Don't even dream of competing against the giants on mass-produced chemicals. If you really want to produce by yourself, find niches too small for the big companies.
Could
deuteriated products be a niche small enough? Standard suppliers already propose them, but maybe some compounds are missing?
Chiral compounds? If I get it properly, a few acids, amines and chromatography solids serve to purify the varied produced compounds (=drugs). Maybe the users here could tell if they want some such ones and don't find them, or not pure enough, or with too long delivery times?
I suggested here a possible hypothetic method to separate enantiomers
http://www.chemicalforums.com/index.php?topic=65386.0and shorter there hence quickly read but without ChemicalForum's precious comments
http://www.scienceforums.net/topic/79159-adapt-czochralski-to-chiral-separation/but beware it's not tried, needs developments, and of course is doubtful as anything new.
Cooling liquids for the electronics industry. They must insulate, be thin, noncorrosive and nontoxic, preferably nonflammable, and if they cool it's better. Presently fluorocarbons made by big companies, but fluorocarbons will be banned. I suppose branched alkanes can replace them. Maybe one can purify Diesel oil very much, more so than to obtain RP-1, but my guess is that a synthetic compound will be preferred, something like farnesane or phytane if one can produce them in significant amounts.
Better transformer oil? Presently a very purified mineral oil, but a synthetic compound may improve, again like farnesane or phytane (free of pristane!). Purity could extend its life expectancy or its insulating capability. Less easy than the cooling liquid, as it must be cheaper.
Greases and oils for ultrahigh vacuum? Presently they're silicones and fluorosilicones, for the low vapour pressure; maybe some alkane suits better. Again like phytane, or an even heavier one. Kilogram price isn't a worry there. A frew branched C
40 and even heavier are liquid at room temperature; that promises a low vapour pressure.
I've put my thoughts about low-freezing alkanes there
http://www.chemicalforums.com/index.php?topic=56069beware that all I imagined about their synthesis is probably nonsense (and forget about the amines in these uses!). I trust the melting, flash, boiling points there.