added subsecjection for results
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56
main.tex
56
main.tex
@@ -127,6 +127,62 @@ The heterogeneous mixture was subsequently clarified via filtration through a ce
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\end{table}
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\subsection{\ce{H2SO4} Catalyzed Tandem Hydrolysis--Esterification}
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The conversion of ASA to methyl salicylate proceeds via a one-pot tandem sequence (Scheme~\ref{sch:mechanism}). Concentrated \ce{H2SO4} serves as a Brønsted acid catalyst, activating the carbonyl groups toward nucleophilic attack by methanol, and as a dehydrating agent to shift the equilibrium.
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\begin{scheme}[H]
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\centering
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\small
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\setchemfig{atom sep=2.0em, compound sep=5em, nodesep=2pt}
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% Wrapper to ensure vertical alignment of the three main components
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\begin{tabular}{ccc}
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\chemname{
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\chemfig{*6(-=-(-O-[:-30](=[:-90]O)-[:+30]CH_3)=([:60]-[:90](=[:150]O)-[:30]OH)-=)}
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}{\footnotesize Acetylsalicylic Acid}
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&
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\parbox{2.5cm}{\centering $\xrightarrow[\Delta]{\ce{CH3OH, H2SO4}}$}
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&
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\chemname{
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\chemfig{*6(-=-(-OH)=([:60]-[:90](=[:150]O)-[:30]O-[:+90]CH_3)-=)}
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}{\footnotesize Methyl Salicylate}
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\end{tabular}
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\vspace{1.5em}
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\caption{Tandem deacetylation and Fischer esterification sequence.}
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\label{sch:mechanism}
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\end{scheme}
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The transformation encompasses two concurrent equilibrium-driven processes:
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\begin{enumerate}
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\item \textbf{Acid-Catalyzed Solvolysis:} The acetoxy group undergoes transesterification with methanol to yield salicylic acid and methyl acetate (Eq~\ref{eq:solvolysis}).
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\item \textbf{Fischer Esterification:} The carboxylic acid is esterified by the methanol solvent (Eq~\ref{eq:fischer}).
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\end{enumerate}
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\begin{equation}
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\ce{R-OCOCH3 + CH3OH <=>[H+] R-OH + CH3COOCH3}
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\label{eq:solvolysis}
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\end{equation}
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\begin{equation}
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\ce{Ar-COOH + CH3OH <=>[H+] Ar-COOCH3 + H2O}
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\label{eq:fischer}
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\end{equation}
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To drive the reaction toward the methyl salicylate product, a substantial stoichiometric excess of methanol was employed, utilizing Le Chatelier's principle to overcome the reversible nature of the esterification.
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\subsection{Work-up and Purification}
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Following reflux, the reaction was quenched in ice-cold distilled water. Methyl salicylate ($\rho \approx 1.17$ g/mL) was isolated as the organic phase via liquid--liquid extraction. Residual acidic species (\ce{H2SO4}, \ce{CH3COOH}) were neutralized using saturated \ce{NaHCO3}:
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\begin{equation}
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\ce{H2SO4(aq) + 2NaHCO3(aq) -> Na2SO4(aq) + 2CO2(g) + 2H2O(l)}
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\end{equation}
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The organic extract was dried over anhydrous \ce{MgSO4} and filtered to yield the pure essential oil.
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\subsection{Outline}
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The document layout should follow the style of the journal concerned. Where
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