复分解电渗析清洁生产谷氨酸钠新工艺

谷氨酸钠（sodium glutamate,NaGA）是味精（monosodium glutamate,MSG）的主要成分,其传统生产方法为"等电点结晶-酸碱中和"法,传统工艺存在工艺流程长、酸碱消耗大、环境污染严重等问题,而且其谷氨酸钠产品液浓度尚未达到结晶工艺所需的浓度。为此本文提出复分解电渗析离子重组工艺来清洁生产谷氨酸钠,并对该工艺进行了实验验证及过程优化。复分解电渗析可实现原料液的一步转化,直接获得高浓度谷氨酸钠产品液,在优化条件下,最终产品液浓度为1.79mol/L （约30.2%）,转化率为91.2%,能耗为2.98kW·h/kgNaGA,其副产（NH₄）₂SO₄可作为生产铵肥的原料,不存在二次污染。此工艺具有工艺流程短、酸碱零消耗、无二次污染的优点,而且所得谷氨酸钠产品液浓度达到了结晶工艺所需的浓度要求,这对电驱动膜过程在味精产业的应用具有重要意义。并通过对树脂填充床电渗析与普通电渗析、均相离子交换膜与异相离子交换膜的比较实验,验证了选用异相膜树脂填充床电渗析生产谷氨酸钠的合理性。     

Well‐Defined End‐Functionalized Conjugated Polymers/Oligomers Exhibiting Unique Emission Properties through the End Groups: The Exclusive Synthesis by Combined Olefin Metathesis with Wittig‐type Coupling

Acyclic diene metathesis polymerization using ruthenium–carbene catalysts affords defect‐free, high molecular weight poly(arylene vinylene)s containing all trans olefinic double bonds. The exclusive end‐functionalization in the resultant poly(fluorene vinylene)s or poly(phenylene vinylene)s can be attained by treating the vinyl end groups using a molybdenum–alkylidene catalyst/reagent (through olefin metathesis) followed by addition of various aldehydes (Wittig‐type coupling). Some of these end‐modified conjugated materials display unique emission properties, which are different from the original ones, through an interaction (energy transfer or structural change in the excited state) between the conjugated main chain and the end groups [oligo(thiophene)s, F‐BODIPY, etc.]. Exclusive synthesis of well‐defined, all‐trans end‐functionalized oligo(2,5‐dialkoxy‐1,4‐phenylene vinylene)s [(oligo(phenylene vinylene), alkoxy = O(CH₂)₂OSiⁱ Pr₃, up to 31 repeat units] is demonstrated by adopting a stepwise synthetic approach (olefin metathesis and the subsequent Wittig‐type cleavage). It is clearly demonstrated that their optical properties (especially the fluorescence spectra including photoluminescence quantum yields) are strongly affected by the end groups as well as the conjugation repeat units.     

Photoelectrochemical solar cell fabrication with tungsten diselenide single crystals

Recent reports on highly efficient photoelectrochemical solar cells withn-type WSe₂ have prompted us to grown-type single crystals of WSe₂ using a chemical vapour transport method. Different transporting agents have been used. It is seen that SeCl₄ transporter leads to very large single crystals ofp-type WSe₂, whereas the same transporting agent with excess amount of Se leads ton-type single crystals. PEC solar cells fabricated withp-type andn-type crystals thus grown have been reported and the results discussed.     

Large-Scale,Controllable Synthesis of Ultrathin Platinum Diselenide Ribbons for Efficient Electrocatalytic Hydrogen Evolution

2D platinum diselenide (PtSe₂) exhibits exceptional layer-dependent electrical properties and high catalytic activity for hydrogen evolution reactions, making it an ideal system for studying structure–activity correlations. However, the synthesis of high-quality atomically thin PtSe₂ materials has proven challenging. This study presents a simple chemical vapor deposition method for synthesizing high-quality ultrathin 1T-PtSe₂ ribbons on Au foils, making it easily applicable. Theoretical and experimental results confirm that these atomically thin 1T-PtSe₂ ribbons possess abundant catalytic sites and can serve as ideal electrocatalysts. This study advances the large-scale synthesis and potential application of ultrathin transition metal disulfides and presents a novel method for designing and synthesizing highly active ultrathin catalysts.     

