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Synergistic Bimetallic Pd–Pt/TiO2 Catalysts for Hydrogenolysis of Xylitol with In Situ-Formed H2
Industrial & Engineering Chemistry Research ( IF 3.8 ) Pub Date : 2020-07-12 , DOI: 10.1021/acs.iecr.0c01564
Qi Xia 1 , Guangyu Zhang 1 , Jinyao Wang 1 , Wenxiang Zhang 1 , Mengyuan Liu 1 , Yushan Li 1 , Bin Yin 1 , Chaohe Yang 1 , Jian Shen 2 , Xin Jin 1
Affiliation  

Hydrogenolysis of xylitol can produce value-added glycols and alcohols for industrial chemicals. However, it is often carried out under elevated temperature and pressure, causing unfavorable catalyst deactivation and significant formation of side products. Catalytic transfer hydrogenolysis of xylitol, under much milder conditions, is largely unexplored in this field. Herein, we reported transfer hydrogenolysis of xylitol with in situ-formed H2 in batch slurry reactors over synergistic Pd–Pt/TiO2 catalysts. Although monometallic Pd/TiO2 and Pt/TiO2 catalysts display poor activity and selectivity, bimetallic Pd–Pt/TiO2 catalysts showed synergetic performances for tandem H2 generation and hydrogenolysis of xylitol. A combined yield of 41.1% to propylene glycol and ethylene glycol was thus obtained on the Pd–Pt/TiO2 catalyst at 220 °C and 1 MPa N2. Detailed structure-dependency studies on PdPt particle size (2.4–5.2 nm) revealed that C–H, C–O, and C–C bond cleavage displays strong size-determining trends. Therefore, conversion of xylitol displays an optimal selectivity toward glycols and alcohols with a PdPt particle size of approximately 4.4 nm. In addition, influence of experimental parameters, including temperature (200–230 °C), N2 pressure (0–3 MPa), and alkali/xylitol molar ratio (0–0.25), was also studied with respect to conversion and production distribution. The outcome of this work offers mechanistic insights into atom-efficient conversion of bioderived oxygenates to renewable chemicals.

中文翻译:

木糖醇加氢原位生成H 2协同双金属Pd–Pt / TiO 2催化剂

木糖醇的氢解可产生用于工业化学品的增值二醇和醇。然而,它通常在高温和高压下进行,导致不利的催化剂失活和明显形成副产物。在更温和的条件下,木糖醇的催化转移氢解在该领域中尚待探索。在本文中,我们报道了在间歇式淤浆反应器中在协同Pd–Pt / TiO 2催化剂上木糖醇与原位形成的H 2的转移氢解反应。尽管单金属Pd / TiO 2和Pt / TiO 2催化剂显示出较差的活性和选择性,但双金属Pd-Pt / TiO 2催化剂显示了串联H的协同性能。木糖醇的第2代和氢解。因此,在220°C和1 MPa N 2的Pd–Pt / TiO 2催化剂上,丙二醇和乙二醇的总收率为41.1%。对PdPt粒径(2.4–5.2 nm)的详细结构依赖性研究表明,C–H,C–O和C–C键裂解显示出强烈的尺寸决定趋势。因此,木糖醇的转化对PdPt粒径约为4.4 nm的二醇和醇显示出最佳的选择性。另外,实验参数的影响,包括温度(200–230°C),N 2还研究了转化率和生产分布方面的压力(0–3 MPa)和碱/木糖醇摩尔比(0–0.25)。这项工作的结果为将生物来源的含氧化合物原子转化为可再生化学品提供了有效的机械方法。
更新日期:2020-08-05
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