Home R & D Nano IACS, Kolkata Researchers Develop Novel Method for Reducing Sulfur Dioxide Pollution

IACS, Kolkata Researchers Develop Novel Method for Reducing Sulfur Dioxide Pollution

IACS, Kolkata Researchers Develop Novel Method for Reducing Sulfur Dioxide Pollution

Researchers at the Indian Association for the Cultivation of Science (IACS) in Kolkata have made a breakthrough in the reduction of sulfur dioxide (SO2) to fixed forms of sulfur. The team, led by Dr. Abhishek Dey, has demonstrated that iron(II) tetraphenylporphyrin can reduce SO2 to sulfur monoxide (SO), mimicking the action of the naturally occurring heme enzyme sulfite reductase (SiR).

This discovery could have significant implications for addressing the growing concerns surrounding SO2’s detrimental effects on health and the environment and enabling its conversion into valuable chemicals. The findings, published in the journal “Angewandte Chemie“, were a result of a combination of spectroscopic data and theoretical calculations, which indicate that the reduction of SO2 by iron(II) tetraphenylporphyrin results in the formation of an intermediate [FeIII−SO]+ species, similar to the one proposed for SiR. The research team at IACS, Kolkata, is further planning to explore the possibilities of its application in the industrial and environmental sector.

Bullet point summary:

  • SO2 is a major atmospheric pollutant emitted from fossil fuel burning and smelters
  • SiR is an enzyme that is known to reduce SO2 to H2S and is an integral part of the global sulfur cycle
  • However, its action has not yet been mimicked in artificial systems outside of the protein matrix
  • The reduction of SO2 to SO using FeIITPP is demonstrated and supported by spectroscopic data and theoretical calculations
  • The SO obtained from the chemical reduction of SO2 could be used in the form of a cheletropic adduct of butadiene resulting in an organic sulfoxide

Sulfur dioxide (SO2) is a major atmospheric pollutant that is emitted from fossil fuel burning and smelters. The detrimental effects of SO2 on health and the environment have been a growing concern, and finding ways to valorize SO2 into valuable chemicals is an important goal. The naturally occurring heme enzyme sulfite reductase (SiR) is known to reduce SO2 to H2S and is an integral part of the global sulfur cycle. However, despite several decades of research on the enzyme’s structure, its action has not yet been mimicked in artificial systems outside of the protein matrix.

This study demonstrates the reduction of SO2 to SO using iron(II) tetraphenylporphyrin (FeIITPP). The reaction of ferrous tertraphenylporphyrin (10 M, THF) with SO2 (SO2 saturated THF, 0.3-0.5 M) at room temperature was investigated. The results indicate that SO2 is reduced to SO via a [FeIIISO]+ intermediate species, mimicking the first step in the catalytic cycle of the enzyme. A combination of spectroscopic data and theoretical calculations support this conclusion.

The SO obtained from the chemical reduction of SO2 could be used in the form of a cheletropic adduct of butadiene resulting in an organic sulfoxide. Overall, this breakthrough in mimicking the action of SiR has the potential to address concerns about the detrimental effects of SO2 on health and the environment and valorize SO2 into valuable chemicals.

Outcomes:

  • Successful demonstration of reduction of sulfur dioxide (SO2) to sulfur monoxide (SO) using iron(II) tetraphenylporphyrin, mimicking the action of the naturally occurring enzyme sulfite reductase (SiR)
  • Potential to address concerns about the detrimental effects of SO2 on health and the environment, as well as valorization of SO2 into valuable chemicals

Reduction of Sulfur Dioxide to Sulfur Monoxide by Ferrous Porphyrin**

Bhattacharya; Kumar; Ghatak; Nayek; Dinda; Saha; Ghosh Dey; Dey

What this paper is about

  • An estimated > 100 Tg of SO 2 is emitted annually; mostly from human activities.
  • The enzyme responsible for the 6e /6H + reduction of SO 2 to H 2 S in these bacteria is sulfite reductase.
  • The SiRs feature a siroheme cofactor in its active site, which is a member of the isobacteriochlorin family of heme cofactors.

What you can learn

  • Although there are no precedent for EPR of metal-bound SO complexes, SO has a triplet ground state like O 2 and an antiferromagnetic coupling of a S = 1/2 Fe III with an S = 1 SO is expected to result in a S = 1/2 ground state with an EPR signal like those reported for 7 species, which are described as an S = 1/2 Fe III center antiferromagnetically coupled to an S = 1 NO.
  • The resonance Raman data of the Fe II TPP + SO 2 reaction at room temperature show only a high-spin ferric porphyrin species as the final product, which is consistent with the observed decay of the S = 1/2.
  • Fe III SO] + intermediate to the HS Fe III porphyrin product as observed in EPR and Mssbauer data.
  • B GC-MS chromatogram of the Fe II TPP + DMB + SO 2 reaction mixture, the control reaction mixture of Na 2 S + SO 2 + DMB, the synthesized standard DMB-SO, and CHCl 3 solvent.
  • In summary, the data show that ferrous porphyrin can reduce SO 2 similar to the known reactivity of sirohemebased sulfite reductase.

Question 1: What is the main concern about sulfur dioxide (SO2)?

Answer: The main concern about sulfur dioxide (SO2) is its detrimental effect on health and the environment.

Question 2: What is sulfite reductase (SiR)?

Answer: Sulfite reductase (SiR) is a naturally occurring heme enzyme that reduces SO2 to H2S and is an integral part of the global sulfur cycle.

Question 3: What is the goal of the paper “Reduction of Sulfur Dioxide to Sulfur Monoxide by Ferrous Porphyrin”?

Answer: The goal of the paper “Reduction of Sulfur Dioxide to Sulfur Monoxide by Ferrous Porphyrin” is to demonstrate the reduction of SO2 by iron(II) tetraphenylporphyrin and to mimic the action of the enzyme sulfite reductase (SiR) in artificial systems outside of the protein matrix.

Question 4: What is the intermediate species formed in the reduction of SO2 by ferrous tetraphenylporphyrin?

Answer: The intermediate species formed in the reduction of SO2 by ferrous tetraphenylporphyrin is [FeIII−SO]+

Question 5: What is the end product of SO2 reduction by ferrous tetraphenylporphyrin?

Answer: The end product of SO2 reduction by ferrous tetraphenylporphyrin is sulfur monoxide (SO) via the intermediate species [FeIIISO]+

Question 6: What are the main sources of SO2 emission?

Answer: The main sources of SO2 emission are human activities such as fossil fuel burning and smelters.

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