Acetic Acid, Diacetin & Triacetin By: S. Afsari Quaternary Solubility of in Supercritical Carbon Dioxide Superadvisor: Dr. Ghaziaskar

Contents o oIntroduction o oSupercritical Region o oSupercritical fluids and CO 2 as a SF. o oAdvantages of Supercritical Sys. o oFactors effecting on supercritical solubility o oApparatus o oSFE systems o oACAC and Glycerol Acetyls in supercritical systems o oSolubility measurements in ScCO 2 and possible separation techniques

Why Glycerol Acetyls?

Transesterification of vegetable oils + 3 HOCH 3 NaOH or KOH Catalyst +

Glycerol acetylation

Diacetin Triacetin Structure Formula Molecular weight Melting point -30 ºC Boiling point 259 ºC Structure Formula Molecular weight Melting point -30 ºC Boiling point259 ºC

Supercritical Region C T scco21

Supercritical Fluids Sc FluidCritical T (ºC) Critical P (bar) Critical ρ (g/mL) (CO 2 ) (H 2 O) (N 2 O) (NH 3 ) (C 4 H 10 ) (SF 6 ) (Xe) (CH 2 F 2 ) (CH 4 ) (C 3 H 8 ) (C 2 H 6 O) (C 6 H 6 ) ) Low critical T 2)Cheap 3) available 3) Inexplosive 4) Nontoxic Х Х Х

CO 2 Phase Diagram

Gas like liquid like Ability of controlling Solubility High diffusion Low viscosity Easy separation of solvent from solute

Factors Effecting Solubility in Supercritical Fluids Pressure Temperature Solute Structure Solvent Structure Sample Matrix Hildebrand Parameter:

Factors Effecting Solubility in Supercritical Fluids Pressure Temperature Solute Structure Solvent Structure Sample Matrix 40ºC 60ºC

Factors Effecting Solubility in Supercritical Fluids Pressure Temperature Solute Structure Solvent Structure Sample Matrix 1)Solute Structure 2)Solute Vapor pressure 3)Solute-Solvent interactions

Factors Effecting Solubility in Supercritical Fluids Pressure Temperature Solute Structure Solvent Structure Sample Matrix ScF Density (g/ml)Solubility (mole fraction X 100) Supercritical Fluid Naphthalene

Factors Effecting Solubility in Supercritical Fluids Pressure Temperature Solute Structure Solvent Structure Sample Matrix 1)Chemical properties 2)Physical properties

Apparatus Gas Meter

Introduction

2 port cylindrical cells

Apparatus Gas Meter

Back Pressure Adjuster

Apparatus Gas Meter

Sampling Collection solvent Solute

Apparatus Gas Meter

SFE Systems On-line On-line Off-line Off-line Different possible analyzing methods Simple & practical separation Higher sensitivity  Lower repeatability Higher repeatability Lower solvent consumption Lower time consuming procedure  Fluctuations in flow rate

Solubility Gas meter: V, T Gas meter: V, T Weighting Weighting GC GC Mole fraction: g/L in CO 2

Sample: Solvent: Et-OH ACAC DAG TAG :89% :9% :6%

y×100 Pressure (bar) System Stability Checking

CO 2 Volume (L) W (mg) Purge Test

Effective Parameters on Solubility in ScCO 2 Temperature Pressure Flow Rate Weight of sample Weight of Sample ACAC y×100 CO 2 Volume (L)

Weight of Sample TAG y×100 CO 2 Volume (L)

Weight of Sample DAG y×100 CO 2 Volume (L)

Effective Parameters on Solubility in ScCO 2 Temperature Pressure Flow Rate Weight of sample Weight of Sample y×100 CO 2 Volume (L)

Effective Parameters on Solubility in ScCO 2 Temperature Pressure Flow RateWeight of sample Ө (ºC): 30,40,60,75 P (bar): 70,100,120,140,160,180 y×100 Pressure (bar) 40ºC 60ºC 75ºC ACAC

TAG Ө: 40ºC, P: 70 bar Ө: 60ºC, P: 70 bar Ө: 75ºC, P: 70 bar Ө: 75ºC, P: 100 bar y×100 Pressure (bar) 40ºC 60ºC 75ºC

DAG Ө: 40ºC, P: 70 bar Ө: 60ºC, P: 70 bar Ө: 60ºC, P: 100 bar Ө: 75ºC, P: 70 bar Ө: 75ºC, P: 100 bar y×100 Pressure (bar) 40ºC 60ºC 75ºC

Separation ACAC, DAG, TAG α%α% Pressure (bar)

Separation of ACAC Expanded CO2 (L) Elapsed time (min) Extracted ACAC (mg) Extracted ACAC (%) Ө: 60ºC P: 70 bar

Separation of ACAC Expanded CO2 (L) Elapsed time (min) Extracted ACAC (mg) Extracted ACAC (%) Ө: 60ºC P: 70 bar Et-OH ACAC n-hexanol

Separation of ACAC Expanded CO2 (L) Elapsed time (min) Extracted ACAC (mg) Extracted ACAC (%) Ө: 75ºC P: 100 bar

Separation TAG & DAG Ө: 40ºC, P: 70 bar Ө: 60ºC, P: 70 bar Ө: 75ºC, P: 70 bar Ө: 75ºC, P: 100 bar TAG Ө: 40ºC, P: 70 bar Ө: 60ºC, P: 70 bar Ө: 60ºC, P: 100 bar Ө: 75ºC, P: 70 bar Ө: 75ºC, P: 100 bar DAG Ө=60 ºC, P=70 bar ACAC Ө=60 ºC, P=100 bar TAG 1)Incomplete extraction 2)Low efficiency

Separation of ACAC under Subcritical Situation ?

Factors Effecting Solubility in Supercritical Fluids Pressure Solute Structure Solvent Structure Sample Matrix 1)Chemical properties 2)Physical properties Binary and Quaternary Solubility of Acetic Acid y×100 Pressure (bar) Binary Quaternary

Solvent Attributes of ScCO 2 CO2CO2 C O O C CH 3 OH O C CH 3 OH O

Factors Effecting Solubility in Supercritical Fluids Pressure Solute Structure Solvent Structure Sample Matrix 1)Chemical properties 2)Physical properties y×100 Pressure (bar) Ө= 40ºC

Factors Effecting Solubility in Supercritical Fluids Pressure Solute Structure Solvent Structure Sample Matrix 1)Chemical properties 2)Physical properties Ө= 75ºC y×100 Pressure (bar)

Bartle Equation y: Solubility (mole fraction) T: temperature (K) ρ: CO2 density in P & T ( ) y x b m

Experimental Solubility Correlation ACAC ACAC DAG DAG TAG TAG Ө: 40ºC, 75ºC Ө: 40ºC, 75ºC P: bar P: bar Ө: 60ºC Ө: 60ºC P: bar P: bar ρ (g/L) Pressure (bar)

Experimental Solubility Correlation ACAC Ln(yP/P ref ) ρ-ρ ref

Experimental Solubility Correlation ACAC y=0.0044x Line Eq.c ( )b (K)a Ln(yP/P ref ) ρ-ρ ref

Experimental Solubility Correlation y=0.0044x Line Eq.c ( )b (K)a ACAC 8.0y=0.0048x AARD%Line Eq.c ( )b (K)a DAG 12.0y=0.0049x AARD%Line Eq.c ( )b (K)a TAG