*3.3. Catalytic Ketonisation*

Acetic acid ketonisation was performed in a bespoke continuous flow packed-bed reactor with online gas chromatography (GC) analysis. The reactor comprised a 1 cm o.d., quartz tube, within which the catalyst bed was placed centrally and retained by quartz wool plugs. A constant catalyst bed volume of 4 cm<sup>3</sup> was used in all experiments, comprised of 200 mg of catalyst diluted with fused silica granules. The reactor tube was positioned in a temperature-programmable furnace with a thermocouple placed in contact with the catalyst bed. Acetic acid (Sigma-Aldrich, UK, ACS reagen<sup>t</sup> ≥ 99.7%) was fed in a down-flow fashion into the reactor using an Agilent 1260 Infinity Isocratic Pump (Agilent, UK) and N2 as the carrier gas (50 mL·min−1). All reactor lines were heated to 130 ◦C to prevent condensation, and a 1 cm diameter metal tube packed with fused silica granules was used to ensure acetic acid vaporisation before the reactor. Products were analysed online by a Varian 3800 GC (Varian, UK) with heated gas-sampling valve, equipped with a BR-Q PLOT column (30 m × 0.53 mm i.d.,). Acetone and acetic acid were detected using a flame ionisation detector (FID). The GC was calibrated for acetic acid and acetone by triplicate injections of 50 μl standard solutions through a split/splitless injector. Acetic acid conversion and selectivity were calculated according to Equations (1) and (2).

$$\text{Conversion} = \frac{\text{n}\_{\text{AcOH}\_0} - \text{n}\_{\text{AcOH}}}{\text{n}\_{\text{AcOH}\_0}} \times 100\tag{1}$$

$$\text{Selocity} = \frac{2 \times \text{n}\_{\text{Acetone}}}{\text{n}\_{\text{AcOH}\_0} - \text{n}\_{\text{AcOH}}} \times 100\tag{2}$$

where nAcOH0 is the initial moles of acetic acid, nAcOH is the final moles acetic acid and nAcetone represents the moles of produced as acetone. Acetone was the primary product over all catalysts. No acetic acid conversion was observed in the absence of a catalyst.
