A green, rapid and continuous hydrothermal flow synthesis (CHFS) route has been employed to synthesise highly efficient and active novel heterogeneous catalysts. Tin doped zirconia (Zr–Sn–O) and tin doped zirconia/graphene nanocomposite (Zr–Sn/GO) have been assessed as suitable heterogeneous catalysts for the synthesis of dimethyl carbonate (DMC). The catalysts have been extensively characterized using powder X-ray diffraction (XRD), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET) surface area measurement and X-ray photoelectron spectroscopy (XPS) analysis. Extensive batch studies for the synthesis of DMC via the transesterification of propylene carbonate (PC) and methanol (MeOH) using Zr–Sn/GO catalyst in a solvent free process were also conducted. The effect of various reaction conditions such as reactant molar ratio, catalyst loading, reaction temperature and reaction time has been extensively evaluated. Response surface methodology based on Box-Behneken Design (BBD) was employed to derive optimum conditions for maximising PC conversion and DMC yield. The correlations and interactions between various variables such as MeOH:PC ratio, catalyst loading, reaction temperature, reaction time and stirring speed were extensively studied. A quadratic model by multiple regression analysis for the PC conversion and DMC yield was developed and verified by several methods BBD revealed that optimum conditions for high yield values of DMC are 12.33:1 MeOH:PC molar ratio, 446.7 K, 4.08 h and 300 rpm using 2.9% (w/w) Zr–Sn/GO nanocomposite. The maximum predicted responses at the optimum conditions are 85.1% and 81% for PC conversion and yield of DMC respectively. Experimental results at optimum model predicted reaction conditions agree very well with the model predicted response, where 82.4% PC conversion and 78.2% yield of DMC were obtained. Catalyst reusability and stability studies have been conducted at optimum reaction condition to investigate the long term stability of Zr–Sn/GO and it has been found that the catalyst could be reused more than six times (about 42 h) without losing its catalytic activity. These experimental and model predicted values showed an excellent agreement for tin doped zirconia/graphene nanocomposite as a heterogeneous catalyst for the synthesis of DMC from PC and MeOH.

绿色，快速和连续的水热流合成（CHFS）路线已被用来合成高效和活性的新型多相催化剂。锡掺杂的氧化锆（Zr–Sn–O）和锡掺杂的氧化锆/石墨烯纳米复合材料（Zr–Sn / GO）被评估为适合合成碳酸二甲酯（DMC）的非均相催化剂。催化剂已使用粉末X射线衍射（XRD），透射电子显微镜（TEM），Brunauer-Emmett-Teller（BET）表面积测量和X射线光电子能谱（XPS）分析进行了广泛表征。广泛的批处理研究，用于通过DFM合成DMC还使用Zr–Sn / GO催化剂在无溶剂工艺中进行了碳酸亚丙酯（PC）和甲醇（MeOH）的酯交换反应。已经广泛评估了各种反应条件的影响，例如反应物摩尔比，催化剂负载，反应温度和反应时间。采用基于Box-Behneken设计（BBD）的响应面方法来获得最佳条件，以使PC转化率和DMC产量最大化。广泛研究了MeOH：PC比，催化剂负载量，反应温度，反应时间和搅拌速度等各种变量之间的相关性和相互作用。通过多次回归分析得出了PC转化率和DMC收率的二次模型，并通过多种方法进行了验证。BBD表明，DMC高收率值的最佳条件为12.33：1 MeOH：使用2.9％（w / w）Zr–Sn / GO纳米复合材料的PC摩尔比为446.7 K，4.08 h和300 rpm。在最佳条件下，PC转化率和DMC收率的最大预测响应分别为85.1％和81％。在最佳模型预测的反应条件下的实验结果与模型预测的响应非常吻合，其中获得了82.4％的PC转化率和78.2％的DMC收率。在最佳反应条件下进行了催化剂可重复使用性和稳定性研究，以研究Zr-Sn / GO的长期稳定性，发现该催化剂可重复使用六次以上（约42小时）而不会失去其催化活性。这些实验和模型预测值表明，掺杂锡的氧化锆/石墨烯纳米复合材料可作为从PC和MeOH合成DMC的非均相催化剂，具有极好的一致性。