2-乙基己基磷酸单脂萃取分离钴镍镁试验研究

对Ｐ５０７（２－乙基己基磷酸单脂）萃取分离钴镍镁进行试验研究和Ｐ５０７分离钴镍镁效果很好。钴的直接收率达８１％,回收率达９９％,而且萃取过程无污染,其效果优于使用Ｐ２０４和氟化铵。     

海水萃取除钙,镁的研究初探

研究了用「二（２－乙基己基）磷酸」（Ｐ２０４）－苯萃取除海水中的钙、镁离子的机理，探讨了用萃取法除海水中钙、镁离子制取制碱化盐用沙工业循环用水的可能。     

超临界CO_2从南海翡翠贻贝中萃取EPA和DHA的研究

用超临界ＣＯ２对南海翡翠贻贝中萃取二十碳五烯酸（ＥＰＡ）和二十二碳六烯酸（ＤＨＡ）工艺进行了研究,得出其最佳工艺条件为：压力３５ＭＰａ,温度３５℃,ＣＯ２用量２ｍｌ／ｇ料,尿素用量为乙酯量的１０％。乙酯的萃取率达到６１．５％。ＥＰＡ和ＤＨＡ乙酯总含量（ｗ）达到２８３２％。     

从含钼的P204—煤油体系中反萃取钼的研究

从含钼的Ｐ２０４—煤油体系中反萃取钼的研究俞宏伟陈虹（浙江巨化集团公司巨大化工厂衢州市３２４００７）刘润张勇（华东理工大学化学系上海市２００２３７）１前言在钼的湿法冶金以及从含钼废物中提取钼的工艺流程中，萃取法有着广泛的应用。常用的萃取流程是以Ｐ２０...     

超临界CO_2从小球藻中萃取EPA和DHA的工艺研究

研究采用超临界ＣＯ２从小球藻中萃取ＥＰＡ和ＤＨＡ的最优化工艺条件（Ａ２Ｂ１Ｃ３Ｄ３）,得最高萃取率ＥＰＡ为８９．７％、ＤＨＡ为８８．１％,该法比溶剂法优越,为开发和综合利用海藻资源开辟了新的途径     

二（2—乙基己基）磷酸萃取L—异亮氨酸的研究

以二（２－乙基己基）磷酸（Ｄ２ＥＨＰＡ）－正辛烷及Ｄ２ＥＨＰＡ－正辛醇萃取Ｌ－异亮氨酸为对象,研究了Ｄ２ＥＨＰＡ浓度、Ｌ－异亮氨酸初始浓度以及ｐＨ值对萃取平衡分配系数的影响。结果表明,在实验研究涉及的ｐＨ值范围内,分配系数先随ｐＨ的增加而增大,在３．５〈ｐＨ〈５区域,ｐＨ值对分配系数的影响较小。分配系数还随Ｄ２ＥＨＰＡ浓度的增加而增大。正辛醇加入有机相,萃取分配系数增大。Ｄ２ＥＨＰＡ与Ｌ－异亮氨酸     

单级萃取—反萃取同时分离回收磷酸中铀和稀土

使用单级萃取－反萃取工艺，从湿法磷酸（ＷＰＡ）中回收铀和稀土的新工艺，既简单又易于控制，因为它只涉及酸性介质。该工艺是基于用二（２－乙基己基）磷酸（ＤＥＰＡ）和磷酸三丁酯（ＴＢＰ）和磷酸三丁酯（ＴＢＰ），从湿法磷酸中萃取铀和稀土。发现ＤＥＰＡ是唯一有效的，它稳定并且易于反萃取。其它的有机磷酸酯易水解，并且很难反萃取。用含有酸性氟化物的介质，对稀土和铀进行反萃取。对于铀来说，以六价（Ｕ＾６＋）形成被     

苯乙烯磷酸单1－甲基庚基酯对锌（Ⅱ）和镉（Ⅱ）的萃取

分别测定了锌（Ⅱ）和镉（Ⅱ）在苯乙烯膦酸单１—甲基庚基酯［ＨＭＨｅ（ＳＰ），Ｂ３１７］以及二－２－乙基己基磷酸（ＨＤＥＨＰ，Ｐ２０４）的正辛烷溶液与硝酸钠水溶液间的分配。     

