4,4′-二(β-萘氧基)二苯砜改性聚醚酮醚酮酮的研究

将新单体－４，４′－二（β－萘氧基）二苯砜（ＢＮＯＤＰＳ）和对苯二甲酰氯、４，４′－二苯氧基二苯甲酮进行傅－克酰化聚合，制得了一系列主链含萘环的聚醚酮醚酮酮／聚醚砜醚酮酮（ＰＥＫＥＫＫ／ＰＥＳＥＫＫ）共聚物。研究表明，ＰＥＳＥＫＫ含量小于４０ｍｏｌ％时，可制得结晶聚合物。共聚物具有比ＰＥＫＥＫＫ更优异的耐热性，随着主链中ＰＥＳＥＫＫ含量增加，共聚物Ｔｇ逐渐升高，Ｔｍ、结晶度逐渐降低，仍具有很好的耐溶剂性。     

亲电聚合法合成甲基取代聚芳醚酮酮的研究

由间甲基二苯醚（ＭＰＥ）和对苯二甲酰氯（ＴＰＣ）、间苯二甲酰氯（ＩＰＣ）、２,５－二氯对苯二甲酰氯（ＤＣＣ）等芳二酰氯在１,２－二氯乙烷（ＤＣＥ）中,以无水ＡｌＣｌ３为催化剂,在Ｎ－甲基吡咯烷酮（ＮＭＰ）存在下,进行亲电缩聚反应,合成了五种不同结构的甲基取代的聚醚酮酮（ＭｅＰＥＫＫ）。用ＩＲ、ＤＳＣ和ＷＡＸＤ等方法对聚合物进行了分析表征,结果表明：聚合物的对数比浓粘度在０．５～０．６８ｄＬ／ｇ之间,与ＰＥＫＫ相比,ＭｅＰＥＫＫ的结晶度、熔融温度、热分解温度均有所下降,但聚合物仍具有很好的耐热性,其溶解性得到了明显的改善。     

吲哚苯胺金属络合物近红外吸收染料中配位体的合成研究

在有氧化剂ＮａＣｌＯ水溶液或Ｎａ２Ｓ２Ｏ８存在下，分别对８－羟基喹啉或８－羟基喹哪啶与４－Ｎ，Ｎ－二烷氨基苯胺进行了氧化缩合反应，合成了１６种吲哚苯胺配位体。用ＮａＣｌＯ水溶液作氧化剂同时生成两种氧化缩合产物５－（２＇－甲基－４＇－Ｎ，Ｎ－二烷氨基苯亚氨基）－８－喹啉酮和７－氯－５－（２＇－甲基－４＇－Ｎ，Ｎ－二烷氨基苯亚氨基）－８－喹啉酮，本文用柱色谱对生成物进行了分离。用Ｎａ２Ｓ２Ｏ８作氧化剂     

低熔点芳香胺环氧固化剂的研究I,DEDDM,MEDDM,DDM的共混物

本文通过苯胺和邻乙基苯胺的混和物加入甲醛缩合得到常温下为液体的３，３＇－二乙基－４，４＇－二氨基二苯甲烷（ＤＥＭＭＤ），３－乙基－４，４＇－二氨基二苯甲烷（ＭＥＤＤＭ）和４，４＇－二氨基二苯甲烷（ＤＤＭ）的三元共混物。紫外光谱，红外光谱，色质联用谱仪均证实了这一结果。并用ＪＳＲ固化仪和热分析仪（ＤＳＣ）对该共混物固化Ｅ－５１环氧树脂的过程进行了跟踪，得到了等温和等速升温反应活化能。最后采用ＴＭＡ及     

聚硫醚酮单体及树脂的制备

研究了以４，４＇－二氯二苯酮和硫化钠为单体制备聚硫醚酮的工艺，以及４，４＇－二氯二苯酮的制备工艺，对影响因素进行了详细分析。并利用傅里叶红外光谱仪和差示扫描量热仪对聚合物的结构和性能进行了研究。     

耐热树脂共混物的界面增容研究

研究了ＰＭＲ型聚酰亚胺（ＰＩ）增容聚芳醚酮（ＰＥＫ－Ｃ）／聚苯硫醚（ＰＰＳ）共混物的热学性能、力学性能及其形态结构,对ＰＭＲ型ＰＩ在ＰＥＫ－Ｃ／ＰＰＳ共混物中所起的增容作用机理进行了初步的探讨,实验发现,热固性聚合物预聚物可用于增容热塑性聚合物共混体系,这种增容方法有其特殊性和新颖性,增容后的ＰＥＫ－Ｃ／ＰＰＳ共混物的力学性能得以改善。     

氟苯

氟苯卞觉新（合肥省化工技术情报中心站，合肥２３００４１）氟苯是医药、农药行业的重要基础原料。如由氟苯经硝化得２，４－二硝基氟苯，再氯化生成２，４－二氯氟苯。后者是合成广谱抗生素环丙沙星的起始原料。另外氟苯也是聚醚酮类超级工程塑料ＰＥＥＫ（聚醚醚酮）、...     

