The Effect of Alkyl Substituents on Actinide and Lanthanide Extraction by Diglycolamide Compounds

The effect of the alkyl substituents on amidic N atoms in diglycolamide (DGA) compounds on solvent extraction has been investigated. The solubility in water and n-dodecane, lanthanide loading capacity, and distribution ratios (D) of lanthanides and actinides for various DGA compounds are reported. DGA derivatives with short alkyl chains, for example, methyl and ethyl groups, are very water soluble, while DGA derivatives with long alkyl chains, for example, octyl (TODGA), decyl (TDDGA), dodecyl (TDdDGA), and 2-ethylhexyl (TEHDGA) group are moderately soluble in n-dodecane. DGA derivatives with phenyl substituents have very low solubility in both aqueous and organic solvents, which suggests that these compounds will not be suitable for solvent extraction applications in the HNO₃/n-dodecane systems. The lanthanide loading capacities of DGA extractants correlate with their alkyl chain lengths according to the following order: TDdDGA > TDDGA > TODGA > TEHDGA. The branched-alkyl-chain DGA derivative (TEHDGA) exhibits both lower D and loading capacity than TODGA. The results of masking-effect and solubility tests indicate that TEDGA is the best actinide masking agent among the water-soluble DGA derivatives tested. Actinide and lanthanide extractions using ten DGA compounds in six diluents (nitrobenzene, 1,2-dichloroethane, 1-octanol, chloroform, toluene, and n-dodecane) are also reported; it was observed that lipophilic DGA derivatives with shorter alkyl chains show higher D values.     

双膦胺配体氮原子上取代基的空间和电子效应对于乙烯四聚催化体系的影响

在乙酰丙酮铬、甲基铝氧烷（MAO）、配体三元催化体系中,以乙烯为原料在高压下齐聚生成1-辛烯．主要考察N原子上取代基不同的PNP配体对催化荆活性及1-辛烯选择性的影响结果表明．苯环取代基为3．5-二甲基的配体效果较为理想,其活性达到4990kg／（mol·h）．对1-辛烯选择性为72．31％。PNP配体中苯环取代基上间、对位给电子基团有助于提高催化活性和1-辛烯选择性．而空间位阻较大的基团和吸电子基团则不利于催化反应。     

Immune Modulation by Inhibitors of the HO System

The heme oxygenase (HO) system involves three isoforms of this enzyme, HO-1, HO-2, and HO-3. The three of them display the same catalytic activity, oxidating the heme group to produce biliverdin, ferrous iron, and carbon monoxide (CO). HO-1 is the isoform most widely studied in proinflammatory diseases because treatments that overexpress this enzyme promote the generation of anti-inflammatory products. However, neonatal jaundice (hyperbilirubinemia) derived from HO overexpression led to the development of inhibitors, such as those based on metaloproto- and meso-porphyrins inhibitors with competitive activity. Further, non-competitive inhibitors have also been identified, such as synthetic and natural imidazole-dioxolane-based, small synthetic molecules, inhibitors of the enzyme regulation pathway, and genetic engineering using iRNA or CRISPR cas9. Despite most of the applications of the HO inhibitors being related to metabolic diseases, the beneficial effects of these molecules in immune-mediated diseases have also emerged. Different medical implications, including cancer, Alzheimer´s disease, and infections, are discussed in this article and as to how the selective inhibition of HO isoforms may contribute to the treatment of these ailments.     

The Influence of the Alkyl Chain Length and Steric Effect on Stability Constants and Extractability of Co(II) Complexes with 1‐Alkyl‐4(5)‐methylimidazoles

Abstract

Extraction of Co(II) complexes has been studied with nine derivatives of 1‐alkyl‐4(5)‐methylimidazoles (with R=C₂H₃ to C₁₀H₂₁) from aqueous solution [I=0.5(KNO₃) at 25°C] with toluene, trichloromethane, and 2‐ethyl‐1‐hexanol. Stability constants of the complexes formed in the aqueous phase (β _c ) as well as partition constants (P _c ) of the extracted species were determined. It was demonstrated that both the stability constants and partition constants of the complexes increase with an increasing of the 1‐alkyl chain length. The tetrahedral together with octahedral complexes were formed beginning from the second step of complexation. Furthermore, the influence of the bulkiness of the 1‐alkyl group on separation process of Co(II) from Zn(II) for extractions with toluene and 2‐ethyl‐1‐hexanol were determined.     

