Dodecyl acetate

A mixture of n-alkanes (C₈—C₂₀) dissolved in hexane for retention index determination was purchased from Fluka (Buchs, Switzerland). Reference compounds, (E)-2-hexen-1-ol (> 96%), (E)-2-octen-1-ol (> 97%), 1-decyne (> 98%), 1-dodecene (≥ 99%), (E,E)-2,4-hexadienal (≥ 97%), 2-cyclohexen-1-ol (> 95%), (E)-2-hexenal (≥ 99%), (E)-2-octenal (≥ 95%), 4-tert-butylcyclohexyl acetate (mixture of E and Z, > 98%), allyl cyclohexanepropionate (≥ 98%), cyclopentanemethanol (≥ 98%), cyclopentanol (≥ 99%), cyclopentanone (≥ 99%), decanal (≥ 98%), 1-dodecanol (≥ 98%), dodecyl acetate (> 97%), hexyl acetate (≥ 99%), hexyl salicylate (≥ 99%), limonene (> 97%), nonanal (≥ 97%), octyl acetate (≥ 99%), p-cymene (> 99%), 1-tridecanol (≥ 99%), and α-hexylcinnamaldehyde (≥ 95%) were supplied by Sigma Aldrich (Munich, Germany).

Lavandulyl acetate (LA), lavandulyl methylbutanoate (LMB), and neryl methylbutanoate (NMB) were synthesized (AD, Inc., Andong, Korea) (S1 Fig). Briefly, LA and LMB were synthesized from the precursor, lavandulol (≥ 90%, Sigma-Aldrich Korea, Seoul, Korea) in dichloromethane, which was reacted with acetyl chloride to yield LA, and reacted with isovaleryl chloride (≥ 98%, Sigma-Aldrich Korea, Seoul, Korea) to yield LMB, respectively, under the catalytic activity of trimethylamine. NMB was used in a reaction with geraniol (> 98%, Sigma-Aldrich Korea) and isovaleryl chloride under the catalytic activity of trimethylamine. All products were extracted with ethyl acetate and produced 70 ~ 75% yields. The purity of the compounds was analyzed by gas chromatography (8860 GC, Agilent, Santa Clara, CA, USA) with a DB-1 column (15 m × 0.350 mm, Agilent), an oven temperature of 280°C, and a flow rate of 1.0 mL/min, and was determined to be 98.1% for LA, 98.1% for LMB, and 99.3% for NMB. All synthesized products were in the form of a racemic mixture. Two alarm pheromone components (decyl acetate and dodecyl acetate, 98%) were purchased from Sigma-Aldrich Korea and dissolved in hexane to prepare different concentrations.

The aromatic amines used (Table 1) were purchased from Sigma-Aldrich (Steinheim, Germany), except for 4-chloro-2-methylaniline and 3-chloro-2,6-dimethylaniline which were purchased from Fluka (Darmstadt, Germany) and Alfa Aesar (Karlsruhe, Germany), respectively.Table 1

List of aromatic amines used with their corresponding abbreviation, structure, CAS-number, pKa value of the corresponding anilinium ion, log P value for the neutral compound, and purity

For the LPME optimization, the solvents dodecyl acetate (97%, abbreviated DDA), undecane (≥ 99%, UD), and dihexylether (97%, DHE) were purchased from Sigma-Aldrich, and 2-octanone (98%, 2O) was purchased from Alfa Aesar. Concentrated hydrochloric acid (ACS reagent, 37%, HCl) and sodium hydroxide (98%, NaOH) were purchased from Bernd Kraft (Duisburg, Germany).
During the derivatization, hydriodic acid (ACS reagent, unstabilized, 55%), sodium nitrite (99%), and Alizarin red S (98%) obtained from Sigma-Aldrich, and sodium sulfite (puriss. p.a., ACS reagent, RT, ≥ 98%) and sulfamic acid (T, ≥ 99%) from Fluka were used.
Diethyl ether (DEE) and HPLC grade methanol were purchased from Fisher Scientific (Schwerte, Germany), and ultrapure water was obtained from a PureLab Ultra water system from ELGA LabWater (Celle, Germany).