ethyl 2-ethylhexanoate (orris/iris scent, trade name Irotyl)

151,3 g = 1,05 mol 2-ethylhexanoic acid (for those who are from CZ you can buy it very cheap in fichema.cz)
+
ethanol 3 fold excess 3,15 mol * 46,07 g/mol = 145,12 g 100% = 152,76 g 95%
+
5 ml 96% H2SO4 (catalyst) added dropwise while stirring

5 hours rfx

cooled quickly to room temperature in ice cold water bath

washed with 750 ml of cold water in separatory funnel
washed with saturated NaHCO3 solution until no more CO2 effervescence (4x 150 ml), thousands of vigorous shakes, lasted for more than 1 hour !
washed with 500 ml of cold water, it formed a milky like emulsion, so 100 ml of saturated NaCl solution was added to facilitate layers separation
bottom layers always discarded and upper organic layer kept

so far 142,7 g of ester 172,26 g/mol (0,83 mol)

put into a freezer to -18 C for half a day to freeze out some water and further dried with anhydrous Na2SO4 for 1 hour

distilled from 250 ml RBF using oil bath and air condenser
forerun 10 ml which still drove out some water present and it was necessary to replace distillation head and condenser with new clean dry ones, main fraction collected 184-186 C with yield 121,8 g (0,707 mol, 67 %), remainder in the distillation flask 10 ml

I'm unable to assign the scent more precisely, it reminds me a kind of unknown pleasant flower/blossom and is much weaker than usual fruity scents of shorter chain esters. People skilled in scents/perfumery describe it as orris/iris which I have never smelled yet (or if I did I do not remember).

http://www.thegoodscentscompany.com/data/rw1023191.html

https://www.kaochemicals-eu.com/products/ethyl-2-ethylcapron...
CHEMICAL NAME Ethyl-2-ethylcapronate
TRADE NAME IROTYL®
CAS 2983-37-1



rfx for 5 hours (acid:alcohol = 1:3, cat. H2SO4)





last washing formed an emulsion, it was necessary to add solution of NaCl to break it and force to separate layers





main fraction collected 184-186 C, at the end the T dropped down due to decreased flow of vapor around the thermometer stem, air condenser used according the high T (vacuum distillation could be performed instead)