【作者】 郭明星；

【导师】 王祥生； 郭洪臣；

【作者基本信息】 大连理工大学 ， 工业催化， 2006， 博士

【摘要】 环氧丙烷、丙醛、丙烯醛和丙酮这四种C₃氧化产物（尤其是环氧丙烷和丙醛）都是有机化工的重要中间体。近二十多年来,国内外研究者一直致力于流程简单、副产物少和无污染的生产C₃氧化产物（尤其是环氧丙烷）的绿色催化工艺的研究。其中,又以分子氧（O₂或Air）直接气相氧化丙烯这一催化工艺最简单,生产成本最低。但是由于丙烯分子具有一个含有活泼α-H的甲基,这使得丙烯的氧化反应变得复杂。因此,以分子氧（O₂或Air）为氧化剂进行丙烯直接氧化反应成为催化界最具挑战性的课题之一。 非平衡等离子体是一种非常有效的活化分子手段。在等离子体中,电子通过电场加速而获得足够高的能量（1-10eV）,使反应物分子激发、离解和电离,形成高活化状态的反应物种。而且放电反应几乎不引起体系温度上升,体系温度可保持在室温或略高于室温。氧气在非平衡等离子体活化条件下可生成O^-,O₂^-,O,O₂⁺和O⁺等活性形式,这使得丙烯的选择性氧化成为可能。 迄今为止,国内外尚未发现有将非平衡等离子体放电手段用于直接活化分子氧进行丙烯气相氧化反应的相关报道。 本论文在室温常压下,以O₂或Air为氧化剂,采用非平衡等离子体（脉冲电晕放电等离子体和介质阻挡放电等离子体）活化手段,进行直接气相氧化丙烯生成C₃氧化产物（环氧丙烷、丙醛、丙烯醛和丙酮）反应。反应过程中,不用有机氧载体,不需加入催化剂,只用分子氧（O₂或Air）在等离子体反应器中直接产生活性氧物种,原料廉价清洁,操作过程简单,无设备腐蚀和环境污染问题,属于低成本一步法制C₃氧化产物的绿色合成路线。 本论文取得的主要结果如下: 1、研制出用于丙烯选择性氧化的脉冲电晕放电等离子体反应器。在该反应器中,以氧气为氧化剂,在室温常压下实现了丙烯气相氧化合成C₃氧化产物（PO、丙醛、丙酮和丙烯醛）。在极间距为4mm,V（C₃H₆）/V（O₂）=1:99,反应气总流速为200ml/min,脉冲放电电压为18kV,放电频率为120Hz的条件下,丙烯转化率、C₃氧化产物的总选择性及总收率分别为19.2%、52.5%和10.1%。在本论文实验条更多还原

【Abstract】 Propylene oxide （PO）, propionaldehyde, acrolein and acetone are one of the most important chemical feedstocks. Molecular oxygen is the best oxidant due to low cost and significant advantages for the environment. Because the allylic protons of propylene possess high acidity, propylene is easily oxidized to acrolein but is difficultly oxidized to propylene oxide or acetone by molecular oxygen. So, gas phase propylene oxidation to prepare C₃ partial oxidation products （especially PO） with molecular oxygen as the oxidant is the most desirable reaction and is one of the most challenging topics in catalysis.The pulse corona plasma and dielectric barrier discharge plasma are typical non-equilibrium cold plasma in a gas at atmospheric pressure. They are excellent source of energetic electrons with 1-10 eV and high density. Their unique advantages are to generate low excited atomic and molecular species, free radicals and excimers with several electron volt energy. The electron temperature is very high, yet the ionic or molecular temperature is rather low in non-equilibrium cold plasma.In this paper, C3 partial oxidation products （PO, propionaldehyde, acrolein and acetone） were obtained by oxidizing propylene directly using O₂ or air as oxidant at room temperature and atmospheric pressure, and the reaction was activated by pulse corona plasma and dielectric barrier discharge plasma. Active oxygen species were utilized by using molecular oxygen （O2 or air） as oxidant and organic oxygen carrier and catalyst were not needed in the process of reaction. This technique was one-step and low cost green-synthesis route of C3 partial oxidation products （PO, propionaldehyde, acrolein and acetone）, which was due to cheap raw material, simple operatione process and without equipment corrosion or environmental pollution.The following results were obtained:1. The reaction of direct gas phase oxidation to C3 partial oxidation products （PO, propionaldehyde, acrolein and acetone） of propylene can be driven using O₂ as oxidant by means of pulse corona plasma without catalyst at room temperature and atmosphere pressure. When total flow rate was 200ml/min, space between electrodes was 4mm, pulse discharge voltage was 18kV and discharge frequency was 120Hz, the conversion of propylene, the total selectivity and total yield of C3 partial oxidation products were 19.2%, 52.5% and 10.1%, respectively. The discharge parameters, structure of reactor, space between electrodes, ratio of V（C₃H₆） to V（O₂） and total flow rate were main factors that affected the reaction under pulse corona plasma.2. C3 partial oxidation products （PO, propionaldehyde, acrolein and acetone） were successfully prepared from propylene and Ot directly by method of dielectric barrier discharge plasma at room temperature and atmosphere pressure. When electrode was made of stainless steel, the total flow rate was 160.8ml/min, discharge frequency was 1.38kHz, ratio of F（C3H6） to V（O2） was 1:200, and dielectric barrier discharge voltage was 21kV, the conversion of propylene, the total selectivity and total yield of C3 partial oxidation products were 81.6%, 43.0% and 35.1%, respectively. The ratio of V(Ct,H（） to F（C>2） caused a great effect on products distribution. The dielectric barrier discharge voltage has an effect on the conversion of propylene, total selectivity and yield of C3 partial oxidation products, composition and distribution of products. It is very advantageous for the conversion of propylene and disadvantageous for the total yield of C3 partial oxidation products and other organic oxides under intermediate frequency, but, C3 total yield increases under low frequency. The total flow rate affects the conversion of propylene, the selectivities of C3 and other products at a certain extent.3, The reaction of direct gas phase oxidation of propylene to prepare C3 partial oxidation products （PO, propionaldehyde, acrolein and acetone） can be driven using air as oxidant by means of dielectric barrier discharge plasma with water electrode at room temperature and atmosphere pressure. When total flow rate was 40.4ml/min, dielectric barrier discharge voltage was 21.5kV, dielectric barrier discharge frequency was 1.38kHz and ratio of F（C3H6） to F（air） was 1:99, the conversion of propylene, the total selectivity and total yield of C3 partial oxidation products were 63.5%, 52.4% and 33.3%, respectively. The dielectric barrier discharge voltage has a crucial effect on propylene conversion and selectivity of products. The composition of glass reactors has a great effect on propylene epoxidation reaction under dielectric barrier discharge plasma. The glass composition of more SiC>2 and less B2O3 is effective for conversion of propylene and PO yield, moreover, this composition inhibits also further oxidated reaction of products at a certain extent. Other condations is same, With the increase of the length of reactor and the inside diameter of water electrode, the conversion of propylene increases, the selectivities of C3 partial oxidation products decrease, the selectivities of other products increase. The proportion and the total flow rate of reaction gas have effect on the conversion of propylene, the total yield of C3 partial oxidation products and other products distribution at a certain extent.更多还原