Design,synthesis and insecticidal activity of novel analogues of flubendiamide containing alkoxyhexafluoroisopropyl groups

Flubendiamide has received considerable attention in the agriculture field due to its novel mode of action and excellent insecticidal activity. However, the high cost and toxicity to aquatic invertebrates associated with flubendiamide limit its agronomic utility. On the basis of the structure of the lead compound, flubendiamide, we designed and synthesized a series of novel analogues of flubendiamide bearing a alkoxyhexafluoroisopropyl moiety using 2-methyl-4-(2-alkoxyhexafluoroisopropyl) anilines as the key intermediates. Their insecticidal activities against the oriental armyworm (Mythimna separata Walker) were evaluated. The results indicated that most of the target compounds exhibited high insecticidal activities. Specifically, compound 8h showed the best insecticidal activity against the armyworm and its insecticidal activity reached 70% at 0.156 mg L⁻¹. The LC₅₀ value of compound 8h (0.0512 mg L⁻¹) is nearly the same as the corresponding commercial product flubendiamide (0.0412 mg L⁻¹). Furthermore, the acute toxicity test showed that the 48 h LC₅₀ values of compound 8h and flubendiamide against Daphnia magna Straus were 0.0066 and 0.0021 mg L⁻¹, respectively. The toxicity of compound 8h is obviously lower than flubendiamide.

A series of novel analogues of flubendiamide bearing alkoxyhexafluoroisopropyl moiety was synthesized. Their insecticidal activities against various insects were evaluated.     

Three-channel capillary NF membrane with PAMAM-MWCNT-embedded inner polyamide skin layer for heavy metals removal

Nanofiltration (NF) membranes with simultaneous high rejection of divalent cations and anions and high water permeation were designed and fabricated via interfacial polymerization (IP) on three-channel capillary ultrafiltration (UF) membranes. MWCNTs-COOH were modified with poly(amidoamine) (PAMAM) and the as-synthesized MWCNTs-PAMAM were embedded into the inner polyamide skin-layer of the NF membranes by incorporating them into a piperazine (PIP) aqueous solution, followed by IP with trimesoyl chloride (TMC). The rigid MWCNTs and the dendrimer PAMAM molecules endow the as-fabricated NF membranes with high porosity and good hydrophilicity. Additionally, the –NH₂ groups of PAMAM introduce some positive sites into the polyamide layer. The as-prepared NF membranes with incorporated MWCNTs-PAMAM exhibit a pure water flux of 48.7 L m⁻² h⁻¹ and 92.6% and 88.5% rejection for Na₂SO₄ and MgCl₂, respectively, at 4 bar. Moreover, the NF membranes display high rejection for sulfates and metal cations, including heavy metal ions. The practicability of the membranes for mine-wastewater treatment was tested, and the membranes showed above 80% rejection of heavy metals and solution flux of about 30 L m⁻² h⁻¹. In addition, their separation performance and stability were satisfactory during the long-term run. The high rejection of the membranes for metal cations is ascribed to the positive sites offered by MWCNTs-PAMAM and the narrow membrane pores since both electrostatic repulsion and size exclusion play a role during membrane filtration. The good separation performance of the membranes for multivalent anions and heavy metal cations illustrates their potential for applications in heavy metal wastewater treatment.

MWCNTs-PAMAM were incorporated into the polyamide layer of NF membranes and the prepared membranes showed good permeation and rejection performances.     

Ligand geometry controlling Zn-MOF partial structures for their catalytic performance in Knoevenagel condensation

A series of novel Zn-MOFs {1Zn: [Zn(NIA)₂(3-bpdh)₂]; 2Zn: [Zn(NPA)₂(4-bpdh)₂H₂O]; 3Zn: [Zn₂(CHDA)₄(3-bpd)₂]} were constructed by dicarboxylic acid and N,N′-bis(pyridine-yl-ethylidene)hydrazine. Ligand geometry revealed 1D to 3D Zn-MOF crystal topologies, whose combined-mode could be affected by the conditions. All these conditions affected the micro-nano crystal morphologies, namely 1Zn micro-sheets or nanospheres, 2Zn micro-clusters or micro-stick, and 3Zn micro-clusters or hollowspheres that were obtained. The catalysts exhibited 100% selectivity for Knoevenagel condensation reactions, among which the benzaldehyde conversion rate of the 3Zn hollowspheres was the highest, reaching a peak of 90%.

