Constructing Pyridinic N-Rich Aromatic Ladder Structure Catalysts from Industrially Available Polyacrylonitrile Resin for Acetylene Hydrochlorination
Constructing Pyridinic N-Rich Aromatic Ladder Structure Catalysts from Industrially Available Polyacrylonitrile Resin for Acetylene Hydrochlorination
复制标题
用工业聚丙烯腈树脂构建乙炔氢氯化用吡啶类富氮芳香族梯形结构催化剂
DOI：
10.1021/acssuschemeng.9b04767
复制
发表时间：
2019
影响因子：
8.4
通讯作者：
Li Wei
中科院分区：
文献类型：
--
作者：
Qiao Xianliang;Zhao Chaoyue;Zhou Zhiqiang;Guan Qingxin;Li Wei
氮掺杂碳材料是一种很有前途的乙炔氢氯化汞催化剂的替代物。在此，我们提出了一种通过控制聚丙烯腈聚合物链的自组装来合成吡啶类富氮芳香梯形结构材料的创新策略。所制备的材料乙炔转化率> 93%，氯乙烯选择性>99%，在200 h寿命试验中表现出令人满意的稳定性。表征和密度泛函理论计算表明，催化剂的活性可能来源于梯形结构中的三种类型的活性吡啶氮中心。特别是，附近有一个H原子的吡啶N位更活跃，因为H原子可以通过H···Cl键稳定过渡态，从而降低能垒。计算了这些吡啶氮位的能垒分别为29.8和47.4 kcal mol-1，远低于附近没有氢原子的位的能垒83.2和84.4 kcal mol-1.这种简单、高效的合成具有明确形成机理的特定氮物种的策略有望为其他乙炔氢氯化绿色催化剂的设计提供帮助。
N-doped carbon material is a promising alternative to mercury catalyst for acetylene hydrochlorination. Herein, we present an innovative strategy to synthesize pyridinic N-rich aromatic ladder structure material through controlling the self-assembly of polyacrylonitrile polymer chains. The prepared material gave ∼93% conversion of acetylene with >99% selectivity for vinyl chloride and exhibited a satisfying stability during 200 h lifetime test. Characterizations and density functional theory calculations demonstrated that the activity of the catalyst likely originates from three types of active pyridinic N sites in the ladder structure. Particularly, the pyridinic N sites with one H atom nearby are more active because the H atom can stabilize the transition state through H···Cl bond, thereby reducing the energy barrier. The energy barriers on these pyridinic N sites were calculated to be 29.8 and 47.4 kcal mol–1, much lower than 83.2 and 84.4 kcal mol–1on those sites without H atom nearby. The facile and highly effective strategy for the synthesis of a specific N species with defined formation mechanism is expected to be helpful in the design of other green catalysts for acetylene hydrochlorination.