Steric requirements for the stimulation of glycosyltransferase activity by lysophosphatidylcholine

1-Palmitoyl-sn-glycerol-3-phosphocholine and 3-palmitoyl-sn-glycerol-1-phosphocholine have been found to be equipotent in the stimulation of membrane-bound glycosyltransferases in microsomes of rat intestinal villus cells. This indicates that the stimulatory effect of lysophosphatidylcholine is not stereospecific, but that it may be related to a specific detergent property dependent upon the peculiar balance of hydrophilic and hydrophobic components in the molecule.     

Steric and Electronic Effects in Basic Dyes. II—Electronic Absorption Spectra of Derivatives of Malachite Green Containing Electron-withdrawing Substituents in the Phenyl Ring

Absorption spectra of several derivatives of Malachite Green containing electron-withdrawing groups in the phenyl ring have been examined. Substituents in the 3- or 4-position modify the position of the first-frequency band to an extent approximately linearly related to the appropriate Hammett substituent constant. Although substituents in the 2-position show an ortho effect, the intensities of the first bands are generally lower than those of derivatives containing electron-donating groups.     

烷基糖苷合成工艺中催化剂体系的研究

利用转糖苷化法合成烷基糖苷,对合成烷基糖苷的催化剂体系做了一定改进,并对催化剂的用量做了研究,确定了合成烷基糖苷的最优催化剂体系。     

葡萄糖酶法生物合成烷基糖苷工艺

采用葡萄糖酶法生物合成烷基糖苷,考察了工艺条件对合成烷基糖苷的影响.结果表明m(水)m(乙醇)=37,反应温度为42℃,反应体系pH=5.8;用此法,葡萄糖苷酶活力最高可达75.2×10-3(mg/mL2.min),产品聚合度d.p.=1.43.探讨了该产品的表面性能.     

高活性酯化催化剂烷基锡酸的研究

以松香树脂酸的酯化反应为例,研究了烷基锡酸对酯化反应的催化作用,系统的探讨了影响反应的各种因素。     

Studies on the Decomposition of Alkyl Hydroperoxides by different catalysts

The catalytic decomposition of cumene, 1-methylcyclohexyl and cyclohexyl hydroperoxides was studied in cyclohexane, cis- and trans-1,4-dimethylcyclohexane and cis-pinane as the solvents. The stearates and the acetylacetonates of manganese, cobalt and chromium, the acetylacetonates of molybdenum and vanadium, n-butyl orthoborate and n-butyl metaborate were used as the catalysts. The chromium-, vanadium-, molybdenum- and boron-containing catalysts brought about some Hock-type decomposition of cumene hydroperoxide and thus proved to be acidic. Of these more of less acidic catalysts only molybdenyl acetylacetonate effected a partially stereospecific hydroxylation of the tertiary C H-bonds in cis- and trans-1,4-dimethylcyclohexane. The well-known selectivity of chromium catalysts for the ketone formation during the decomposition of secondary hydroperoxides is caused by the catalytic oxidatio of secondary alcohols by hydroperoxides in the presence of chromium compounds. In the presence of all the catalysts used the free-radical pathways of the hydroperoxide decomposition predominated, and the attack of the intermediate radicals on the starting hydroperoxide was more important than the attack on the solvent molecules.     

The Influence of Alkyl Chain Length and Steric Effect on the Stability Constants and Extractability of Co(II) Complexes with 1-Alkyl-2-Methylimidazoles

Using the liquid-liquid partition method, the formation of Co(II) complexes with 1-alkyl-2-methylimidazoles (where alkyl = C₄H₉ trough C₁₂H₂₅) at 25°C and at a fixed ionic strength of the aqueous phase (I = 0.5, (HL)NO₃, KNO₃) were studied. Dichloromethane, trichloromethane, and 2-ethylhexanol were used as diluents. The tetrahedral and octahedral complexes were formed. Stability constants (β_n) of the complexes as well partition ratios (P_n) of the extracted species were determined. It was shown that both β_n and P_n increased with an increasing 1-alkyl chain length. Tetrahedral complexes are more readily extractable by organic solvent. Their P_n values are the highest.     

烷基铝/氢化铝锂还原体系还原液体端羧基氟橡胶

采用两种还原体系二异丁基氢化铝（DIBAl-H）/氢化铝锂（LiAlH4）和三异丁基铝[Al（i-Bu）3]/LiAlH4,将液体端羧基氟橡胶（LTCFs）还原得到液体端羟基氟橡胶（LTHFs）。傅里叶转换红外光谱、核磁共振氢谱和核磁共振氟谱分析均表明,两种还原体系均能将LTCFs中的碳-碳双键和羧基分别还原成碳-碳单键和和羟基。进一步对比两种还原体系的还原能力发现,DIBAl-H/LiAlH4更适合还原LTCFs,且在反应温度为60 ℃、反应时间为8 h、羰基/LiAlH4/DIBAl-H物质的量比为1/1/2的最优条件下LTCFs的还原率可达到88%。与传统强还原剂LiAlH4相比,DIBAl-H/LiAlH4可降低反应温度,且减小还原剂用量。     

