聚甲氧基二甲醚（Polyoxymethylene dimethyl ethers, PDOEn）是一种新型含氧环保柴油调和组分，其学术及应用研究均处于起步阶段。PODEn产业已成为我国新型煤化工发展的重要方向，充分契合我国能源禀赋并利于甲醇产业去产能升级。本文全面、深入地研究了PODEn的组分特性及定性定量分析方法、合成反应热力学及催化特征、聚合产物分布建模及过程优化、合成反应动力学、低凝及高凝PODEn重整反应过程、甲醇制PODEn闭路循环工艺设计等关键科学问题，为PODEn聚合产物分布调控、催化剂设计以及过程放大奠定了基础。基于ASTM标准系统地综述表征了不同聚合度PODEn组分的物化特性，并建立了无标样情况下气相色谱-质谱联用法（GC-MS）定性定量分析PODEn的方法。分析表明PODEn的组分中PODE3-5,尤其是PODE3-4,具有最适合与柴油调和的特性。PODEn组分的相对质量校正因子遵循ft(n)=(1.140)n-1的关系（以DMM为基准），该校正因子相比有效碳数法所得校正因子定量精度高。通过估算基础热力学数据，表明多聚甲醛解聚为吸热反应，PODEn合成为放热反应，二者热效应相当，整个反应体系热效应不明显。PODEn合成反应的热效应及平衡常数与聚合度n取值无关。NKC-9阳离子交换树脂在甲缩醛和多聚甲醛合成PODEn反应过程中具有优异的催化性能，聚合反应遵循逐步聚合反应机理。基于逐步聚合反应机理，理论推导瞬态和平衡态PODEn产物分布均符合Schulz-Flory模型，该模型具有良好的预测能力；采用响应曲面法综合考虑PDI和XCH2O的优化，操作点（T=105 oC，M=1.1）对应最高的醛转化率XCH2O = 92.4 %。甲缩醛和多聚甲醛合成PODEn的动力学模型假设各级聚合反应系可逆反应(二级聚合，一级解聚)，聚合反应kp和解聚反应kd的活化能分别为39.52和52.01 kJ?mol–1，活化因子分别为 1.84 × 107 L?mol–1?min–1和5.36 × 106 min–1；本动力学模型中PODEn合成反应速率常数随n变化而保持恒定；该模型具有良好的预测能力。 针对甲缩醛和多聚甲醛合成PODEn工艺中低凝（PODE1-2）及高凝（PODEn>4）物流的循环利用，研究了上述物流的重整反应过程。研究表明，相同操作条件下，PODEn体系重整反应平衡产物分布仅取决于DMM/CH2O摩尔当量，为设计零副产的PODEn合成工艺中提供了指导和依据。
Polyoxymethylene dimethyl ethers (PODEn) is a novel green oxygenated blending compounds to diesel fuel. Academic and application researches on PODEn are still in primary stage. The PODEn industry has been an important new branch of coal chemical industry. Methanol to PODEn technology provides a route consuming the overcapacity of methanol industry. In this dissertation, comprehensive studies were carried out on key scientific problem such as properties and quantitatively anlaysis method of PODEn, thermodynamics and catalysis behavior, compounds distribution of PODEn and the process optimization, reaction kinetics, reforming reaction of undersized or oversized PODEn. The above studies laid a solid foundation for regulating compounds distribution of PODEn, designing of catalyst and process scale-up in syntheisi of PODEn. Systematically analysis were performed to characterize the properties of PODEn and PODEn-Diesel blending fuel refeering to ASTM standards, and to found a method of determining the correction factors in gas chromatography of PODEn compounds without using standard samples. Results showed that PODE3-5, espeicially PODE3-4, provided the best properties as diesel blending compoudns. The relative mass calibration factors of PODEn compounds followed ft(n)=(1.140)n-1 (referring to DMM with factor 1) and showed better quantitatively analysis accurity compared with factors calculzted by effective carbon numbers method.Thermodynamic analysis showed that depolymerization reactions of paraformaldehyde were endothermic while the synthesis reactions of PODEn were exothermic, and the overall system showed a weak thermal effect. The thermal effect data and equilibrium constants are the same with different n values. NKC-9 cation exchange resin showed outstanding catalystic performance in synthesis of PODEn from DMM and paraformaldehyde, during which a step-by-step polymerization reaction mechanism was obeyed.A theoretical analysis of the transient or equilibrium molecular size distribution of PODEn synthesized from DMM and paraformaldehyde was performed based on a sequential reaction mechanism. Results found that both the transient or equilibrium molecular size distribution of PODEn followed Schulz-Flory model and showed a good prediction ability. Response surface methodology found the optimum operating conditions of T = 105 oC and M = 1.1, the conversion of formaldehyde XCH2O has a high value of 92.4%.The sequential reversible reactions to produce PODEn were verified to follow a second-order kinetics for propagation and a first-order kinetics for depolymerization. The rate constants of propagation (kp) and depolymerization (kd) were the same for the series of PODEn synthesis reactions. Herein, the pre-exponential factors Ap for propagation and Ad for depolymerization were 1.84 × 107 L?mol–1?min–1 and 5.36 × 106 min–1, respectively. The activation energy Ep (39.52 kJ?mol–1) for propagation was lower than Ed (52.01 kJ?mol–1) for depolymerization.For recycling the undersized PODE1-2 and oversized PODEn>4 in PODEn process from DMM and paraformaldehyde, reforming reactions of undersized or oversized PODEn were performed. Results showed that the equilibrium compounds distribution is only determined by the value of equivalent DMM/CH2O molar ratio under the same other conditions, thus providing guidance and reference for designing a close-loop methanol to PODEn process
