2,6-二溴-4-三氟甲氧基苯胺的合成

以4-三氟甲氧基苯胺为原料,经溴化得到2,6-二溴-4-三氟甲氧基苯胺。研究了溴化剂(液溴、液溴-双氧水)和溶剂(二氯甲烷、三氯甲烷-水、二氯甲烷-水)等因素对产量、纯度及成本的影响。结果表明,最佳工艺条件为:使用液溴-双氧水作溴化剂,液溴与4-三氟甲氧基苯胺摩尔比为1∶1,二氯甲烷-水作反应溶剂,回流反应,产率可达97%,纯度>99.5%。     

离子液体中合成2-溴-4-甲氧基苯胺的研究

研究了在离子液体中对甲氧基苯胺经溴化合成2-溴-4-甲氧基苯胺的方法.以98.2％的收率得到质量分数为99.5％的2-溴-4-甲氧基苯胺.探讨了不同溴化剂及其用量、反应温度、反应时间等因素对溴化反应的影响.该方法原料易得,反应条件易于控制,收率高,离子液体可以重复使用,对环境友好.     

C.I.分散黄71的合成技术

以1,8-萘二甲酸酐和2-硝基-4-甲氧基苯胺为原料,用水作为溶剂合成了C.I.分散黄71.其总收率可达到88％,高效液相色谱含量可达到99％.得到的产品经应用测试达到国内外同行水平.     

2，6-二溴-4-三氟甲氧基苯胺的合成

介绍一种在水和非水溶性有机溶剂组成的两相溶剂中，以对三氟甲氧基苯胺为原料，与溴素发生溴化反应，得到2，6-二溴-4-三氟甲氧基苯胺的方法，该产品以游离形式溶解在有机溶剂中，直接分离，生成的溴化氢完全溶解在水中，该工艺非常适合工业化生产。     

3,4-二甲氧基苯胺的合成

以3,4-二甲氧基苯为原料。在0-5℃低温条件下,以硝酸和硫酸按比例配成的混酸进 行硝化,反应结束后过滤得到3,4-二甲氧基硝基苯,该步反应的收率有97％。然后以乙醇为溶剂, 雷尼镍为催化剂,在1．6 MPa的氢气压力下,于高压釜中100℃条件下通过催化加氢将3,4-二甲氧 基硝基苯还原为3,4-二甲氧基苯胺。该反应的收率达到90％以上,纯度达到98％以上。     

2-羟基-4-甲氧基苯乙酮席夫碱化合物的合成

以2-羟基-4-甲氧基苯乙酮与3-硝基苯胺为原料，在一定条件下，通过加成-脱水反应制备2-羟基-4-甲氧基苯乙酮席夫碱，探讨了合成反应的影响因素，利用元素分析、红外光谱确定其结构，产品的收率为84％。     

3—氯—4—甲氧基苯胺的杂质去除与提纯

<正> 3-氯-4-甲氧基苯胺是制造除莠剂—N-C3-氯-4-甲氧基苯)-N’和N’-二甲基脲的半成品,在异丙醇的介质中,还原3-氯-4硝基甲苯即可制得。通常合成产品中含有N-异丙基-3-氯-4-甲氧基苯胺,其含量有时可达10％以上。 3-氯-4-甲氧基苯胺的提纯方法包括工     

2-硝基苯胺-4-磺酸的合成研究

以溶剂汽油和石油醚按一定比例复配成混合型溶剂,用该溶剂合成了2-硝基苯胺-4-磺酸。产品收率在的91％以上,溶剂回收率在95％以上。     

C．I．分散蓝257及其中间体的合成

研究了以间乙酰氨基苯胺和对甲苯磺酸-β-甲氧基乙酯为原料,在缚酸剂氧化镁的作用下合成间乙酰氨基-N,N-二（β-甲氧基乙基）苯胺的工艺路线,然后与2-氰基-4-硝基-6-溴苯胺的重氮盐偶合反应合成C．I．分散蓝257,总收率80％,并对产品进行上染性能测试。合成中间体间乙酰氨基-N,N-二（β-甲氧基乙基）苯胺较佳工艺条件为：水与对甲苯磺酸-β-甲氧基乙酯及间乙酰氨基苯胺摩尔比为10：2、2：1,且采用分段升温。     