高纯的Z—和E—二氯烯酮的获得方法

通过Ｋｎｏｖｅｎａｇｅｌ反应制备混合Ｚ－和Ｅ－二氯烯酮、（Ｚ＋Ｅ）－１－（２，４－二氯苯基）－４，４－二甲基－２－（１，２，４－三唑－１－基）戊－１－烯－３－酮，该混合烯酮用乙醇处理得到纯度为９９．９７％的Ｚ－烯酮，分离Ｚ＝烯酮后的混合烯酮经异构化反应得到纯度为９９．７３％的Ｅ－烯酮。     

PEK－C增韧BMI／DP树脂的研究

本文以韧性较高的４，４′－氨基二苯甲烷双马来酰亚胺／３，３′－二烯丙基双酚Ａ共聚双马树脂（ＢＭＩ／ＤＰ）作为研究对象，探讨用刚性热塑性树脂ＰＥＫ－Ｃ共混的方法以进一步提高树脂韧性。结果表明，少量的ＰＥＫ－Ｃ能提高ＢＭＩ／ＤＰ树脂韧性，７．９％的ＰＥＫ－Ｃ使树脂ＧＩＣ由２１４Ｊ／ｍ２提高到４０４Ｊ／ｍ２。含活性端基ＰＥＫ－Ｃ和不同分子量的ＰＥＫ－Ｃ对树脂性能产生一定的影响。随ＰＥＫ－Ｃ用量的增加，共混树脂呈两种不同形式的球粒结构。     

PEK—C增韧BMI／DP树脂的研究

本文以韧性较高的４，４‘－氨基二苯甲烷双马来酰亚胺．３，３’－烯丙基双酚Ａ共聚双马树脂（ＢＭＩ／ＤＰ）作为研究对象，探讨用刚性热塑性树脂ＰＥＫ－Ｃ共混的方法以进一步提高树脂韧性。结果表明，少量的ＰＥＫ－Ｃ能提高ＢＭＩ／ＤＰ树脂韧性，７．９％的ＰＥＫ－Ｃ使树有ＧＩＣ的由２１４Ｊ／ｍ＾２提高到４０４Ｊ／ｍ＾２。含活性端基ＰＥＫ－Ｃ和不同分子量的ＰＥＫ－Ｃ对树脂性能产生一定的影响。随ＰＥＫ－Ｃ用量的增加     

Composites of Poly(Keto-Sulfide)–Epoxy Resin Systems and Their Thermal and Mechanical Properties

A novel matrix resin system, poly(keto-sulfide)–epoxy resin, has been developed. The poly(keto-sulfide)s (PKS), based on various ketones, formaldehyde, and sodium hydrogen sulfide (NaSH), were prepared by the reported process. These (PKS) having terminal thiol (–SH) groups were used for curing commercial epoxy resin (i.e., diglycidyl ether of bisphenol A – DGEBA), to fabricate crosslinked epoxy-poly(keto-sulfide) resin glass fiber-reinforced composites (GRC). Various epoxy/hardener (PKS) mixing ratios were used, and the curing of epoxy-PKS has been monitored using differential scanning calorimetry (DSC) in dynamic mode. Based on DSC parameters the GRC of epoxy-PKS were prepared and characterized by thermal and mechanical methods. The variation in resin/hardener ratio led to variations in thermal and mechanical properties.     

新型阳离子光固化剂双[(4-二苯硫鎓)苯]硫醚-双-六氟磷酸盐的合成

以二苯硫醚为主要原料,以过氧化氢为氧化剂,在室温条件下氧化得到了二苯亚砜.然后,二苯亚砜与二苯硫醚在硫酸的作用下,进行缩合反应制备了双[(4 二苯硫)苯]硫醚 双 六氟磷酸盐,收率由文献报道的39%提高到75%;对其结构进行了UV、IR、H NMR和元素分析.     

