从叔醇制备叔硫醇

实验室中合成叔硫醇缺少简便方法。用叔醇和氢溴酸与硫脲直接反应是目前采用的方法。Lee和Akerstrom曾用此法合成了叔硫醇,但碳原子数没超过七个。Sprague及Kresze分别用干燥氯化氢及盐酸代替氢溴酸也合成了叔硫醇,但产率不高。本文提出了用叔醇、硫酸与硫脲反应来制备叔硫醇的方法,并合成了六个叔硫醇。     

Control of Vicinal Stereocenters through Nickel-Catalyzed Alkyl–Alkyl Cross-Coupling

Vicinal stereocenters are found in many natural and unnatural compounds. Although metal-catalyzed cross-coupling reactions of unactivated alkyl electrophiles are emerging as a powerful tool in organic synthesis, there have been virtually no reports of processes that generate, much less control, vicinal stereocenters. In this investigation, we establish that a chiral nickel catalyst can mediate doubly stereoconvergent alkyl–alkyl cross-coupling, specifically, reactions of a racemic pyrrolidine-derived nucleophile with cyclic alkyl halides (as mixtures of stereoisomers) to produce vicinal stereocenters with very good stereoselectivity.     

烷基多苷的分析测定

ＧＣ、＾１Ｈ－ＮＭＲ和＾１３Ｃ－ＮＭＲ核磁共振技术都能准确地测量出烷基多苷的平均聚合度,可判断出烷基多苷中主要苷类的出峰位置。     

Copper-Catalyzed Coupling Reaction of Secondary Alkyl 2-Pyridinesulfonates with Alkyl Lithium-Based Reagents

The Cu(OTf)₂-catalyzed alkyl–alkyl coupling reaction of a secondary substrate MeCH(OSO₂Py)CH₂CH₂C₆H₄(4-OMe) with a nBuLi-based reagent prepared by transmetalation with MgBr₂ ⋅ THF₃ in THF produced a coupling product in 74 % yield. The use of soluble MgBr₂ ⋅ THF₃ in THF was required for this reaction. This method was applied to sBuLi and Ph(CH₂)₄Li. In contrast, transmetalation of MeLi with soluble MgCl₂ ⋅ THF₂ in THF produced the Me reagent, which was reactive for the coupling reaction. The reaction proceeded with inversion of the stereogenic carbon. Furthermore, (S)-14-methyloctadecan-2-one, a sex pheromone produced by lichen moths, was synthesized.     

短链烷基对多取代烷基苯磺酸盐界面性质的影响

利用悬挂滴方法研究了2,5-二乙基-4-壬基苯磺酸钠(292)、2,5-二丙基-4-壬基苯磺酸钠(393)和2,5-二丁基-4-壬基苯磺酸钠(494)在空气-水表面和正癸烷-水界面的扩张流变性质,考察了时间、界面压、工作频率及体相浓度对扩张弹性和粘性的影响。研究发现,在低表面活性剂浓度条件下,表面吸附膜类似弹性膜,其强度由膜内分子的相互作用决定;高浓度下体相与表面间的扩散交换过程控制表面膜的性质。油分子的插入导致界面吸附分子之间相互作用的削弱,扩散交换过程主导界面膜性质;但随着短链烷基长度增加,油分子的影响变小。表面膜的强度在吸附达到平衡前已经决定,而界面膜在吸附饱和后仍然随界面分子重排而变化。     

乳酸酯氧化脱氢制备丙酮酸酯的研究进展

生物质资源替代化石资源制取燃料和化学品已成为发展可再生能源化工的重要研究方向之一。本文综述了近年来以生物质平台分子乳酸酯为原料制备丙酮酸酯的研究工作,主要涉及的反应包括气相催化反应、液相催化反应和光催化反应。详细讨论了各种类型的催化剂对反应性能的影响;最后,对乳酸酯催化转化制取丙酮酸酯的发展前景进行了展望。     

Polymerization of Diallyl Alkyl Isocyanurates

Abstract

Polymerizations of several diallyl alkyl isocyanurates were investigated to explore in more detail the steric effect observed in the polymerization of triallyl isocyanurate [3, 5], as compared to its isomer triallyl cyanurate, by changing alkyl groups from methyl, propyl, hexyl, and octyl up to lauryl. The rate of polymerization, the gel point, the cyclization constant, and the primary chain length were evaluated. For example, the primary chain length increased with an increase in the bulkiness of the alkyl group as expected, although in the polymerization of diallyl lauryl isocyanurate it decreased as a reflection of reduced rate of propagation due to the enhanced steric effect arising from a very bulky lauryl group.     

电喷雾质谱法对重烷基苯的族组成分析与结构鉴定

建立了一种系统的分析重烷基苯的方法。通过柱色谱对重烷基苯进行了分离，将其分成了六个族组分，对这六个族组分进行红外、紫外以及荧光鉴定，确定了各族组分的归属，利用电喷雾质谱测定了第二到第五族组分磺酸盐的相对分子量分布，结合红外、紫外所测定的结果，及每族物质的不饱和度和通式，推算出了烷基芳烃部分的相对分子质量和烷基苯的碳数分布。     

Effect of Alkyl Chain Length on the Interfacial Dilational Properties of Hydroxy-Substituted Alkyl Benzenesulfonates

