\documentclass[12pt,border=1pt,crop,multi=false,tikz,class=scrartcl]{standalone}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage{chemfig,chemmacros,chemformula}
\usepackage{lmodern}
\usetikzlibrary{decorations.pathmorphing}
 
\chemsetup[chemformula]{font-shape=sf,format=\sffamily}
\chemsetup[option]{circletype=math}
\renewcommand*{\familydefault}{\sfdefault}
\renewcommand*\printatom[1]{\ensuremath{\mathsf{#1}}}
\setatomsep{1.8em}
\setdoublesep{.6ex}
\setarrowdefault{,.8,semithick}
\setbondstyle{thick}
 
\makeatother
\begin{document}
\definesubmol\nobond{-[,0.2,,,draw=none]}
\schemestart
	\chemfig{PPO-[::30]-[2]=^[::60](-[::60])-[2]-[::-60]-[::-60]=^[::60](-[2])-[::-60]-[6]-[::-60]=^[6](-[::60])-[::-60]}
    \arrow
    \chemfig{@{d21}\fmch OPP-[::30,.2,,,draw=none]-[2,,,,draw=none](-[@{d24}::-60](!\nobond\fpch))=_[@{d23}::60]@{d22}(-[::60])-[2]-[::-60]-[::-60]=^[::60](-[2])-[::-60]-[6]-[::-60]=^[6](-[::60])-[::-60]}
    \arrow
    \chemfig{@{d32}OPP-[@{d31}2,1.2,1](-[:-150])(-[@{d34}:-30]=^[@{d33}::60]@{d36})-[2]-[::-60]-[::-60]=^[@{d35}::60](-[2])-[::-60]-[6]-[::-60]=^[6](-[::60])-[::-60]}
    \arrow
    \chemfig{-[::30,.2,,,draw=none]-[2,,,,draw=none](-[::-60](<:[6]H)(<[@{d41}:20]H)-[2](<:[2]H))=_[::60](-[::60])-[2]-[::-60]-[::-60]-[::60]@{d42}(!\nobond\fpch)(-[2])-[::-60]-[6]-[::-60]=^[6](-[::60])-[::-60]}
    \arrow[-110]
    \chemfig{-[::30,.2,,,draw=none]-[2,,,,draw=none](-[::-60]@{d52}(<:[6]H)(!\nobond\fpch)-[2](<:[2]H))=_[::60](-[::60])-[2]-[::-60]-[::-60]-[::60](<[:20]H)(<:[2])-[::-60]-[6]-[::-60]=_[@{d51}6](-[::60])-[::-60]}
    \arrow[180]
    \chemfig{-[::30,.2,,,draw=none]-[2,,,,draw=none](-[::-60](<:[6]H)-[2](<:[2]H))=_[::60](-[::60])-[2]-[::-60]-[::-60]-[::60](<[:20]H)(<:[2])-[::-60]-[6]-[::-60](-[::-60])<[6](-[6,.4,,,draw=none]\fpch)(-[@{d62}::60]-[@{d61}::60]H)-[::-60]}
    \arrow[180]
    \chemfig{-[::30,.2,,,draw=none]-[2,,,,draw=none](-[::-60](<:[6]H)-[2](<:[2]H))=_[::60](-[::60])-[2]-[::-60]-[::-60]-[::60](<[:20]H)(<:[2])-[::-60]-[6]-[::-60](-[::-60])<[6](=[::60])-[::-60]}
    \arrow[-90]
    \chemfig{-[::30,.2,,,draw=none]-[2,,,,draw=none](-[::-60](<:[6]H)-[2](<:[2]H))=_[::60](-[::60])-[2]-[::-60]-[::-60]-[::60](<[:20]H)(<:[2])-[::-60]-[6]-[::-60](-[::-60])<[6](=[::60])-[::-60]-[::-60]HO}
    \arrow[,,dashed]
    \chemfig{-[::30,.2,,,draw=none]-[2,,,,draw=none](-[::-60](<:[6]H)-[2](<:[2]H))=_[::60](-[::60])-[2]-[::-60]-[::-60]-[::60](<[:20]H)(<:[2])-[::-60]-[6]-[::-60](-[::-60])<[6](=[::60])-[::-60]=_[::-60]O}
    \arrow[,,dashed]
    \chemfig{-[::30,.2,,,draw=none]-[2,,,,draw=none](-[::-60](<:[6]H)-[2](<:[2]H))=_[::60](-[::60])-[2]-[::-60]-[::-60]-[::60](<[:20]H)(<:[2])-[::-60]-[6]-[::-60](-[::-60])<[6](=[::60])-[::-60](-[6]OH)=[::-60]O}
    \arrow(@c8--)[-90,,dashed]
    \chemfig{-[::30,.2,,,draw=none]-[2,,,,draw=none](-[::-60](<:[6]H)-[2](<:[2]H))=_[::60](-[::60])-[2]-[::-60]-[::-60]-[::60](<[:20]H)(<:[2])-[::-60]-[6]-[::-60](-[::-60])<[6](<[::60])-[::-60]-[::-65]HO}
    \arrow(@c9--)[-90,,dashed]
