Vapour-Phase Selective <i>O</i>-Methylation of Catechol with Methanol over Metal Phosphate Catalysts
Guaiacol (2-methoxyphenol), an important fine chemical intermediate, is conventionally synthesized by liquid-phase processes with expensive, corrosive and toxic methylating agents such as dimethyl sulphate and dimethyl iodide. Recently, vapour-phase alkylation of catechol (1, 2-dihydroxybenzene) wit...
| Main Authors: | , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2021-04-01
|
| Series: | Catalysts |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2073-4344/11/5/531 |
| _version_ | 1797536937551069184 |
|---|---|
| author | Haifang Mao Xiaolei Li Fen Xu Zuobing Xiao Wenxiang Zhang Tao Meng |
| author_facet | Haifang Mao Xiaolei Li Fen Xu Zuobing Xiao Wenxiang Zhang Tao Meng |
| author_sort | Haifang Mao |
| collection | DOAJ |
| description | Guaiacol (2-methoxyphenol), an important fine chemical intermediate, is conventionally synthesized by liquid-phase processes with expensive, corrosive and toxic methylating agents such as dimethyl sulphate and dimethyl iodide. Recently, vapour-phase alkylation of catechol (1, 2-dihydroxybenzene) with methanol for the synthesis of guaiacol in the presence of heterogeneous catalysts has received more attention, as the route is economical and environmentally friendly. However, most of the investigated catalysts exhibited unsatisfactory catalytic performance for industrial applications. In this study, five metal phosphates M-P-O (M = La, Ce, Mg, Al, Zn) catalysts were synthesized and tested in the selective <i>O</i>-methylation of catechol with methanol. Among these catalysts, cerium phosphate (CP) showed the highest catalytic activity and guaiacol yield. Lanthanum phosphate (LP) was the second most active, which was still obviously better than magnesium phosphate (MP) and aluminium phosphate (ALP). Zinc phosphate (ZP) was not active in the reaction. Relevant samples were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), scanning electron microscopy (SEM), N<sub>2</sub> adsorption-desorption, temperature programmed desorption of NH<sub>3</sub> or CO<sub>2</sub> (NH<sub>3</sub>-TPD, CO<sub>2</sub>-TPD). The suitable acid-base properties contribute to the superior catalytic performance of CP. Long-term stability and regeneration tests were also studied. |
| first_indexed | 2024-03-10T12:07:56Z |
| format | Article |
| id | doaj.art-c05060c30db64620bd444902bdd7f152 |
| institution | Directory Open Access Journal |
| issn | 2073-4344 |
| language | English |
| last_indexed | 2024-03-10T12:07:56Z |
| publishDate | 2021-04-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Catalysts |
| spelling | doaj.art-c05060c30db64620bd444902bdd7f1522023-11-21T16:29:18ZengMDPI AGCatalysts2073-43442021-04-0111553110.3390/catal11050531Vapour-Phase Selective <i>O</i>-Methylation of Catechol with Methanol over Metal Phosphate CatalystsHaifang Mao0Xiaolei Li1Fen Xu2Zuobing Xiao3Wenxiang Zhang4Tao Meng5School of Chemical and Environmental Engineering, Shanghai Institute of Technology, Shanghai 201418, ChinaSchool of Chemical and Environmental Engineering, Shanghai Institute of Technology, Shanghai 201418, ChinaSchool of Chemical and Environmental Engineering, Shanghai Institute of Technology, Shanghai 201418, ChinaSchool of Perfume and Aroma Technology, Shanghai Institute of Technology, Shanghai 201418, ChinaCollege of Chemistry, Jilin University, Changchun 130023, ChinaSchool of Chemical and Environmental Engineering, Shanghai Institute of Technology, Shanghai 201418, ChinaGuaiacol (2-methoxyphenol), an important fine chemical intermediate, is conventionally synthesized by liquid-phase processes with expensive, corrosive and toxic methylating agents such as dimethyl sulphate and dimethyl iodide. Recently, vapour-phase alkylation of catechol (1, 2-dihydroxybenzene) with methanol for the synthesis of guaiacol in the presence of heterogeneous catalysts has received more attention, as the route is economical and environmentally friendly. However, most of the investigated catalysts exhibited unsatisfactory catalytic performance for industrial applications. In this study, five metal phosphates M-P-O (M = La, Ce, Mg, Al, Zn) catalysts were synthesized and tested in the selective <i>O</i>-methylation of catechol with methanol. Among these catalysts, cerium phosphate (CP) showed the highest catalytic activity and guaiacol yield. Lanthanum phosphate (LP) was the second most active, which was still obviously better than magnesium phosphate (MP) and aluminium phosphate (ALP). Zinc phosphate (ZP) was not active in the reaction. Relevant samples were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), scanning electron microscopy (SEM), N<sub>2</sub> adsorption-desorption, temperature programmed desorption of NH<sub>3</sub> or CO<sub>2</sub> (NH<sub>3</sub>-TPD, CO<sub>2</sub>-TPD). The suitable acid-base properties contribute to the superior catalytic performance of CP. Long-term stability and regeneration tests were also studied.https://www.mdpi.com/2073-4344/11/5/531metal phosphatescatecholmethanol<i>O</i>-methylationguaiacol |
| spellingShingle | Haifang Mao Xiaolei Li Fen Xu Zuobing Xiao Wenxiang Zhang Tao Meng Vapour-Phase Selective <i>O</i>-Methylation of Catechol with Methanol over Metal Phosphate Catalysts Catalysts metal phosphates catechol methanol <i>O</i>-methylation guaiacol |
| title | Vapour-Phase Selective <i>O</i>-Methylation of Catechol with Methanol over Metal Phosphate Catalysts |
| title_full | Vapour-Phase Selective <i>O</i>-Methylation of Catechol with Methanol over Metal Phosphate Catalysts |
| title_fullStr | Vapour-Phase Selective <i>O</i>-Methylation of Catechol with Methanol over Metal Phosphate Catalysts |
| title_full_unstemmed | Vapour-Phase Selective <i>O</i>-Methylation of Catechol with Methanol over Metal Phosphate Catalysts |
| title_short | Vapour-Phase Selective <i>O</i>-Methylation of Catechol with Methanol over Metal Phosphate Catalysts |
| title_sort | vapour phase selective i o i methylation of catechol with methanol over metal phosphate catalysts |
| topic | metal phosphates catechol methanol <i>O</i>-methylation guaiacol |
| url | https://www.mdpi.com/2073-4344/11/5/531 |
| work_keys_str_mv | AT haifangmao vapourphaseselectiveioimethylationofcatecholwithmethanolovermetalphosphatecatalysts AT xiaoleili vapourphaseselectiveioimethylationofcatecholwithmethanolovermetalphosphatecatalysts AT fenxu vapourphaseselectiveioimethylationofcatecholwithmethanolovermetalphosphatecatalysts AT zuobingxiao vapourphaseselectiveioimethylationofcatecholwithmethanolovermetalphosphatecatalysts AT wenxiangzhang vapourphaseselectiveioimethylationofcatecholwithmethanolovermetalphosphatecatalysts AT taomeng vapourphaseselectiveioimethylationofcatecholwithmethanolovermetalphosphatecatalysts |