Suryandari Ade Sonya, Nurtono Tantular, Widiyastuti Widiyastuti, Setyawan Heru
Department of Chemical Engineering, Faculty of Industrial Technology and System Engineering, Sepuluh Nopember Institute of Technology, Kampus ITS Sukolilo, Surabaya 60111, Indonesia.
Department of Chemical Engineering, Politeknik Negeri Malang, Jl. Soekarno-Hatta No. 9, Malang 65141, Indonesia.
ACS Omega. 2023 Jul 24;8(30):27139-27145. doi: 10.1021/acsomega.3c02244. eCollection 2023 Aug 1.
The hydrophilicity of sulfonic acid-functionalized solid catalysts tends to accelerate the deactivation of the catalyst for chemical reactions where water is produced during the process. In this work, we proposed a hydrophobic carbon aerogel acid catalyst derived from coir fibers by a sulfonation-hydrophobization route via the diazo reduction method. Sulfonation using the diazo reduction method offers some advantages such as the process takes only a few minutes and the modified surface can be easily modified further to be hydrophobic. The carbon aerogel was produced by direct pyrolysis of cellulose aerogels derived from coir fibers using an NHOH-urea method and then sulfonated and hydrophobized using sulfanilic acid and 4--butylaniline (TBA), respectively. The carbon aerogel exhibited a very high surface area (2624.93-3911.05 m g), which provides a lot of number of sites for sulfonate groups (2.30-2.70 mmol g). The water contact angle of the sulfonated catalyst after hydrophobization ranged from 70 to 115°, depending on the mass ratio of the TBA-to-solid catalyst. The hydrophobic catalyst exhibited better catalytic performance toward esterification of acetic acid with ethanol. A conversion of 65-74% could be achieved in a brief time using the hydrophobic catalyst. The conversions were much higher than that obtained by the unmodified hydrophilic catalyst. Our study offers a strategy to tune the surface hydrophobicity of the sulfonated solid acid catalyst to match for specific chemical reactions.
磺酸官能化固体催化剂的亲水性往往会加速催化剂在过程中产生水的化学反应中的失活。在这项工作中，我们通过重氮还原法，经由磺化-疏水化路线，提出了一种由椰壳纤维衍生的疏水性碳气凝胶酸催化剂。使用重氮还原法进行磺化具有一些优点，例如该过程仅需几分钟，且改性表面可轻松进一步改性为疏水性。碳气凝胶是通过使用NHOH-尿素法对椰壳纤维衍生的纤维素气凝胶进行直接热解制备的，然后分别使用对氨基苯磺酸和4-丁基苯胺（TBA）进行磺化和疏水化处理。该碳气凝胶具有非常高的比表面积（2624.93 - 3911.05 m²/g），为磺酸基团提供了大量的位点（2.30 - 2.70 mmol/g）。疏水化后磺化催化剂的水接触角在70°至115°之间，这取决于TBA与固体催化剂的质量比。该疏水催化剂对乙酸与乙醇的酯化反应表现出更好的催化性能。使用该疏水催化剂可在短时间内实现65% - 74%的转化率。这些转化率远高于未改性的亲水性催化剂所获得的转化率。我们的研究提供了一种调节磺化固体酸催化剂表面疏水性以匹配特定化学反应的策略。