Novel 1D to 3D structures of Zn-MOFs and their morphologies were assembled and showed high catalytic performance for Knoevenagel condensation.

Metal–organic frameworks (MOFs) are a kind of rigid skeletal crystal formed via the coordination of metal ions with organic ligands, characterized by a large specific surface area, high porosity and structural diversity.^1–3 The abundance of metal atoms and organic ligands led to diverse and intriguing assemblies.⁴ Since the pioneering work of Yaghi et al.^5–7, more than 20 000 MOFs have been reported and have shown remarkable prospects in many applications, such as adsorption,^8–11 electrochemistry,^12–14 catalysis^15–17 and luminescence,^18–20 among which the research on catalysis is one of the rapidly growing applications. The inherent properties of MOFs make them excellent catalysts: these properties include highly dense active sites and even dispersion in the skeletons of MOFs, while their porosity facilitates the transport and diffusion of reactants, facilitating easy contact with those active sites.²¹The Knoevenagel condensation is a classic reaction, which provides an effective way to form C–C double bonds by the reaction of carbonyl compounds, such as aldehydes or ketones, with compounds containing active methylene groups. It has been widely used in the synthesis of many compounds and is a reaction with an important application value in organic synthesis.^22–26 In recent years, many catalysts for such reactions have emerged,^27–29 among which MOFs or MOF-derived solid bases have shown remarkable catalytic performance.^30–33In this study, we prepared three new MOFs with one-dimensional, two-dimensional and three-dimensional structures. First, by combining zinc 5-nitroisophthalic acid (NIA) with N,N′-bis(1-pyridine-3-yl-ethylidene)hydrazine (3-bpdh) (1Zn); second, by combining zinc 3-nitrophthalic acid (NPA) with N,N′-bis(1-pyridine-4-yl-ethylidene)hydrazine (4-bpdh) (2Zn); and third, by combining zinc 1,4-cyclohexanedicarboxylic acid (CHDA) with N,N′-bis(1-pyridine-3-yl-ethylidene) (3-bpd) (3Zn). By changing the reaction conditions, 1Zn nanospheres, 2Zn microsticks and 3Zn hollowspheres were obtained. We also investigated the catalytic performance of the six catalysts for Knoevenagel condensation and analyzed the possible catalytic mechanism.As shown in Fig. 1, the zinc atoms in all three crystals are present in a hexacoordinate environment; however, the coordination direction can be influenced by different ligands coordinated with zinc atoms, so as to obtain three kinds of MOFs with one-dimensional, two-dimensional and three-dimensional structures. 1Zn crystallized in a triclinic space group P$\bar{1}$(2) [a = 8.585(5) Å, b = 10.181(6) Å, c = 14.860(12) Å, α = 104.46(9)°, β = 101.00(9)°, γ = 102.35(6)°, V = 1186.92(140) ų, Z = 2]. The Zn(ii) center was bonded to four O atoms from the carboxylate groups of two 5-nitrophthalic acid ligands and two N atoms from the 3-bpdh ligand, forming ZnO₄N₂ metal nodes. Two 3-bpdh ligands linked two ZnO₄N₂ metal nodes to form ring structures, and each ring was connected by 5-nitrophthalic acid molecules. The single coordination direction determines the one-dimensional (1D) tube structure of the crystal. 2Zn crystallized in a monoclinic space group P12₁/c₁(14) [a = 14.74(3) Å, b = 8.444(15) Å, c = 19.15(3) Å, β = 106.96(17)°, V = 2279.87(700) ų, Z = 4]. The Zn(ii) center was bonded to three O atoms from the carboxylate groups of two 3-nitrophthalic acid ligands, two N atoms from the 4-bpdh ligand, and one O atom from H₂O, forming ZnO₄N₂ metal nodes. In this metal node, the carboxyl group had two coordination modes: the O atoms from No.1 and No.2 carboxyls in one 3-nitrophthalic acid chelated the Zn(ii) center to form 7-member ring, while the O atom from the No.1 carboxyl in the other 3-nitrophthalic acid bridged this Zn(ii) center to other ZnO₄N₂ metal nodes. The 4-bpdh ligand and 3-nitrophthalic acid ligands formed a double chain with a ZnO₄N₂ metal node as the center. The coordination method of 2Zn is limited to a two-dimensional (2D) plane, resulting in its 2D structure. 