Analysis of the tetronomycin gene cluster: insights into the biosynthesis of a polyether tetronate antibiotic

The biosynthetic gene cluster for tetronomycin (TMN), a polyether ionophoric antibiotic that contains four different types of ring, including the distinctive tetronic acid moiety, has been cloned from Streptomyces sp. NRRL11266. The sequenced tmn locus (113 234 bp) contains six modular polyketide synthase (PKS) genes and a further 27 open-reading frames. Based on sequence comparison to related biosynthetic gene clusters, the majority of these can be assigned a plausible role in TMN biosynthesis. The identity of the cluster, and the requirement for a number of individual genes, especially those hypothesised to contribute a glycerate unit to the formation of the tetronate ring, were confirmed by specific gene disruption. However, two large genes that are predicted to encode together a multifunctional PKS of a highly unusual type seem not to be involved in this pathway since deletion of one of them did not alter tetronomycin production. Unlike previously characterised polyether PKS systems, oxidative cyclisation appears to take place on the modular PKS rather than after transfer to a separate carrier protein, while tetronate ring formation and concomitant chain release share common mechanistic features with spirotetronate biosynthesis.     

Melt Rheological Behavior and Thermal Properties of Low-Density Polyethylene/Palm Kernel Shell Composites: Effect of Polyethylene Acrylic Acid

The melt flow behavior and thermal properties of low-density polyethylene (LDPE)/palm kernel shell (PKS) composites were studied. Polyethylene acrylic acid (PEAA) was used as a compatibilizer in the composites. The results showed that the increasing of PKS loading had decreased MFI values of LDPE/PKS composites. The presence of PEAA increased the MFI values of the LDPE/PKS composites. The apparent viscosity of the composites was found to exhibit a linear relationship with the reciprocal of the temperature. Thermal properties showed that higher filler loading tended to reduce the onset temperature as the PKS possessed lower degradation temperature compared to the LDPE. The presence of the PKS in the LDPE polymeric matrix improved the thermal stability of the composites. The addition of PEAA into the composites provided better interfacial bonding between the LDPE matrix and PKS filler, while higher onset temperature and lower total weight loss were observed of LDPE/PKS composites. The activation energy of the LDPE/PKS composites was increased with increasing filler loading. At similar filler loading, the presence of PEAA increased the activation energy of the LDPE/PKS composites.     

Catalytic activity of hydrodesulfurization catalysts prepared by two methods

Two sets of samples, ranging from molybdenum sulfide to cobalt sulfide, were prepared by two different methods: homogeneous sulfide precipitation (HSP), and a new preparation method of CoMo and NiMo bulk sulfides, called impregnated thiosalt decomposition (ITD). Hydrodesulfurization of thiophene was measured at temperatures between 533 K and 593 K in a conventional flow system. The products were analyzed by gas chromatography. Both sets of samples (HSP and ITD) present the typical volcano curve of specific activity with larger values for catalysts prepared by HSP than those by ITD. Samples prepared by ITD present comparable intrinsic activities than those prepared by HSP. Activation energies for both methods of preparation are larger for promoted catalysts with a value of 23 for HSP and 12.6 kcal/mol for ITD.     

In Vitro Investigation of Crosstalk between Fatty Acid and Polyketide Synthases in the Andrimid Biosynthetic Assembly Line

Andrimid (Adm) synthase, which belongs to the type II system of enzymes, produces Adm in Pantoea agglomerans. The adm biosynthetic gene cluster lacks canonical acyltransferases (ATs) to load the malonyl group to acyl carrier proteins (ACPs), thus suggesting that a malonyl‐CoA ACP transacylase (MCAT) from the fatty acid synthase (FAS) complex provides the essential AT activity in Adm biosynthesis. Here we report that an MCAT is essential for catalysis of the transacylation of malonate from malonyl‐CoA to AdmA polyketide synthase (PKS) ACP in vitro. Catalytic self‐malonylation of AdmA (PKS ACP) was not observed in reactions without MCAT, although many type II PKS ACPs are capable of catalyzing self‐acylation. This lack of self‐malonylation was explained by amino acid sequence analysis of the AdmA PKS ACP and the type II PKS ACPs. The results show that MCAT from the organism's FAS complex can provide the missing AT activity in trans, thus suggesting a protein–protein interaction between the fatty acid and polyketide synthases in the Adm assembly line.     