增产基本有机原料的新途径

从炼化一体化、增产丙烯技术、开发以烷烃为原料以及c。烃类化工技术等方面综述了增产基本有机原料的新途径,并对这些技术作了经济分析。认为近期应采取炼厂与石化厂一体化、烯烃歧化、C4～C8烯烃催化裂解等措施,从而增加我国烯烃和芳烃产量;从长远发展看,应开发基于C1烃类及含氧化合物各种工艺技术和生物催化技术等,以满足我国未来基本有机原料的市场需求。     

Palladium‐Catalyzed Decarbonylative Dehydration of Fatty Acids for the Production of Linear Alpha Olefins

A highly efficient palladium‐catalyzed decarbonylative dehydration reaction of carboxylic acids is reported. This method transforms abundant and renewable even‐numbered natural fatty acids into valuable and expensive odd‐numbered alpha olefins. Additionally, the chemistry displays a high functional group tolerance. The process employs a low loading of palladium catalyst and proceeds under solvent‐free and relatively mild conditions.

     

聚合物合成反应的新进展

扼要阐述了传统聚合反应的进展,简要评述了环烯烃开环置换聚合、基团转移聚合、变换聚合反应以及端活性齐聚物的合成。     

Aphrodisiac Pheromones from the Wings of the Small Cabbage White and Large Cabbage White Butterflies,Pieris rapae and Pieris brassicae

Pheromonally yours : The aphrodisiac pheromones of male Cabbage White butterflies were identified. The small butterfly uses the smaller molecule ferrulactone ( 1 ) to enhance its mating success, while the large butterfly uses the larger compound brassicalactone ( 2 ), which is a new natural product. Both compounds are active in combination with hexahydrofarnesylacetone and phytol.

     

New Indenylidene‐Schiff Base‐Ruthenium Complexes for Cross‐Metathesis and Ring‐Closing Metathesis

We here report on the stability and catalytic activity of new indenylidene‐Schiff base‐ruthenium complexes 3a – f through representative cross‐metathesis (CM) and ring‐closing metathesis (RCM) reactions. Excellent activity of the new complexes was found for the two selected RCM reactions; prominent conversion was obtained compared to the commercial Hoveyda–Grubbs catalyst 2 . Moreover, excellent results were obtained for a standard CM reaction. Higher conversions were achieved with one of the indenylidene catalysts compared with Hoveyda–Grubbs catalyst. Unexpectedly, an isomerization reaction was observed during the CM reaction of allylbenzene. To the best of our knowledge, isomerization reactions in this model CM reaction in closed systems have never been described using first generation catalysts, including the Hoveyda–Grubbs catalyst. The first model CM reactions as well as the RCM reactions have been monitored using ¹H NMR. The course of the CM reaction of 3‐phenylprop‐1‐ene ( 8 ) and cis‐1,4‐diacetoxybut‐2‐ene ( 9 ) was monitored by GC. The isomerization reaction was studied by means of GC‐mass spectrometry and in situ IR spectroscopy. All catalysts were structurally characterized by means of ¹H, ¹³C, and ³¹P NMR spectroscopy.     

Room temperature transport measurements on Bridgman-grown p-type CuIn1−xGaxSe2

Room temperature measurements were made of electrical conductivity (σ), Hall coefficient (R_H) and Seebeck coefficient (α) on filamentary samples of p-type CuInSe₂ and CuIn_1−xGa_xSe₂ with x0.3, cut from vertically grown Bridgman ingots. Analysis of the results was done on a two-carrier basis, due to the higher ratio of electron to hole mobility (b) in these materials compared to elemental semiconductors. This treatment yielded a preferred b-value of 5 and to lower calculated hole concentrations than (R_He)⁻¹ and higher hole mobilities than R_Hσ, based on a one-carrier interpretation. This effect was particularly marked in p-type samples with a hole concentration below 10¹⁷ cm⁻³, where even a few percent of minority electrons can play an important role.