3Zn crystallized in a monoclinic space group C₁2/c₁(15) [a = 17.23(3) Å, b = 19.96(3) Å, c = 9.432(15) Å, β = 105.71(18)°, V = 3122.62(800) ų, Z = 8]. Two Zn(ii) centers were bonded to eight O atoms from the carboxylate groups of four 1,4-cyclohexanedicarboxylic acid (CHDA) ligands and two N atoms from the 3-bpd ligand, forming Zn₂O₄N₂ metal nodes. Four CHDA ligands formed a cross double chain with two zinc atoms as the center, and the 3-bpd ligand linked the double chains to yield a three-dimensional (3D) framework. More detailed information about the crystal structure is contained in the ESI.^†Open in a separate windowFig. 1Molecular structure of 1Zn, 2Zn, 3Zn.These three kinds of microcrystals were prepared in methanol and water at room temperature. As shown in Fig. 2, the three kinds of MOFs have different morphologies. Under SEM, 1Zn presents a sheet structure, while 2Zn and 3Zn show flower-like morphologies, which are formed by the secondary assembly of tiny crystals. They are about 10 to 20 microns in diameter, and 3Zn is slightly larger than 2Zn. The PXRD patterns of the three crystals coincide with the simulated curves of their single crystal, which proves the existence of the respective crystal phases (Fig. S1–S3^†).Open in a separate windowFig. 2SEM images of (a–c) 1Zn; (d–f) 2Zn; (g–i) 3Zn.On this basis, we used different conditions to change the morphologies of these three crystals, which exhibited three improved morphologies (Fig. 3). More conditions were attempted, and the results are shown in the ESI.^† A 1Zn nanosphere was synthesized in a DMF system with the introduction of PVP by a solvent thermal method. PVP is an amphiphilic surfactant, which can adsorb on the surface of nanocrystals and change the growth direction and speed of the crystals, thus affecting the final morphology and particle size of the product.³⁴ With the increase in the PVP dosage, the size of the 1Zn nanosphere was smaller and more uniform (Fig. S10^†). At 0.1 g PVP dosage, nanospheres with particle sizes of about 300 nm were obtained. A 2Zn microstick was also synthesized by the solvent thermal method in MeOH solvent. Interestingly, we added sodium acetate as a regulator to the DMF system and obtained 3Zn hollowspheres with the assistance of ultrasound. When the dosage of sodium acetate was 0.05 mmol, a dandelion-like 3Zn spherical crystal reassembled by needle crystals was obtained. On continuously increasing the amount of sodium acetate to 0.1 mmol, the spherical crystals became hollow. However, when sodium acetate was added to 0.2 mmol, the morphology of the product appeared chaotic (Fig. S11^†). As a base, sodium acetate can accelerate the deprotonation process of carboxylic acid ligands, thus accelerating the growth rate of the crystals. Moreover, there was competitive coordination between COO⁻ and the carboxylic acid ligands, so the introduction of sodium acetate can affect the growth process of the crystals.³⁵Open in a separate windowFig. 