Dilational rheological behaviors of adsorption layers of three surfactants, sodium 2-hydroxy-3,5-dioctyl benzene sulfonate (C₈C₈), sodium 2-hydroxy-3-octyl-5-decyl benzene sulfonate (C₈C₁₀), and sodium 2-hydroxy-3-octyl-5-dodecylbenzenesulfonate (C₈C₁₂) formed at air–water and decane–water interfaces, have been investigated as a function of concentration and frequency (0.002–0.1 Hz) by the oscillating bubble/drop method. The experimental results show that the dilational moduli of hydroxy-substituted alkyl benzenesulfonates are obviously higher than those of the common surfactants, because the interfacial interactions between alkyl chains are improved drastically by the unique arrangement of C₈C₈ molecules at the interface. However, the moduli at the decane–water interface are much lower than those at the surfaces because decane molecules will insert into the surfactant molecules adsorbed at the interface and destroy the interactions between alkyl chains. With an increase in the number of carbon atom of 5-alkyl, the surface dilational modulus decreases because the orientation of the surfactant molecules at the surface varies from parallel to tilt. On the other hand, the diffusion-exchange process dominates the interfacial behavior and the interfacial modulus improves with the increase in the length of the alkyl chain.     

二烷氧基膦酰乙酸酯的核磁共振

许多有机磷化合物的核磁共振已有报道。本文研究二烷氧基膦酰乙酸酯化合物(?)(1～17)的~1H、~(31)P 及~(13)CNMR 谱,观察了 P—O—C 键的受阻转动,获得了~2J_(CCP),~3J_(CCOP)和 J_(HP)值。对鉴定其它磷化物的结构有一定意义。化合物1,3虽有同核二     

Qualitative Chromatographic–Mass Spectrometric Analysis of Highly Toxic Alkyl Phosphonate and Alkyl Thiophosphonate Derivatives

The main goal of chemical analytical monitoring in the destruction of chemical weapons is to identify highly toxic compounds of similar structures in long homologues series. The difficulties with the identification are due to a wide range of possible structures of such compounds with similar mass-spectral patterns. This necessitates the development of special approaches to the interpretation of analytical data. The paper presents the data of experimental studies of specific features of chromatographic–mass spectrometric behavior of 150 substances of the specified classes. The account of these data can improve the reliability of the identification.     

Alkyl polyglucoside microemulsion phase behavior

We review several key elements of alkyl polyglucoside (C_mG_n) microemulsion phase behavior. The low solubility of C_mG_n surfactants in oils such as alkanes makes producing C_mG_n microemulsions and subsequent study of their phase behavior difficult. Increasing the solubility of C_mG_n in oil is therefore helpful for the systematic study of C_mG_n-based microemulsion formulations. To this end, the role of cosurfactants in producing microemulsions with water, alkanes, and n-alkyl β-d-glucopyranosides is first discussed. Adding C₁₀βG₁ to mixtures of water–alkane–ethoxylated alcohol surfactants (C_iE_j) produces a region of the three-phase body (a ‘chimney’) that is independent of temperature; thus C_mβG₁ are not completely soluble in the co-oil formed of alkane and C_iE_j at higher temperatures. Then, through a novel approach using oxygenated ether oils (C_kOC₂OC_k), microemulsions are formed with water, C_kOC₂OC_k, and C_mβG₁ and the phase behavior studied as a function of temperature and composition. Increased C_mβG₁ solubility in the more hydrophilic ether oils produces patterns of phase behavior in water–C_kOC₂OC_k–C_mβG₁ mixtures that are identical to those observed in water–alkane–C_iE_j mixtures. Using the water–ether oil–C_mβG₁ mixtures as a base case, the role of C_mG_n surfactant structure in setting C_mG_n microemulsion phase behavior is explored. The solubility of the α-d anomer (n-alkyl α-d-glucopyranosides, C_mαG₁) in water is much less than that of the β-d surfactant, and these solubility boundaries extend to high surfactant and oil concentrations in water–C_kOC₂OC_k–C_mαG₁ mixtures. Adding C_mG₂ compounds to water–C_kOC₂OC_k–C_mβG₁ mixtures shifts the phase behavior to high temperatures, again demonstrating the extreme hydrophilic nature of the sugar headgroup. Finally, adding small amounts of ionic alkyl sulfate surfactants to water–C_kOC₂OC_k–C_mβG₁ mixtures dramatically reduces the total amount of surfactant needed to form a single-phase microemulsion.     

Spontaneous Emulsification of Alkyl Ketene Dimer

A screening method using factorial design has been used to arrive at a workable formulation for self-emulsification of alkyl ketene dimer, AKD. The emulsification was performed at 60°C which is above the melting temperature of the AKD. Good results were obtained with a combination of calcium dodecylbenzene sulphonate and an alcohol ethoxylate as surfactants and a small amount of dodecanol as cosurfactant. The three amphiphilic compounds were dissolved in the AKD and the mixture was added to the aqueous phase under gentle stirring. The mechanism behind the easy formation of the AKD-in-water emulsion is discussed.     

Iron‐Catalyzed Decarboxylative Alkyl Etherification of Vinylarenes with Aliphatic Acids as the Alkyl Source

Because of the lack of effective alkylating reagents, alkyl etherification of olefins with general alkyl groups has not been previously reported. In this work, a variety of alkyl diacyl peroxides and peresters generated from aliphatic acids have been found to enable the first iron‐catalyzed alkyl etherification of olefins with general alkyl groups. Primary, secondary and tertiary aliphatic acids are suitable for this reaction, delivering products with yields up to 97 %. Primary and secondary alcohols react well, affording products in up to 91 % yield.