烷基苯磺酸钠／烷基二苯醚双磺酸盐复配体系的洗涤性能研究

主要考察了烷基苯磺酸钠（LAS）与十六烷基二苯醚双磺酸盐（D8390）复配体系在不同复配比、不同浓度、不同水硬度、不同温度条件下对不同种类污布的洗涤能力。结果表明：（1）对于碳黑、皮脂两种污布,单独D8390的洗涤能力不及LAs,LAS／D8390复配体系在w（LAS）：w（D8390）=8：2—7：3范围内洗涤能力最高;（2）对于蛋白污布,单独D8390的洗涤能力明显高于LAS,且在两者复配体系中,随着D8390含量的增加,洗涤能力先快速增大,在w（LAS）：W（D8390）=3：7时达到最高点,之后略降低。（3）在W（LAS）：W（D8390）=7：3的复配体系中,活性物总质量浓度在0．10％-0．20％范围内,质量浓度对碳黑、皮脂两种污布的洗涤能力影响不明显,但随着浓度的降低,对蛋白污布的洗涤能力明显降低;（4）采用LAS与D8390进行复配,可以明显改善体系在高硬度、低温下的洗涤能力。     

轮胎炼胶生产能源管理系统

研究烷基二硫代磷酸锌TPZ在丁苯橡胶（SBR）/白炭黑体系中的应用。结果表明：在SBR/白炭黑体系中以TPZ等量替代促进剂DPG,TPZ具有类似促进剂DPG的活化作用,可降低胶料的滚动阻力,且更加环保;少量TPZ作为偶联活化剂用于SBR/白炭黑体系的母炼中,可以减小硅烷偶联剂用量,降低成本,提高填料分散性和偶联效率,从而使胶料获得更佳的物理性能和动态力学性能。     

固定床催化合成烷基硫醇

介绍了固定床多相催化合成烷基硫醇的工艺流程。分析了以烷基醇与硫化氢为原料取代反应合成烷基硫醇可能发生的化学反应。采用固定床多相催化方法合成了多种烷基硫醇,其中正丙硫醇收率为92.5%、异丙硫醇收率达到65%、正丁基硫醇收率为76.6%、正十二烷基硫醇收率超过78%。介绍了合成以上烷基硫醇的反应温度、反应压力、原料进料配比等制备条件。     

Modulation of Muscarinic Signalling in the Central Nervous System by Steroid Hormones and Neurosteroids

Muscarinic acetylcholine receptors expressed in the central nervous system mediate various functions, including cognition, memory, or reward. Therefore, muscarinic receptors represent potential pharmacological targets for various diseases and conditions, such as Alzheimer’s disease, schizophrenia, addiction, epilepsy, or depression. Muscarinic receptors are allosterically modulated by neurosteroids and steroid hormones at physiologically relevant concentrations. In this review, we focus on the modulation of muscarinic receptors by neurosteroids and steroid hormones in the context of diseases and disorders of the central nervous system. Further, we propose the potential use of neuroactive steroids in the development of pharmacotherapeutics for these diseases and conditions.     

多聚磷酸法烷基磷酸酯的合成研究

用多聚磷酸与十六醇为原料制备出烷基磷酸酯。结果表明：当磷酸中五氧化二磷含量为７９９８％,十六醇与磷酸摩尔比为０９０,温度为７５℃的条件下反应６ｈ,单酯收率可达９３４％,酯总收率为９４５％。     

固体超强酸催化合成烷基磷酸酯

以月桂醇和磷酸为原料,采用固体超强酸催化制备烷基磷酸酯。探讨了催化剂用量、原料配比、反应时间和温度等因素对产品收率的影响。结果表明,最佳反应条件为:n(醇)∶n(酸)=2∶1,反应时间4 h,反应温度120℃,以甲苯共沸带水,催化剂用量为总物料质量的0.4%。     

烷基季铵盐改性膨润土的研究

考察了系列烷基季铵盐对膨润土有机化的效果和层间距变化,比较了两种钠化剂(Na2CO3和NaF)改性的膨润土对有机化的影响。实验结果表明,以NaF改性的膨润土获得了更佳的有机化效果和更大的层间距。在所考察的系列长链季铵盐有机化结果中,十八烷基二甲基苄基氯化铵(1827)和双十八烷基二甲基氯化铵(D1821)改性得到的层间距最大,分别为3 03nm和2 81nm。