3SEM images of (a–c) 1Zn (DMF, 100 °C, 0.1 g PVP); (d–f) 2Zn (MeOH, 120 °C); (g–i) 3Zn (0.1 mmol NaAC, 0.5 h of ultrasonic treatment, standing at room temperature for 24 h).The catalytic properties of the catalysts for the Knoevenagel condensation reactions were investigated. As shown in Fig. 4, when the 1Zn and 2Zn microcrystals were used as catalysts, the conversions are 64% and 76% after 4 hours reaction, respectively, but 3Zn could reach more than 88%. After controlling the morphology, the order of catalytic performance was still 1Zn < 2Zn < 3Zn, which may be related to the structure of the MOFs. 3Zn with its 3D coordination structure may be more conducive to providing a smooth path for the rapid transfer of electrons.Open in a separate windowFig. 4The catalysts and their conversion in Knoevengal condensation reaction.Moreover, after adjusting the morphology, the catalytic effects of 1Zn, 2Zn, 3Zn were improved. The conversion of benzaldehyde was increased to 86% for the 1Zn nanosphere, 87% for the 2Zn microstick and 90% for the 3Zn hollowsphere (Fig. S13^†). The catalytic activity of all the Zn-MOFs may be related to the size, dispersion and accessible surface areas of the catalyst.³⁶ For contrast, we studied the Knoevenagel condensation reaction with n-heptanal, keeping other conditions unchanged. The results are shown in the ESI (Fig. S14^†). It was found that the results obtained with benzaldehyde or heptanal were similar in general; after adjusting the morphology, the conversion of heptanal catalyzed by the 1Zn nanosphere, the 2Zn microstick and the 3Zn hollowsphere were still higher than those of their microcrystals. The catalytic efficiency of the 1Zn nanosphere reached 90%, while that of the 3Zn hollowsphere was 85%, close to that of the 3Zn micro-cluster. On this basis, we performed the BET analysis of the 3Zn micro-cluster and 3Zn hollowsphere, and the results presented in the ESI (Fig. S12^†) show that the median pore width of the 3Zn micro-cluster and 3Zn hollowsphere are similar. The BET surface area of the micro-cluster is larger than that of the hollowsphere, but the volume of the pores is smaller than that of the hollowsphere. So, we suppose that because of the similar pore width, the key to improving the conversion of benzaldehyde is the pore volume. However, in comparison, heptanal is bulky and cannot enter the pore as easily as benzaldehyde, so the catalytic efficiency of the 3Zn hollowsphere is close to that of the 3Zn micro-cluster.^31,37,38 The XRD patterns of all the catalysts after catalysis were consistent with those before catalysis (Fig. S4–S9^†), indicating that the structure did not change.There are two main mechanisms of Knoevenagel condensation catalyzed by MOFs: basic catalysis and bifunctional acid–base catalysis.³⁹ In our study, the three Zn-MOFs seemed to prefer the acid-catalyzed mechanism since they did not have a strong basic group, such as the amino group; although the ligand contains two N atoms, these two N atoms already have three bonds, the electron cloud is dispersed, and the –NO₂ and –COOH groups on the organic carboxylic acid ligands also weaken the basicity. Based on other studies,^36,40,41 we proposed a possible bifunctional acid–base catalytic mechanism. The Zn(ii) in the Zn-MOF has empty atomic orbitals, which can be used as the Lewis acid sites. The carbonyl oxygen carries a pair of lone pair electrons that coordinate with Zn(ii), so the positive charge on the O atom can promote further polarization of the carbonyl group. The positive electricity of the carbonyl C atom can thereby be enhanced. At the same time, the hydroxyl O atom coordinated with the Zn(ii) ion acted as the center of the Lewis basic sites, which promoted the active methylene of malonitrile to remove protons and formed a carbon anion near benzaldehyde. Then, malonitrile attacked the carbonyl C atom of benzaldehyde, and the intermediate became the product and regenerated the catalyst after rearrangement and dehydration (Fig. 5).Open in a separate windowFig. 5The scheme catalytic mechanism of Knoevengal condensation reaction.     

