College of Veterinary Medicine The University of Tennessee, Knoxville, USA.
Reclamation of large volumes of acetone by freeze-vacuum distillation was practical, simple. economical to perform, and environmentally wise. The apparatus, constructed primarily from items found within a plastination laboratory, proved to be effective for the distillation of the various percentages (45 - 94%) of acetone used for conducting this study. Three liter aliquots, of known acetone content, were distilled over a six hour period and resulted in reclamation of 94 to 98 percent acetone. Further distillation , of the remaining lower percentage acetone (2 - 20%), provided residual solutions to as low as 1 percent acetone. Freeze-vacuum distillation has served to reduce operating costs both by reclamation of large volumes of quality acetone and significantly reducing the volume of hazardous waste which must be disposed.
acetone; distillation; recycling
Janick, L.M. College of Veterinary Medicine The University of Tennessee, Knoxville, USA.
An integral part of the plastination process is dehydration of specimens, a process which exchanges tissuefluid (water ) and excess fats with an organic solvent. Cold acetone (-25°C) is usually the best solvent for dehydration (von Hagens, 1986; Henry, 1992). This process, however, leads to an accumulation of waste acetone (contaminated by water and fats) which necessitates not only the purchase of new acetone, but the disposal of the old acetone as a hazardous waste. Although previous work has characterized methods for effectively distilling acetone (Roark, 1992; Grodin and Berube, 1992), the practicality of freeze-vacuum distillation for both large volume applications and significant reduction of hazardous waste has not been addressed.
(1) Nalgene 114 L. (30 gal.) tank (60x60x30cm.) Nalge mfg. # 141000021
(1) Large Pyrex dessicator D. flange 250mm with a 55/38 sleeve Corning mfg. #3120250
(2) 5 meter Rolls of 6mm D. copper tubing ( 1) Needle valve (Hll4, Biodur)
( 1) Nalgene polyethylene vacuum tubing
( 1) vacuum gauge reading inches of Hg
(2) Bi-vented 2 liter cylinders fabricated from 18 gauge stainless steel
( 1) vacuum pump
( 10) medium size rocks
( 1) Sub zero freezer
Prior to distillation, fat was removed from waste acetone by freeze separation (Grondin and Berube, 1992). A three liter aliquot of the waste acetone (45 to 94 percent) was placed into a dessicator along with 10 medium size rocks. The rocks served as a bumping agent to catalyze the vaporization of the acetone. The desiccator and acetone were warmed in a 40°C water bath (Nalgene tank). Vacuum was applied, increased until the acetone boiled ( 19 to 25 inches of mercury) , and then stabilized by adjusting the needle valve. As vacuum increased, the liquid acetone vaporized and flowed, via polyethylene tubing, to a copper condensing coil in -15°C freezer. The combination of warming the liquid waste acetone and applying vacuum facilitated the vaporization of the acetone in the desiccator. With the subsequent chilling of the vapor in the condensation coil, much of the acetone returned to the liquid state and collected in the first canister. Any remaining acetone vapor passed through the second copper condensing coil and most of any remaining acetone was collected in the second canister. The system concluded with the vacuum line coursing from the second canister, out of the freezer, to an elevated vacuum pump. A needle valve, for vacuum regulation, was placed in this line. Each 3L aliquot of waste acetone was distilled for a six hour period. Reclaimed acetone was collected at 2 hour intervals. Subsequent to each collection, the vacuum was reapplied to a level sufficient to promote further boiling.
Reclaimed acetone (over 6 hour periods) was collected with purities reaching 98 percent from the higher distillates to 94 percent from the lower distillates (Table 1). Maximum volume loss for this operation was maintained at or below 4 percent indicating a fairly efficient system. Residual waste products ranged from 20 to 2 percent in a corresponding fashion. Further distillation of small quantities of low percentage acetone was not efficient. However, distillation of cumulative solutions (3 liters of 2 to 20% acetone) did prove effective for reducing the percentage of acetone to near 1percent. Depending on local restrictions, this concentration ( 1%) of acetone may be easily disposed. Even if disposal as a hazardous waste is required, the overall quantities become considerably reduced (Table 1). Therefore, this procedure reduces the cost of waste disposal and reclaims large volumes of acetone for re-use in the dehydration process.
| % Acetone |
Total Volume Collected |
Total Volume Remaining |
Total Volume |
Volume lost |
| 94% | 2580 ml
98% Acetone |
300 ml
20% Acetone |
120 ml |
4% |
| 87% | 2425 ml
97% Acetone |
460 ml
14% Acetone |
115 ml |
4% |
| 70% | 2000 ml
97% Acetone |
900 ml
10% Acetone |
lOO ml |
3% |
| 58% | 1370 ml
95% Acetone |
1370 ml
5% Acetone |
80 ml |
3% |
| 45% | 1220 ml
94% Acetone |
1760 ml
2% Acetone |
20 ml |
1% |
ACKNOWLEDGMENTS
We gratefully appreciate the assistance of the university of Tennessee College of Veterinary Medicine Art Department: Debbie Haines and Kim Cline.
Grondin, G:, S Berube: A simple and inexpensive method for recycling used acetone in plastination laboratories. J. Int. Soc. Plastination 6:17-19, 1992.
https://doi.org/10.56507/VRMT8219
Henry, RW: Plastination - Dehydration of specimens. Presented at The 2nd Interim Conference on Plastination, Chaffey College, Rancho Cucamonga, California, USA August 1991 J. Int. Soc. Plastination 6:4, 1992.
Roark, R: High purity solvent recycling of acetone in the plastination laboratory. Presented at The 2nd Interim Conference on Plastination, Chaffey College, Rancho Cucamonga, California, USA August 1991J. Int. Soc. Plastination 6: 6, 1992.
von Hagens, G: Heidelberg Plastination Folder; Collection of all technical leaflets for plastination. Anatomisches Institut 1, Universitat Heidelberg, 1986
