Environmentally Benign Neem Biodiesel Synthesis Using Nano-Zn-Mg-Al Hydrotalcite as Solid Base Catalysts

Table 1

Chemical composition analysis and physicochemical properties of Zn-Mg-Al hydrotalcites.

Catalysts	Theoretical ratio; Zn/Mg/Al	Experimental ratio^a; Zn/Mg/Al	Unit cell parameters (Å)			BET surface area (m^2/g)^b
			HT-1	2 : 2 : 1	1.96/1.89/1		3.042	22.73	7.31	166.4
HT-2	2 : 3 : 1	1.93/1.98/1	3.058	22.89	7.57	188.6
HT-3	3 : 3 : 1	3.02/2.98/1	3.063	22.95	7.72	220.8
HT-4	3 : 4 : 1	2.85/4.08/1	3.088	23.59	7.94	208.4

^aExperimental Mg-Zn-Al atomic ratios in the synthesized catalyst determined by EPMA.
^bBET surface area calcined at 500°C/8 h.