2-甲基-4-甲氧基二苯胺的合成

研究了以邻硝基甲苯为原料,经以Pt/C催化加氢和烷基酮、Pd/C存在下缩合两步合成2-甲基-4-甲氧基二苯胺（DPA）,收率分别为71.2％和96.1％。     

Purification of cholesterol from lanolin by column chromatography

采用柱层析法分离羊毛脂中的胆固醇,以胆固醇与杂质羊毛甾醇的分离度为判定依据来筛选吸附剂及优化层析工艺,同时对吸附剂进行了再生考察。实验表明,当以200～300目粗孔硅胶为吸附剂、丙酮/正己烷混合溶剂（体积比4∶96）为流动相、35 ℃下胆固醇上载量为2.4%（质量分数）时,胆固醇的分离效果较好,所得胆固醇含量可达84.36%,收率为85.67%。另外选用丙酮/正己烷混合溶剂（体积比50∶50）对吸附剂进行再生处理,硅胶经7次使用再生循环,分离效果未降低。     

Preparation of high purity methylal by extractive distillation using N,N-dimethylformamide (DMF) as solvent

通过溶剂选择原理粗选出萃取精馏制备甲缩醛产品的溶剂,既而通过Chemcad软件模拟和汽液平衡实验确定合适的溶剂及溶剂比。结果表明,N,N-二甲基甲酰胺（DMF）能够消除甲缩醛-甲醇共沸物系的共沸点;采用UNIQUAC模型对常压下甲缩醛-甲醇物系和加入溶剂N,N-二甲基甲酰胺的汽液平衡进行模拟,模拟结果和实验数据吻合较好。用间歇萃取精馏实验对甲缩醛粗品进行了分离,在实验条件下,可以从塔顶得到质量浓度为99.9%的高纯度甲缩醛产品。     

5-氟-6-乙基-4-羟基嘧啶的合成

以α-氟代丙酰乙酸甲酯为原料,用氨化和环合的"一锅法"合成了伏立康唑的关键中间体———5-氟-6-乙基-4-羟基嘧啶;最优的反应条件为:以甲醇钠作为碱,氨气作为氨化试剂,甲醇作为反应溶剂,先在室温下搅拌反应5 h,然后加入甲酰胺后回流搅拌反应5 h,两步总收率63%。     

Separation of fish oils ethyl esters by means of supercritical carbon dioxide: Thermodynamic analysis and process modelling

A semicontinuous fractionation process of fish oil ethyl esters was carried out in this work by means of supercritical carbon dioxide. The process focused on the separation of ethyl esters on chain length basis. Experimental temperature ranged from 42 to , whereas pressure ranged from 10.1 to 17.2 MPa. Optimal operating conditions were found for solvent density in the range 570-. A thermodynamic model based on the Peng-Robinson equation of state, proposed to represent high-pressure phase equilibria for this complex system, was validated on the experimental data. The model assumes that the multicomponent natural mixture can be considered as composed of five major components, defined on chain length basis. The proposed thermodynamic model was then used in the modellization of a continuous multistage fractionation process. The continuous process simulations that were carried out allowed to investigate the effect of number of theoretical stages, reflux ratio and solvent to feed ratio on the distribution of the components between extract and raffinate. A case study was considered, in order to find out process operating conditions to attain 95% by weight of heavy components (acid chain length 20 and 22) in the raffinate together with a 95% recovery. Results show that the stated separation is possible with a solvent to feed ratio and a number of theoretical stages in the range 90-150 and 11-30, respectively. The simulations were also employed to study the effect of the operating conditions of the separator used for solvent recycling.     

Methyl acetate–methanol mixture separation by extractive distillation: Economic aspects

Methyl acetate is considered low toxicity volatile solvent produced either as a by-product during methanol carbonylation or via acetic acid esterification with methanol. In both cases, pure methyl acetate has to be isolated from the reaction mixture. Simulation of methyl acetate separation from its mixture with methanol by extraction distillation was carried out in ASPEN + software. In total three case studies were assumed using two different extraction solvents and two solvent regeneration strategies. In case A, novel extraction solvent 1-ethyl-3-methylimidazolium trifluoromethanesulfonate ionic liquid, was considered. Raw material separation was achieved in an extraction distillation column while the solvent regeneration was accomplished in a second distillation column in this case. In case study B, the same extraction solvent was used; however, its regeneration was carried out in a single-effect evaporator. Dimethyl sulfoxide was the second extraction solvent selected. Its use in methyl acetate-methanol separation is presented in case study C. As high purity of dimethyl sulfoxide was required for the methyl acetate-methanol azeotrope breaking, its regeneration was carried out in the second distillation column only. To simulate the ternary methyl acetate–methanol–extraction solvent mixtures separation, vapor–liquid equilibrium was predicted based on the NRTL equation. Further, unknown properties of the considered ionic liquid and variation of these properties with temperature were predicted and introduced into the ASPEN + components properties database. Based on these data, optimum operation parameters of the respective separation equipment were established. In all case studies, the same condition had to be fulfilled, namely minimum methyl acetate content in the distillate from the extraction distillation column of 99.5mol-%. Results of simulations using the respective optimum operation parameters were employed in the economic evaluation of the three separation unit designs studied. It was found that the least energy-demanding design corresponds to the case study B in terms of both capital as well as operation expenses.

