Extraction and purification of 2-hydroxymuconic semialdehyde accumulated in phenol degradation by Pseudomonas stutzeri N2

2-Hydroxymuconic semialdehyde (2-HMS) is a useful intermediate in organic synthesis, but there are few reports for its preparation. 2-HMS accumulates in phenol-containing wastewater treated with Pseudomonas stutzeri N2. This work has studied the extraction of 2-HMS so that the phenolic wastes of high concentration may be used to produce 2-HMS. When 4.25 mmol/L phenol was degraded by Pseudomonas stutzeri N2, the accumulated 2-HMS can reach 3.79 ± 0.08 mmol/L within 30 h. A saturated solution of NaHSO 3 was added into the 2-HMS culture, and white rod-like precipitates formed gradually. Through SEM, XRD and FT-IR, the precipitates were identified as monoclinic hexagonal crystals of α-hydroxy sulfonate sodium with high purity. In the presence of NaOH, α-hydroxy sulfonate sodium could be reduced to the desired 2-HMS product. The optimized conditions were characterized to be 3 mol/L NaOH solution, 5 min and 50 °C. The conversion rate of α-hydroxy sulfonate sodium was up to 87.3 ± 0.2%, and 0.42 ± 0.02 mmol/L 2-HMS were obtained.