P204液膜体系分离和富集Fe^3＋的传质机理

通过萃取－反萃取实验确定了Ｐ２０４液膜体系萃取和反萃取Ｆｅ３＋的化学方程式，从而确定了该液膜体系的传质机理。     

新型香料N-（2，5-二甲基吡咯）亮氨酸异辛酯的合成及加香应用研究

分别以亮氨酸和2,5-己二酮为原料,通过Paal—Knorr反应合成了化合物1（N-（2,5-二甲基吡咯）亮氨酸）,接着以二环己基碳二亚胺（DCC）为缩合剂,4-二甲氨基吡啶（DMAP）为催化剂,使其和异辛醇发生缩合酯化反应,得到新化合物2（N-（2,5-二甲基吡咯）亮氨酸异辛酯）。通过IR、1HNMR、13CNMR、HRMS等波谱方法对产物结构进行了确证。并研究了化合物2在300℃、600℃和900℃的热裂解行为,分析鉴定出了65种裂解产物,其中含有多种致香物质。卷烟加香结果表明,当N-（2,5-二甲基吡咯）亮氨酸异辛酯的添加量达到0．02％时,能有效改善卷烟吸味,增强香气。     

Cloud Point Extraction of α-Amino Acids

Cloud point extraction with a polyethoxylated alcohol (Oxo-C₁₀E₄) is used to separate five α-amino acids: alanine, valine, leucine, isoleucine, and phenylalanine (0.75 wt.% in water), and their extraction efficiencies are compared. The variables affecting phase separation and extraction (wt.% surfactant and equilibrium temperature) are optimized using experimental design. The four responses are: percentage of solute extracted (E), residual concentrations of solute (amino acid) and surfactant in the dilute phase, and volume fraction of coacervate at equilibrium. E increases with surfactant concentration and amino acid hydrophobicity in the following order: alanin < valin < leucin < isoleucine < phenylalanine, with respective maximum values: 73, 74, 76, 78.5, and 95%, and decreases with a temperature rise. It also makes sense that aspartic and glutamic acids, much more hydrophilic, are poorly extracted (E ? 10%). The trend observed is consistent with water/n-octanol partition coefficient (Log P) of amino acids in pure water. A more detailed study is presented for alanine and phenylalanine. Addition of sodium sulphate or cetylammonium bromide greatly raises extraction rates.     

从石煤酸浸液中萃取钒的实验研究

以陕西山阳石煤钒矿作为研究对象,实验研究了磷酸二异辛酯(P204)对硫酸浸出溶液体系中钒的萃取工艺。主要考察了P204体积分数、pH值、萃取时间、萃取级数及有机相与水相体积比等因素对钒萃取率的影响。确定了萃取的最佳工艺参数:P204体积分数20%,磷酸三丁酯(TBP)5%,磺化煤油75%,萃取平衡pH值在2.5左右,相体积比为1∶5,萃取时间为5 min,萃取级数为5级。在此条件下萃取含钒2.965 8 g/L溶液,萃取率可达98.57%。     

皂化P204微乳液膜处理含锌废水的研究

研究以皂化P204为载体的微乳液膜配方及其稳定性.采用P204/Span80/煤油/NaOH微乳体系萃取废水中Zn^2＋,考察了P204与煤油和Span80的质量比、NaOH的浓度、乳水比、外水相pH值、油相重复使用次数等因素对Zn^2＋萃取率的影响.结果表明,当P204与煤油的质量比为1：2.5,P204与Span80的质量比为1：1,NaOH浓度为1.5mol/L,乳水比为1：4（体积比）,废水pH值为5.5时,萃取10min,P204/煤油/NaOH微乳液膜对Zn^2＋萃取率可达99.72%,P204/Span80/煤油/NaOH微乳液膜对Zn^2＋萃取率可达99.98%,微乳液膜不仅稳定性好、萃取效率高,而且工艺简单、膜相可自动破乳、油相可重复使用.     

Leucine as an in vitro precursor to lipids in rat sciatic nerve

The in vitro incorporation of leucine, isoleucine and pyruvate into lipids was compared and the possibility that leucine might serve as anin situ precursor to the correspondingiso fatty acids in the rat sciatic nerve was studied. The relative incorporation of¹⁴C from leucine into lipids vs. nonlipids was 20%, and the incorporation of label into total lipids from leucine was one-half that from pyruvate. The incorporation of label from leucine and pyruvate into sterols was nearly equivalent, but the incorporation of label into all other lipid classes from leucine was less than that from pyruvate, and the incorporation of label from isoleucine into lipids was much less in all cases. No detectable label from leucine was incorporated into brached chain fatty acids. It is concluded that leucine may be a substantial in vitro precursor to all major lipids in peripheral nerve, especially sterols. The possibility and significance of a leucine catabolic pathway in the cytosol in relation to availability of 3-hydroxy-3-methylglutaryl CoA for sterol biosynthesis is discussed.     