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Ultrafine Electrospun Polyamide‐6 Fibers: Effects of Solvent System and Emitting Electrode Polarity on Morphology and Average Fiber Diameter

Summary: In the present contribution, polyamide‐6 (PA‐6) solutions were prepared in various pure and mixed‐solvent systems and later electrospun with the polarity of the emitting electrode being either positive or negative. The PA‐6 concentration in the as‐prepared solutions was fixed at 32% w/v. Some of the solution properties, i.e., shear viscosity, surface tension, and conductivity, were measured. Irrespective of the polarity of the emitting electrode, only the electrospinning of PA‐6 solution in formic acid (85 wt.‐% aqueous solution) produced uniform electrospun fibers, while solutions of PA‐6 in m‐cresol or sulfuric acid (either 20 or 40 wt.‐% aqueous solution) did not. In the mixed‐solvent systems, formic acid (85 wt.‐% aqueous solution) was blended with m‐cresol, sulfuric acid (either 20 or 40 wt.‐% aqueous solution), acetic acid, or ethanol in the compositional range of 10–40 vol.‐% (based on the amount of the minor solvent). Generally, the average fiber diameter increased with increasing amount of the minor solvent or liquid. Interestingly, the diameters of the fibers obtained under the negative electrode polarity were larger than those obtained under the positive one.

Optical images of electrospun fibers from solutions of polyamide‐6 in a mixed solvent of 85 wt.‐% formic acid and 20 vol.‐% m‐cresol under positive (left) and negative (right) electrode polarity.     

Evaluation of double extraction techniques as solubility tests for fertiliser products containing phosphate rock components

Alternative extraction techniques for assessing the available P content in multi-component fertilisers such as partially acidulated phosphate rocks have been examined. Two types of double extraction method have been investigated, one involving sequential extraction procedures, and a second examining both the initial fertiliser and its residue independently, using either water or cold neutral ammonium citrate as the first extractant, and either 2% citric or 2% formic acid as the second solvent. The latter method, which used cold neutral ammonium citrate as the initial extractant, produced the most consistent results and provided a reproducible assessment of the solubility of the phosphate rock residue; it was not obvious which second solvent was preferable. Comparisons between the original phosphate rocks and their extracted residues indicated that there were many subtle influences which affected the solubility of the phosphate rock components, but a general deactivation of phosphate rock residues on acidulation as previously suggested was not apparent. Before any particular method can be recommended as an alternative to existing one step extraction techniques it is necessary to confirm its validity through agronomic trials.     

2,4,6,4′-四羟基脱氧安息香的合成

利用均苯三酚和对羟基苯乙酸为原料,新蒸馏三氟化硼乙醚为催化剂和溶剂,"一锅法"合成2,4,6,4′-四羟基脱氧安息香;通过改进工艺条件;均苯三酚与对羟基苯乙酸摩尔比为5.1∶5,25°C条件下,反应3.5 h产率达到60%以上。     

Continuous stable enantioselective hydrogenation of alkyl pyruvate esters using pre-modified cinchonidine platinum catalysts

Pre-modification of a 5 wt% Pt/-Al₂O₃ catalyst with cinchonidine (0.1 g g^–1 catalyst) leads to a catalyst that give stable enantioselection when using a trickle-bed flow reactor at ambient temperature and pressure. With dichloromethane as solvent sustained enantiomeric excess of >70% for the hydrogenation of ethyl pyruvate to (R)-ethyl lactate is observed and this is maintained with very low cinchonidine/catalyst ratios. With dichloromethane the conversion decreases with time an effect we consider to be due to the formation of small amounts of polymer on the catalyst surface. When ethanol is used as solvent the yield of (R)-ethyl lactate is stable throughout the test period, although the enantiomeric excess was much lower at ca. 35%.