## 2 Results and Discussion
### Catalytic Activity  
Phenol, water, acetic acid, acetaldehyde, hydroxyacetone, d-glucose and 2-hydroxymethylfuran were mixed together and used as a model bio-oil to react with 1-octene/1-butanol at 120 \({}^{\circ}\)C for 3 h over each of the five catalysts: Cs\({}_{2.5}\)/K10, A15, A36, DX2 and SSA. Table 3 shows the 1-octene, 1-butanol and phenol conversions as well as the 1-octene isomerization and _O_-alkylation selectivities of these reactions [22]. 1-Octene conversions differed significantly over these catalysts and followed the order: SSA (\(\approx\)60%) \(>\) DX2 (40-50%) \(>\) A15 (27%) \(>\) A36 (14%) \(>\) Cs\({}_{2.5}\)/K10 (10%). Similar differences occurred for both phenol conversion and 1-octene isomerization. The phenol conversion was higher with SSA (64.1%) verses DX2 (37.3%), A15 (27.6%), A36 (6.1%) and Cs\({}_{2.5}\)/K10 (1.2%). The 1-octene isomerization activities of these five catalysts are 87.9% (SSA), 55.5% (DX2), 54.1% (A15), 13.5% (A36) and 1.9% (Cs\({}_{2.5}\)/K10). These follow the same order and show the higher activity of the SSA catalyst. Higher phenol conversion was accompanied by higher 1-octene isomerization activity and higher 1-octene conversions. SSA is the most active catalyst. This is because it is a stronger acid than the three resin sulfonic acids. Compared with the resin sulfonic acids ( \(\bigoplus\)C\({}_{6}\)H\({}_{4}\)-SO\({}_{3}\)H ), where the S atom has 3 O atoms attached, the S atom in SSA ( \(\langle\)SiO\({}_{2}\rangle\)-OSO\({}_{3}\)H ) has 4 O atoms attached. This causes the weaker basicity of -O-SO\({}_{3}^{\bigoplus}\)  verses that of Ph-SO\({}_{3}^{\bigoplus}\). Thus, SSA is the strongest acid. The stronger the acid, the more 1-octene protonation is favored. Hence, more octyl cations are generated. With the increase in octyl cation concentration, both phenol alkylation (phenolic oxygen attack on the carbocation) and 1-octene isomerization reaction (loss of proton from the carbocation) would speed up \begin{table}
\begin{tabular}{c c|c c} \hline  & **SSA** & \multicolumn{2}{c}{**Cs\({}_{2.5}\)/K10**} \\ \hline
**Absorption (cm\({}^{-1}\))** & **Assignment** & **Absorption (cm\({}^{-1}\))** & **Assignment** \\ \hline
3200–3500 & hydrogen bonded -OH & 1075 & P-O stretching \\
1178 & S=O symmetrical stretching & 1032 & Si-O in K10 clay \\
1000–1100 & Si-O-Si bridge stretching & 982 & terminal W=O \\
971 & Si-OH stretching & 886,790 & W-O-W vibrations \\
852, 886 & S-O stretching & & \\ \hline \end{tabular}
\end{table} 
Table 2: Characteristic IR absorptions for SSA and Cs\({}_{2.5}\)/K10 catalysts [22]. accompanied with faster consumption of 1-octene. This is consistent with higher phenol conversion and both 1-octene isomerization activity and conversion to other products with SSA. Stronger acids also promote both esterification and acetal formation rates. This can be observed from the higher 1-butanol conversion (97.4%) with SSA catalyst. Except for the modest 1-butanol conversion (68%) formed over Cs\({}_{2.5}\)/K10, 1-butanol conversions with the three resin sulfonic acids catalysts all exceeded 90%. Carboxylic acid esterifications and aldehyde/ketone acetal formation with 1-butanol are reversible or equilibrium reactions. The desirable forward reaction products like esters and acetals were produced accompanied by formation of water. That water and the original water present in bio-oil would inhibit the forward reactions, limiting further formation of more esters and acetals. Water removal by acid catalyzed hydration of 1-octene helped to shift these equilibria forming esters and acetals toward completion. Phenol alkylates (_C_- and _O_-) are desired because of their high octane number and high heating values [15]. The _O_-alkylated products are especially desirable because the acidic phenolic hydroxyl group is converted to an ether lowering product acidity and decreasing hydrophilicity. Moreover, _O_-alkylated phenol ethers are readily combusted. Except for Cs\({}_{2.5}\)/K10, all the catalysts gave high _O_-alkylation selectivity (>60%).