Editing Demethylation (section)

==Biomass processing==
Methoxy groups heavily decorate the biopolymer [[lignin]].  Much interest has been shown in converting this abundant form of biomass into useful chemicals (aside from fuel).  One step in such processing is demethylation.
<ref>{{cite journal |doi=10.1016/j.checat.2022.07.005 |title=Expanding the repertoire of Rieske oxygenases for O-demethylations |date=2022 |last1=Schmidt |first1=Sandy |journal=Chem Catalysis |volume=2 |issue=8 |pages=1843–1845 }}</ref><ref name="boerjan">{{cite journal |author1=W. Boerjan |author2=J. Ralph |author3=M. Baucher |date=June 2003 |title=Lignin biosynthesis |journal=[[Annu. Rev. Plant Biol.]] |volume=54 |issue=1 |pages=519–549 |doi=10.1146/annurev.arplant.54.031902.134938 |pmid=14503002|url=https://biblio.ugent.be/publication/211742/file/4144786 }}</ref>  The demethylation of [[vanillin]], a derivative of lignin, requires {{Convert|250|C|F|abbr=|sp=us}} and strong base.<ref>{{OrgSynth |author=Irwin A. Pearl |year=1949 |title=Protocatechulic Acid |volume=29 |pages=85 |collvol=3 |collvolpages=745 |prep=CV3P0745}}</ref> [[Pulp and paper industry]] digests lignin using aqueous [[sodium sulfide]], which partially depolymerizes the lignin.  Delignification is accompanied by extensive O-demethylation, yielding [[methanethiol]], which is emitted by [[paper mill]]s as an air pollutant.<ref>{{cite journal |doi=10.1080/00022470.1962.10468107 |title=Odor ''and'' Fallout Control ''in a Kraft Pulp Mill'' |date=1962 |last1=Hansen |first1=G. A. |journal=Journal of the Air Pollution Control Association |volume=12 |issue=9 |pages=409–436 |pmid=13904415 }}</ref>