降解海藻酸钠磺化衍生物选择清除血浆LDL/Fib的性能研究

以海藻酸钠为原料,进行氧化降解,再以氯磺酸为磺化试剂,在适当的条件下进行磺化反应,获得降解海藻酸钠磺化衍生物(degraded sodium alginate sulfate,DSAS)。考察不同磺化条件对硫酸基含量的影响,通过正交实验确立较优磺化反应条件。红外光谱分析表明,该衍生物为酸性粘多糖。以降解海藻酸钠磺化衍生物为净化剂,研究其选择清除血浆低密度脂蛋白(LDL)及纤维蛋白原(Fib)的性能。结果表明,在pH=5.15,净化剂浓度2 500mg/L时,可使血浆总胆固醇下降60%左右,低密度脂蛋白和极低密度脂蛋白下降80%左右,纤维蛋白原下降接近100%,而对高密度脂蛋白及血浆总蛋白水平无显著变化。     

需求量不确定条件下连续过程生产调度

研究了需求量不确定条件下连续工业生产过程的生产调度问题，并考虑了定单的交货期窗约束，采用三角模糊数描述不确定性，建立了需求量不确定条件下的模糊调度数学模型，并给出了基于遗传算法的优化方法，仿真试验验证了方法的有效性。     

负载型丝光沸石催化剂的催化性能研究

运用二元碱氮置换吸附红外光谱法、分子筛孔径分布测定技术、XPS技术,考察了丝光沸石表面酸性与孔结构的相互关系、钯在丝光沸石上分布情况和价态及其与沸石的相互作用。结果表明,随着丝光沸石脱铝程度的增加,表面出现大量不规整晶格,存在较多的次级孔道。强质子酸中心主要分布在它的“外表面”。钯在其表面富集,并与“外表面”上的质子酸中心协同作用,促进了轻质烷烃异构化反应。     

胰酶水解干酪素的动力学行为

研究了胰酶水解干酪素制备蛋白胨过程中胰酶在不同温度下的失活行为,以及底物浓度对反应速率和平衡的影响,ｐＨ对反应浓度和平衡的影响。胰酶在４０℃下４ｈ基本不丧失水解大分子的活力;在５０℃,ｍｉｎ、５５℃,１００ｍｉｎ、６０℃,９０ｍｉｎ完全丧失对大分子的水解活性。胰酶短时间在高温下丧失的活性,当其返回到４０℃时可部分恢复。底物和产物对反应有抑制作用。底物初始浓度高,最终平衡转化率低。当ｐＨ８时的反应速     

杂合启动子控制下乙肝病毒表面抗原SA—28融合基因在酵母中？…

在杂合启动子ＡＤＨ２－ＧＡＰＤＨ控制下于酿酒酵母中表达乙肝病毒表面抗原ＳＡ－２８融合基因的过程研究中,确定系统表达的有效阻遏条件为在１０．０ｇ／Ｌ的葡萄糖浓度下进行细胞的预培养,采用稀释操作和碳源饥饿培养等较彻底的支阻遏方式以克服葡萄糖酵解产物阻遏对表达的影响。实验还显示了溶解氧浓度对表达的影响和乙醇流加方式对表达期酵母生长与表达的调节作用。实验获得主培养４５ｈ后湿菌体浓度为１８６ｇ／Ｌ,细胞内ｐ     

高温煤气中HC1气体与脱氯剂的反应动力学

在固定床反应器中研究了自制的脱氯剂与高温煤气中ＨＣ１气体的反应动力学,得出在５５０℃时反应受通过产物层的扩散和化学反应反控制,两埂的阻力之比为０．１３８。同时研究了温度和进口ＨＣ１气体浓度对该反应影响,得出反应对于气相ＨＣ１为一级反应。     

供氧对红霉素基因工程菌ZL1004发酵液组分的影响

本文研究了供氧条件对红霉素基因工程菌ZL1004发酵液组分的影响。摇瓶条件下考察了不同形式的摇床和摇瓶装液量对发酵液组分的影响,发现供氧能力好的双层敞开旋转摇床有利于组分改善,发酵终点时发酵液中有效组分A为93．93％,副产物B为4．59％,C为1．48％;500ml摇瓶装液量最少时（35ml）发酵液组分最好（A组分为92．13％,B组分为1．73％,C组分为6．14％）。进一步在50L发酵罐中的研究表明,高溶氧（全程溶氧高于40％）时B组分含量一直为0％,与低溶氧（全程溶氧低于40％）相比,发酵液中A组分提高13．51％,C组分降低71．3％。研究结果说明对于红霉素基因工程菌ZL1004,发酵过程较好的供氧条件是提高发酵液有效组分的重要条件。