Partial and Total Solvent-Free Limonene’s Hydrogenation: Metals, Supports, Pressure, and Water Effects

Table 2

Hydrogenation of limonene over Pt.

Pressure (MPa)	Support	H2O	Conversion (%)	Menthene/menthane (%)	Cis/trans menthane (%)	Time (h)	TOF (h^−1)^a	Cymene (%)
2.75	Carbon^b	—	100	0/100	37/63	2	143	0
		100 µL	100	0/100	45/55	4	71.5	0
		5 mL	100	0/100	36/64	3	95.3	0
		—	100	96/4	48/52	2	143	0
		100 µL	100	100/0	—	2	143	0
		5 mL	86	100/0	—	24	10	0
	Silica^c	—	100	98/2	39/61	2	143	0
		100 µL	100	97/3	31/69	2	143	0
		5 mL	100	86/14	49/51	4	71.5	0
0.275	Carbon^b	—	100	67/33	36/64	24	12	0
		100 µL	100	70/30	43/57	6	48	0
		5 mL	61	100/0	—	6	29	0
		—	73	66/7	49/51	2	104	0
		100 µL	100	94/6	41/59	6	48	0
		5 mL	55	100/0	—	24	6.5	0
	Silica^c	—	100	93/7	45/55	4	71.5	0
		100 µL	100	86/14	47/53	6	48	0
		5 mL	3	100/0	—	24	3.5	0

Experimental conditions: pure limonene, the catalyst, and room temperature. ^aTurnover frequency (TOF) = number of moles of consumed limonene/(mole of catalyst) time of reaction; ^b5% wt; ^c1% wt.