Effect of filler loading and coconut oil coupling agent on properties of low‐density polyethylene and palm kernel shell eco‐composites

Palm kernel shell (PKS), a waste from the oil palm industry, has been utilized as filler in low‐density polyethylene (LDPE) eco‐composites in the present work. The effect of PKS content and coconut oil coupling agent (COCA) on tensile properties, water absorption, and morphological and thermal properties of LDPE/PKS eco‐composites was investigated. The results show the increase of PKS content decreased the tensile strength and elongation at break, but increased the tensile modulus, crystallinity, and water absorption of eco‐composites. The presence of COCA as coupling agent improved the filler‐matrix adhesion yield to increase the tensile strength, tensile modulus, crystallinity, and reduced water absorption of eco‐composites. The better interfacial adhesion between PKS and LDPE with the addition of COCA was also evidenced by scanning electron microscopy studies. J. VINYL ADDIT. TECHNOL., 22:200–205, 2016. © 2014 Society of Plastics Engineers     

A polylinker approach to reductive loop swaps in modular polyketide synthases

Multiple versions of the DEBS 1-TE gene, which encodes a truncated bimodular polyketide synthase (PKS) derived from the erythromycin-producing PKS, were created by replacing the DNA encoding the ketoreductase (KR) domain in the second extension module by either of two synthetic oligonucleotide linkers. This made available a total of nine unique restriction sites for engineering. The DNA for donor "reductive loops," which are sets of contiguous domains comprising either KR or KR and dehydratase (DH), or KR, DH and enoylreductase (ER) domains, was cloned from selected modules of five natural PKS multienzymes and spliced into module 2 of DEBS 1-TE using alternative polylinker sites. The resulting hybrid PKSs were tested for triketide production in vivo. Most of the hybrid multienzymes were active, vindicating the treatment of the reductive loop as a single structural unit, but yields were dependent on the restriction sites used. Further, different donor reductive loops worked optimally with different splice sites. For those reductive loops comprising DH, ER and KR domains, premature TE-catalysed release of partially reduced intermediates was sometimes seen, which provided further insight into the overall stereochemistry of reduction in those modules. Analysis of loops containing KR only, which should generate stereocentres at both C-2 and C-3, revealed that the 3-hydroxy configuration (but not the 2-methyl configuration) could be altered by appropriate choice of a donor loop. The successful swapping of reductive loops provides an interesting parallel to a recently suggested pathway for the natural evolution of modular PKSs by recombination.     

Fusarin C biosynthesis in Fusarium moniliforme and Fusarium venenatum

Fragments of polyketide synthase (PKS) genes were amplified from complementary DNA (cDNA) of the fusarin C producing filamentous fungi Fusarium moniliforme and Fusarium venenatum by using degenerate oligonucleotides designed to select for fungal PKS C-methyltransferase (CMeT) domains. The PCR products, which were highly homologous to fragments of known fungal PKS CMeT domains, were used to probe cDNA and genomic DNA (gDNA) libraries of F. moniliforme and F. venenatum. A 4.0 kb cDNA clone from F. venenatum was isolated and used to prepare a hygromycin-resistance knockout cassette, which was used to produce a fusarin-deficient strain of F. venenatum (kb = 1000 bp). Similarly, a 26 kb genomic fragment, isolated on two overlapping clones from F. moniliforme, encoded a complete iterative Type I PKS fused to an unusual nonribosomal peptide synthase module. Once again, targeted gene disruption produced a fusarin-deficient strain, thereby proving that this synthase is responsible for the first steps of fusarin biosynthesis.     

Evolutionary Imprint of Catalytic Domains in Fungal PKS–NRPS Hybrids

Fungal hybrid enzymes consisting of a polyketide synthase (PKS) and a nonribosomal peptide synthetase (NRPS) module are involved in the biosynthesis of a vast array of ecologically and medicinally relevant natural products. Whereas a dozen gene clusters could be assigned to the requisite PKS–NRPS pathways, the programming of the multifunctional enzymes is still enigmatic. Through engineering and heterologously expressing a chimera of PKS (lovastatin synthase, LovB) and NRPS (cytochalasin synthase, CheA) in Aspergillus terreus, we noted the potential incompatibility of a fungal highly reducing PKS (hrPKS) with the NRPS component of fungal PKS–NRPS hybrids. To rationalize the unexpected outcome of the gene fusion experiments, we conducted extensive bioinformatic analyses of fungal PKS–NRPS hybrids and LovB‐type PKS. From motif studies and the function of the engineered chimeras, a noncanonical function of C‐terminal condensation (C) domains in truncated PKS–NRPS homologues was inferred. More importantly, sequence alignments and phylogenetic trees revealed an evolutionary imprint of the PKS–NRPS domains, which reflect the evolutionary history of the entire megasynthase. Furthermore, a detailed investigation of C and adenylation (A) domains provides support for a scenario in which not only the A domain but also the C domain participates in amino acid selection. These findings shed new light on the complex code of this emerging class of multifunctional enzymes and will greatly facilitate future combinatorial biosynthesis and pathway engineering approaches towards natural product analogues.