含金属离子赖氨酸水溶液的萃取分离

采用二(2-乙基己基)磷酸(P204)作萃取剂,航空煤油作稀释剂,对含有钙、镁、钠、钾等金属离子的赖氨酸水溶液进行萃取,以蒸馏水作为反萃取剂对有机相进行反萃取分离实验.结果表明,原料液初始pH值在4～5、P204与煤油体积比为3:2、有机相与水相比为2:1、反应萃取时间大于30min、搅拌转速约200rpm时,能够取得较好的萃取效果.以初始pH值≥3.5的蒸馏水为反萃取剂,蒸馏水与有机相体积比4:1,在150rpm的转速下搅拌20min能够较为完全地分离出赖氨酸,然后在其它条件相同的情况下,用初始pH＜1的蒸馏水对有机相再次反萃取可分离出金属离子,从而实现萃取剂的重复利用.     

乳状液膜法分离富集废旧镍镉电池中的镉

该文介绍了乳状液膜法分离富集废旧镍镉电池中的镉离子。乳状液膜主要由溶剂(煤油)、表面活性剂(Span80)、载体〔二(2-乙基己基)膦酸,P204〕和内水相氨水组成。对影响镉离子渗透和分离过程的重要变量进行了考察,分析了乳状液膜的载体体积分数、外水相pH、搅拌时间、乳水比(乳液与外水相体积比)及Span80体积分数对镍镉分离效果的影响,从而选择出最佳的分离条件为:φ(P204)=4.4%,φ(Span80)=8.8%,pH=5.5,乳水比0.5,搅拌时间10min。用此乳状液膜进行100L反应釜的工业放大实验,镉的迁移率可达93.3%,而镍的迁移率仅为14.6%。     

P_(204)/Span80/煤油/NaOH微乳体系萃取分离Ni~(2+)的研究

研究了以皂化P204和Span80为混合表面活性剂的微乳液配方及其稳定性,通过P204/Span80/煤油/NaOH微乳体系萃取分离N i2+的研究,考察了P204与煤油和Span80的质量比、NaOH的浓度、乳水比、外水相pH值、油相重复使用次数等因素对N i2+萃取率的影响。结果表明,当P204与煤油的质量比为1∶2.5,P204与Span80的质量比为1∶1,NaOH浓度为1.5 mol/L,乳水比为1∶5(体积比),废水pH值为5.5时,萃取10 m in,该微乳体系对N i2+萃取率可达99.9%。该微乳体系具有稳定性好、工艺简单、成本低、萃取效率高等优点。     

Stabilization of bzip peptides through incorporation of fluorinated aliphatic residues

Two fluorinated amino acids, 5,5,5-trifluoroisoleucine (5TFI) and (2S,3R)-4,4,4-trifluorovaline (4TFV), which have been shown to serve as isoleucine surrogates in protein synthesis in Escherichia coli, have been incorporated in vivo into basic leucine zipper (bzip) peptides derived from GCN4. The extents of residue-specific incorporation of 5TFI and 4TFV were 90 and 88 %, respectively, of the encoded isoleucine residues, as evidenced by MALDI mass spectrometry and amino acid analysis. Both circular dichroism and equilibrium sedimentation studies of the fluorinated bzip peptides indicated preservation of secondary and higher-order protein structure. Thermal-denaturation experiments showed an increase of 27 degrees C in melting temperature when isoleucine was replaced by 5TFI. However, the T(m) of the peptide containing 4TFV was increased by only 4 degrees C over that of the peptide containing valine. Similar trends were observed in chemical denaturation studies in which DeltaDeltaG(unfold) in water was determined to be 2.1 or 0.3 kcal mol(-1) upon incorporation of 5TFI or 4TFV, respectively. When the fluorinated peptides were tested for DNA binding, both their affinity and specificity were similar to those of the respective hydrogenated peptides. These results suggest that fluorinated amino acids, even when introduced into the same positions, can have markedly different effects on the physical properties of proteins, while having little impact on secondary and higher-order structure.     

Lipogenesis in the developing brain: Utilization of radioactive leucine,isoleucine, octanoic acid and β-hydroxybutyric acid

Incorporation of radioactivity from intracranially injected radioactive leucine, isoleucine (ketogenic amino acids), octanoic acid and β-hydroxybutyric acid into the brain lipids of 15 to 16 day-old rats was examined. The results showed that radioactivity from all the above precursors was incorporated into brain lipids. Radioactivity from injected isoleucine was incorporated into odd numbered fatty acids indicating an alternate pathway to α-oxidation for the biosynthesis of these fatty acids in the brain. For some as yet unclear reasons, a substantial portion of the radioactivity from injected octanoic acid was incorporated into free fatty acids. Utilization of these compounds for providing carbon for lipogenesis during development under unstressed normal conditions is discussed.     

有机磷(膦)酸萃取钴和镍的动力学行为比较

依据实验结果和文献数据讨论了有机磷酸类萃取剂萃取钴及镍的动力学行为.结果表明,有机磷酸酸性强,溶入水相的速度快,则萃取速度亦快,钴和镍的萃取速度差异由溶剂交换速度决定.