## 4 Types of Catalysts Used in Transesterification
### Nano-Catalysts
#### 4.5.2 Plant and Animal Origin Green Nanocatalysts
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \begin{tabular}{c} **Sr.** \\ **No.** \\ \end{tabular} & **Type of Catalyst** & \
\begin{tabular}{c} **Active** \\ **Metal/Functional** \\ **Group** \\ \end{tabular} & **Feedstock Oil** &
\begin{tabular}{c} **Biodiesel** \\ **Yield (\%)** \\ \end{tabular} & **Reusability of Catalyst** & **References** \\ \hline \multicolumn{6}{c}{**Montmorillonite clay catalyst and its derivatives**} \\ \hline \multirow{3}{*}{1} & KF/CaO impregnated & \multirow{3}{*}{KF/CaO} & \multirow{3}{*}{Soybean Oil} & \multirow{3}{*}{98} & 98\%, 91\% and 78\% in \\  & montmorillonite clay catalyst & & & & three consecutive rounds \\  & & & & & 83.78\%, 78.30\% and \\  & & Barium modified & \multirow{3}{*}{Ba} & \multirow{3}{*}{Waste Cooking Oil} & \multirow{3}{*}{83.38} & 21.50\% in three \\  & montmorillonite clay catalyst & & & & successive runs \\  & & Sulphonated phenyl silane & \multirow{3}{*}{Jatropha oil, Castor oil} & \multirow{3}{*}{98, 89.8} & 92\%, 85\% at seventh turn \\  & montmorillonite clay catalyst & & & & \\  & KOH montmorillonite K10 & & Palm oil & 98 & No reusability test \\  & & Zirconium & \multirow{3}{*}{K\({}_{2}\)CO\({}_{3}\)} & \multirow{3}{*}{Turnip oil} & \multirow{3}{*}{99.9} & 2 cycles (99.9\%) to 4 th \\  & clay catalyst & & & & & \\  & & & & & & \\  & & & & & & \\  & Cd-Mn montmorillonite & \multirow{3}{*}{Cd-Mn} & \multirow{3}{*}{_Prunus crasosides_ seed oil} & \multirow{3}{*}{85} & (88\%) in three consecutive \\  & clay catalyst & & & & turns then lowered & \\  & & & & & & \\  & Fe montmorillonite K-10 & FeCl\({}_{3}\) Fe\({}^{3+}\) & Waste cooking oil & 92.74 & No reusability test & [98] \\ \hline \hline \multicolumn{6}{c}{**Sepiolite clay catalyst and its derivatives**} \\ \hline \multirow{3}{*}{8} & NaOH impregnated sepiolite & NaOH & Canola oil & 80.93 & No reusability test & [99] \\  & Extruded catalyst (K\({}_{2}\)CO\({}_{3}\) & & & Yield decreased from 1, \\  & and sepiolite) & K\({}_{2}\)CO\({}_{3}\) & & & 2 cycles (99.9\%) to 4 th \\  & & & & & cycle (26\%) & \\  & & & & & & Recycled via external \\
10 & K\({}_{2}\)CO\({}_{3}\)/\(\gamma\)-Al\({}_{2}\)O\({}_{3}\)/sepiolite & & Waste cooking oil & 88 & magnetic field, \\  & & & & & guaranteeing reusability \\  & & & & & to several turns \\
11 & K\({}_{2}\)CO\({}_{3}\) polygorskite & & Palm Oil & 97 & Up to 8 cycles (82\%) & [102] \\
12 & KF/CaO supported polygorskite & KF/CaO & Soybean oil & 97.9 & Up to 10 cycles (91.5\%) & [103] \\ \hline \multicolumn{6}{c}{**Kaolinite clay catalyst and its derivatives**} \\ \hline \multirow{3}{*}{13} & HY zeolite & - & Oleic acid & 85 & No reusability test & [104] \\  & NaOH Kaolin & NaOH & Triolein & 92.8 & Three consecutive time & [105] \\  & Phosphoric acid activated & & African pear seed oil & 70–80 & No reusability test & [106] \\  & Kaolin catalyst & & & & Reusability was checked & \\  & & & & & with three & \\  & & & & & solventsDistilled water & \\  & & & & & 94.76\% = 92.55 \(\times\) 87.88\% \textgreater{} \\
16 & K\({}^{*}\) trapped kaolinite & K\({}^{*}\) & Waste cooking oil & 94.76 & 80.5\% \textgreater{} 76.77\% Methanol & [107] \\  & & & & & 94.76\% \textgreater{} 94.34 \textgreater{} 91.66\% \textgreater{} \\  & & & & & 87.77\% \textgreater{}83.33\%,Acetone & \\  & & & & & 94.76\% \textgreater{}94.45\textgreater{} 92.4\% \textgreater{} \\  & & & & & 85.2\% \textgreater{}80.66\% & \\
17 & Ce-Kaoline clay catalyst & Ce & Cotton seed oil & 91 & Upt0 4 cycles (74\%) & [108] \\
18 & KF modified Kaolinite & KF & Jatropha oil & - & No reusability test & [109] \\  & clay catalyst & & & & & \\
19 & CaO/Kaoline Catalyst & CaO & Coconut oil & - & No reusability test & [110] \\ \hline \multicolumn{6}{c}{**Bentonite clay catalyst and its derivatives**} \\ \hline \multirow{3}{*}{20} & Graphene oxide/Bentonite & \multirow{3}{*}{NaOH GO} & \multirow{3}{*}{Oleic acid, Rapeseed} & \multirow{3}{*}{98.5} & Significant decrease in \\  & Bi-functional & & graphene oxide & & yield after two cycles \\  & heterogeneous catalyst & & & & & \\  & Bentonite/Zeolite & Na\({}^{+}\) & Palm oil & 98 & Reusable up to 8 cycles & [112] \\  & P-composite catalyst & & & & \\  & Heteropoly phosphomolybtic & \multirow{3}{*}{H\({}_{3}\)PMo\({}_{12}\)O\({}_{40}\)} & \multirow{3}{*}{Palm oil waste} & \multirow{3}{*}{93} & Reusable up to 3 cycles & [113] \\  & impregnated bentonite & & (HMnO) & & & \\  & Sodium methoxide & & & & & \\  & supported bentonite & & CH\({}_{3}\)ONa & Waste flower oil & 94.33 & After consecutive (80\%) & [114] \\ \hline \hline \end{tabular}
\end{table}