Study On The Polymerization And Cyclopropanation Of ?-carbonyl Diazocompounds

With the development of society and the shortage of natural resources, as well as the environment disruption due to the consumption of fossil fuels, finding sustainable materials is an important issue for human society. Besides, this is also a challenge and opportunity for the researchers of polymer. Therefore, the design and synthesis of polymers with non-petroleum resources as the starting material is an important research topic for the development of polymer chemistry. This thesis mainly focuses on the polymerization and the cyclopropanation of diazoacetates due to diazoacetate can be synthesized from glycine.In chapter1, the history and features of diazo compounds were introduced. The preparation of the diazo compounds was described in detail. Most importantly, some types of reactions of diazo compounds, such as cyclopropanation and carbene polymerization, were described.In chapter2, catalyst-free copolymerization of ethyl diazoacetate (EDA) with carbethoxycarbene (CEC) had been achieved through two approaches:microwave irradiation, and enzyme-assisted (Novozyme-435) system. The structure of the copolymer was characterized by MALDI-TOF MS (m/z from2000to2450), which suggests that the main chain of the copolymer is consisted of-CH(COOEt)-and-N=N-CH(COOEt)-frameworks. Fourier transform infrared (FTIR) spectrometry, elemental analysis, and Raman spectrometry proved the incorporation of azo group in the copolymer. The results indicated that the CEC radicals were generated under microwave irradiation (with or without Novozyme-435) from EDA. The mechanism study described that the generation speed of CEC radical was faster than its polymerization, and the excess CEC radicals improved the activity of the N2C1group, thus induced some EDA molecules as radicals. The two kinds of radicals co-coupled to result in poly(CEC-co-EDA) through the C1/N2C1copolymerization, but the homopolymerization of CEC radical occurred quicker than its co-coupling with activated EDA.In chapter3, the ring-opening polymerization (ROP) of cyclic compounds (s-caprolactone) using alkyl acetate carbene (ROCOCH:) generated from diazoacetate as organocatalyst under microwave irradiation enables the one-pot preparation of copolymers of polyester and polyolefin. The chemical structure of the polymerized product was characterized by nuclear magnetic resonance (NMR), fourier transformed infrared spectroscopy (FT-IR), and ultraviolet-visible spectrophotometry (UV-vis). The incorporation of the azo group into the obtained copolymer was determined by elemental analysis. Polymer with Mn of36100g/mol and PDI of1.86was produced under optimized condition. The combination of ROP and carbene polymerization offers a new and convenient pathway to synthesize copolymers of polyesters and polyolefins.In chapter4, bisdiazo compounds were synthesized and underwent denitrogen alkene polymerization (DNAP) via the formation of an sp2carbon bond in the presence of copper(II) catalysts, affording unsaturated polymers with molecular weights in the range of2900to35400Da. The copper-catalyzed denitrogen alkene polymerization of bisdiazo compounds allows the efficient synthesis of unsaturated polyesters.In chapter5, polypyrazoles with molecular weights in the range of6500-9300g/mol and yields of71.4-82.5%were synthesized successfully through catalyst-free1,3-dipolar cycloaddition of bisdiazo compounds with bisalkynes under thermal condition and lost merely5%of their weights at temperatures higher than298?. The porous polypyrazole-copper complex with pore diameter in the range of1-2?m was prepared by the coordination of polypyrazole and copper sulfate (CuSO4), which is a reusable catalyst for the Huisgen1,3-diploar cycloaddition of alkynes and organic azides to give the corresponding triazoles with their yields over90%.In chapter6, kinetic studies of carbene polymerization of ethyl diazoacetate (EDA) by palladium (Pd) or rhodium (Rh) catalysts were investigated by real-time fourier transform infrared (FTIR) spectroscopy.(L-prolinate)RhI(1,5-cyclooctadiene)-and (L-prolinate)RhI(2,5-norbornadiene)-mediated EDA polymerization were proved as first order reactions, indicating that the formation of "Rh-carbenoid" is the rate determining step. Moreover, the reaction rate constants of (L-prolinate)RhI(1,5-cyclooctadiene) and (L-prolinate)RhI(2,5-norbornadiene)-mediated EDA polymerizations were0.00140and0.00924min-1, respectively. The activation energy (11.24kJ·mol-1) of the polymerization of "carbenes" generated from EDA with (L-prolinate)RhI(1,5-cyclooctadiene) as the catalyst was calculated from kinetic data, indicating that catalyst activation was relatively easy when starting from non-oxidized RhI(diene) species. On the other hand, the polymerizations of EDA catalyzed by three kinds of Pd-catalysts were revealed as zero order reactions, suggesting that the rate determining step involves the formation of EDA-Pd transition state complex through a coordinated step. What is more, the reaction rate constants of bis(acetonitrile)dichloropalladium, palladium acetate and palladium chloride catalyzed EDA polymerization were0.0131,0.00278, and0.000541mol·L-1·min-1, respectively. Refilling more EDA to the (bis(acetonitrile)dichloropalladium)-mediated carbene polymerization system did not change the reaction order. The rate constant increases gradually with the enlargement of the dosage of the catalyst and decreases with the cycle-index, which proves the formation of "EDA-Pd transition state complex" and the propagating species with Pd-C bonds at the end of the polymer chain. The kinetic studies indicated that the carbene polymerization is just like but not a radical polymerization reaction.In chapter7, cyclopropane derivatives were prepared without catalyst under microwave irradiation, which demonstrated it is an efficient method in organic chemistry. Compared with traditional metal catalyst, this method is convenient and less harmful to environment. A second-order process was involved in the cyclopropanation reaction according to kinetic study.In chapter8, the structure of graphene oxide (GO) enables it to act as the olefin in cyclopropanation reaction with ethyl diazoacetate (EDA) under microwave irradiation. The versatile synthetic method offers a powerful method for the rapid chemical modification of GO. The attachment of carbethoxycarbene (CEC) to GO was confirmed by the results of FTIR, XPS, Raman, and UV-vis analysis.