乙基铅有很强的毒性,目前国际上已停止生产和使用车用含铅汽油,因此在生产车用无铅汽油时严格控制和准确测定铅的含量十分必要.迄今,测定汽油中铅含量的常用方法是铬酸盐容量法^[1]、一氯化碘法^[2]、X射线光谱法^[3]、分光光度法^[4,5]、原子吸收光谱法^[6]和等离子体光谱法^[7].这些方法或操作烦琐,测定时间较长^[4],或灵敏度低^[1～3],或测定误差较大,且在测试中需使用毒性较大的四乙基铅^[5],或所需的氯化甲基三辛基铵不易购买^[6],或处理过程繁琐,且仪器设备昂贵^[7].因此,建立一种简便、快速、灵敏、准确和无毒副作用的测定无铅汽油中痕量铅的方法已显得十分迫切.近年来发展的微波等离子体炬原子发射光谱法^[8]已有商品化仪器问世^[9].本文利用微波等离子体炬原子发射光谱仪研究了无铅汽油中痕量铅的测定方法,并提出用微波消解法预处理无铅汽油样品,将微波消解技术与微波等离子体炬原子发射光谱法相结合,建立了简便、快速、灵敏、准确和无污染的测定无铅汽油中痕量铅的新方法.     

用全氟磺酸离子交换树脂多相催化合成不对称醚

醚类化合物是有机化学工业和医药工业上常用的溶剂。又如甲基叔丁基醚沸点低、辛烷值高可作无铅汽油,特别是高级无铅航空汽油的添加剂。Cottle、Wolff等人曾用硫酸、磷酸、有机金属化合物和聚苯乙烯磺酸型离子交换树脂作催化剂,通过醇和烯烃的加成反应合成了对称的和不对称的醚。本文采用酸性比聚苯乙烯磺酸强,但对反应容器无任何腐蚀,操作简便,无三废的全氟磺酸离子交换树脂(以后简称全氟磺酸)作催化剂,合成了甲基叔丁基醚;乙基叔丁基醚;异丙基叔丁基醚和仲丁基叔丁基醚。     

荧光指示剂吸附法测定汽油中烯烃含量的研究

随着我国汽车拥有量的迅猛发展,汽车尾气污染已成为重要的环境污染之一。该污染是由于汽油中含有铅、芳烃和烯烃,减少污染必须控制汽油中的这3种物质的含量。铅作为主要抗爆剂燃烧后排到大气中,85%直接污染环境;芳烃作为汽油中的高辛烷值组分之一,燃烧会导致尾气中有毒物质的排放,增加发动机燃烧室的沉积,并使尾气排放增加;烯烃作为不饱和烃类物质,有较好的抗爆性,但热稳定性差,容易堵塞发动机喷嘴,因此《车用无铅汽油》[1]国家标准中规定汽油中芳烃含量必须不大于40%,烯烃含量不大于35%。根据我国炼油工艺,大部分炼油企业在生产汽油时芳烃…     

汽油的无铅化及提高汽油辛烷值的途径

烷基铅抗爆剂的使用导致了严重的铅污染,禁止使用含铅汽油,实现汽油的无铅化,已成为人们的共识。目前,实现汽油无铅化的主要途径有二:一是通过改变汽油的基础组分来提高汽油的辛烷值,二是研究开发非铅抗爆剂代用品。     

A carbanion induced synthesis of highly congested pyrazole and imidazole containing heterocycles

An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Selective synthesis of 4,5-dihydroimidazo- and imidazo[1,5-a]quinoxalines via modified Pictet–Spengler reaction

An efficient tandem approach for the selective synthesis of 4,5-dihydroimidazo[1,5-a]quinoxalines 6a–g and imidazo[1,5-a]quinoxalines 7a–h by the reaction of 2-imidazolyl anilines 4a–c with aryl aldehydes 5a–k under mild reaction conditions is described. Introduction of electron releasing alkyl groups in substrates 4a–b was found to be instrumental for the success of the reaction.     

Understanding the Diels-Alder reactivity of 1,2-azaborine analogues

The Diels-Alder reactivity of 1,2-heteroborines (H₄C₄B(H)X, X?=?NH, PH, AsH; O, S, Se) has been computationally explored by means of Density Functional Theory (DFT) calculations. The influence of the HB?=?X fragment on the reactivity of the system has been quantitatively analyzed in detail by means of the so-called Activation Strain Model (ASM) of reactivity. It is found that the interaction between these species and the dienophile is significantly stronger than that computed for their all-carbon isoelectronic counterpart, benzene. In addition, the strain energy plays a key role in the observed reactivity trends. The role of the aromaticity strength of these heteroarenes on the reactivity is also assessed.     

Synthesis of N-substituted carbazolones from α-iodo enaminones via Pd(0)-catalyzed intramolecular coupling under microwave irradiation

A variety of N-aryl and N-alkyl carbazolones were conveniently achieved in good to high yields via Pd₂(dba)₃-mediated intramolecular coupling of N-substituted α-iodo enaminones under microwave irradiation. The Pd(0)-catalyzed cyclization was found to proceed favorably with the more electron-deficient phenyl ring during the reactions involving unsymmetrical N,N-diaryl α-iodo enaminones. This unique property enables the construction of carbazolone skeleton containing nitro substituted benzenoid ring.     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Synthesis of substituted 2,4,5,6-tetrahydrocyclopenta[c]pyrazoles and 2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazoles by intramolecular nitrilimine cycloaddition

Both substituted 2,4,5,6-tetrahydrocyclopenta[c]pyrazoles and 2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazoles have been synthesized by the 3+2 intramolecular dipolar cycloaddition of nitrilimines to alkynes. This cyclization has been extended to more versatile 3-bromo derivatives by the use of alkynylbromides as dipolarophiles.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.