    \chemfig{-[::30,.2,,,draw=none]-[2,,,,draw=none](-[::-60](<:[6]H)-[2](<:[2]H))=_[::60](-[::60])-[2]-[::-60]-[::-60]-[::60](<[:20]H)(<:[2])-[::-60]-[6]-[::-60](-[::-60])<[6](<[::60])-[::-60]=_[::-60]O}
    \arrow(@c10--)[-90,.6,dashed]
    \chemfig{@{d132}O=[@{d131}]@{d134}O-[::30,.7,,,draw=none]-[2,,,,draw=none](-[::-60](<:[6]H)-[2](<:[2]H))=_[@{d133}::60](-[::60])-[2]-[::-60]-[::-60]-[::60](<[:20]H)(<:[2])-[::-60]-[6]-[::-60](-[::-60])<[6](=[::60])-[::-60](-[6]OH)=[::-60]O}
    \arrow[-55,.7]
    \chemfig{*6((-[4])(<:[:-135]O-[::60]OH)--(*6(-(<(<[::60])-[::-60](-[::60]OH)=[::-60]O)---(<:[2])(<[:20]H)-))(<:[6]H)-(<:[2]H)---) }
    \arrow[180]
    \subscheme{
    	\chemfig{H_2O}
        \arrow[-30,.1,draw=none]
    	\chemfig{*6((-[@{d172}4])(<:[:-135]@{d174}O-[@{d175}::60]@{d176}OH)-[@{d173}]-(*6(-(<(<[::60])-[::-60](-[::60]OH)=[::-60]O)---(<:[2])(<[:20]H)-))----) }
    }
    \arrow[180]
    \chemfig{[:-25.71]*7((-[::-120])(-OH)-O-=(*6(-(<(<[::60])-[::-60](-[::60]OH)=[::-60]O)---(<:[2])(<[:20]H)-))-(<:[2]H)---) }
    \arrow[180]
    \chemfig{-[:30](=[::60]O)-[::-60]-[::60]-[::-60](*6(-(-=^[::60]O)-(<(<[::60])-[::-60]HO_2C)---(<:[2])(<[:20]H)-))<:[2]H}
    \arrow{->[*0{\ch{O2}}]}[-90]
    \chemfig{-[:30]@{d202}(=[::60]O)-[::-60]-[::60]-[::-60](*6(-(-[:150]H|@{d201}O|O)(-=^[::60]O)-(<(<[::60])-[::-60]HO_2C)---(<:[2])(<[:20]H)-))<:[2]H}
    \arrow[,1]
    \chemfig{[:-25.71]*7((-[::-120]H|@{d211}O)(-)(<:[:20]O?)-[,,,,draw=none]-[,,,,draw=none]@{d212}(=^[@{d213}6]O)-(<:[180]O?)(*6(-(<(<[::60])-[::-60]HO_2|@{d214}C)---(<:[2])(<[:20]H)-))-(<:[2]H)---) }
    \arrow[,1]
    \chemfig{[:-25.71]*7((<)(<:[:20]O?[a])-O-(<:[6]O?[b])-(<:[180]O?[a])(*6(-(<(<[::60])-[::-60]?[b]=[::60]O)---(<:[2])(<[:20]H)-))-(<:[2]H)---) }
    \chemmove[-stealth, shorten >=2pt, shorten <=2pt]{
    	\draw (d21) .. controls +(north west:12mm) and +(north west:5mm) .. (d22);
        \draw (d23) .. controls +(north:5mm) and +(north:5mm) .. (d24);
        \draw (d31) .. controls +(west:5mm) and +(north west:5mm) .. (d32);
        \draw (d33) .. controls +(north:5mm) and +(north:5mm) .. (d34);
        \draw (d35) .. controls +(south:5mm) and +(north east:5mm) .. (d36);
        \draw (d41) .. controls +(north:5mm) and +(south:5mm) .. (d42);
        \draw (d51) .. controls +(west:5mm) and +(south east:5mm) .. (d52);
        \draw (d61) .. controls +(north:5mm) and +(north east:5mm) .. (d62);
        \draw (d131) .. controls +(north:5mm) and +(north:5mm) .. (d132);
        \draw (d133) .. controls +(south west:5mm) and +(north:5mm) .. (d134);
        \draw (c16) .. controls +(north east:15mm) and +(north:5mm) .. (d172);
        \draw (d173) .. controls +(south:5mm) and +(east:5mm) .. (d174);
        \draw (d175) .. controls +(west:5mm) and +(west:5mm) .. (d176);
        \draw (d201) .. controls +(south:5mm) and +(south:5mm) .. (d202);
        \draw (d211) .. controls +(south:5mm) and +(west:5mm) .. (d212);
        \draw (d213) .. controls +(east:5mm) and +(north:5mm) .. (d214);
    }
\schemestop
\end{document}