Partitioning of six printing ink solvents in high fat cookies and in the major fatty components, soybean oil and chocolate liquor, was studied by headspace analyses by gas chromatography. Solvents were ethyl acetate, hexane, isopropanol, methyl cellosolve, methyl ethyl ketone and toluene. The order of solvent partition coefficient magnitude between the target materials and air was soybean oil > chocolate liquor z cookies. Partition coefficients over the range from 1 to 200 ppm solvent in the target materials were constant, although some evidence of deviation at the lowest concentrations was found.
A permeation cell method was developed for the determination of transmission rates of organic vapors through flexible packaging materials. The permeation rates at 23°C of some compounds for several composite films at 0% and 75% relative humidity (RH) indicated that the polyethylene vinyl alcohol and nylon combinations exhibited superior barrier properties even at elevated RH, provided that moisture barrier films were present in the laminate construction.
The use of biomass-based ethanol as fuel depends on developing economical procedures to separate water from ethanol. The prohibitively high cost of azeotropic distillation has lead to exploration of alternate separation methods based on selective adsorption of water versus ethanol. ' Various materials have been evaluated as adsorbents, including calcium chloride, barium oxide, metallic sodium, silica gel, starch, cellulose, protein, and other biopolymers2z3 The carbohydrate-based materials starch and cellulose exhibited the greatest retention for water and could potentially be used for ethanol dehydration. Further studies of starch-based materials indicated that adsorption of water was enhanced as the amount of amylopectin increa~ed.~ However, no thermodynamic information relating the preferential adsorption of water versus ethanol has been presented for the tested materials.Complex carbohydrates constitute a major part of agricultural crop residues and food waste, which may be a potentially useful source of materials for alcohol dehydration. In addition, other compounds, like simpler carbohydrates and proteins, should also be considered for their effect on separating water from ethanol.The objectives in this study were: 1) To examine the retention behavior of water and ethanol in sucrose, lactose, sweet whey solids, calcium sulfate, potato starch, and cellulose by using inverse gas chromatography.2) To calculate the free energies and enthalpies of adsorption for water and ethanol on each selected material, so that a better understanding of the involved mechanisms of equillibria could be obtained. MATERIALS AND METHODSPacking materials used were anhydrous calcium sulfate (W. A. Hammond Drierite Company), sucrose (J. T. Baker Chemical Co.), sweet whey, a-cellulose, and a-lactose (Sigma Chemical Co.). Packing materials were first meshed to obtain the SO/lOO sized fraction. Fractions were then dried in an air oven at 104" for 3 h and allowed to cool in a dessicator for 1 h. Whey was dried in a vacuum oven at 60°C under a 30 in. Hg vacuum and dessicated for 1 h * To whom correspondence should be addressed to prevent denaturation of proteins. Each of the materials were diluted with Anakrom Q SO/lOO mesh, which is a treated diatomaceous earth, inert to water and ethanol. Net retention times of water and ethanol for each packing material were corrected to account for the weight of the packing material and Anakrom Q using the procedure established previously.4Packing material densities were measured experimentally using a densimeter. Values obtained were 1.60 g/mL for sucrose, 2.60 g/mL calcium sulfate, 1.76 g/mL potato starch, 1.25 g/mL cellulose, 1.48 g/mL lactose, and 1.12 g/mL sweet whey.Inverse gas chromatography (IGC) has been used to study the adsorption behavior of water and ethanol on each packing material.' Details of the apparatus -used have been given elsewhere4 and need not to be repeated here. Using retention time data a separation factor can be defined as:where t N w and tNE are the net retention times o...
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