Properties of Aliphatic and Aromatic Aldehydes under High Pressure Compressibility and Viscosity Determination P. MITRA CHAUDHURI', R. A. STAGER, and G. P. MATHUR Department of Chemical Engineering, University of Windsor, Windsor, Ontario, Canada Compressibility and viscosity measurements have been made on seven aliphatic and three aromatic aldehydes a t pressures up to 20,000 p.s.i.g. The viscosity data have been correlated by means of a n empirical equation. Experimental data are presented in graphical form for the pressure range investigated.
D A T A on t h e viscosity and compressibility of liquids are generally scarce. Previous investigations have concentrated mainly on organic compounds. T h e work on high pressure physical properties was pioneered by Bridgman (1). Almost no work has so far been reported on aldehydes, possibly because they are difficult t o work with. T h e aliphatic aldehydes are low boiling liquids with a disagreeable smell and are harmful t o t h e h u m a n system. T h e aromatic aldehydes have a tendency t o be oxidized t o their corresponding acids.
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EXPERIMENTAL
Concurrent measurements of t h e physical properties were conducted in a compact apparatus ( 3 ) . Compressibility was measured by a piston displacement device ( 2 ) in conjunction with viscosity measurement, which was performed by a 6). falling cylinder method (4, Pressure was generated in t h e equipment by means of a manually operated hydraulic pump. T h e pressure was measured by a Bourdon gage. T h e precision of pressure ~h.e temperature was measurement was within ~ 0 . 2 ' T measured by calibrated thermometers t o a n accuracy of '2'
'Present address: General Electric Co., Guelph. Ontario. Canada
VOL. 13, N o . 1 , JANUARY 1968
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eACET4LDEHYDE P'OPIONALDEHYDE t BUTYRALDEHYDE +ISOBUTY RADEHYDE AISOVALERALDEHYDE *HE P T A L D E H YDE
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METHOD OF OPERATION
Before starting experiments with t h e aldehydes, several test runs were made with various liquids of known viscosity t o examine t h e accuracy of t h e apparatus. Plummets of different dimensions were tried t o find t h e optimum plummet size. T h e authors discovered t h a t plummets with
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T h e compressibility meter consisted of a 16-inch long, I ,-inch I.D. stainless steel t u b e with cap-collar-gland assembly a t b o t h ends. Inside t h e t u b e there was a pistonmagnet assembly soldered together. Outside t h e compressibility meter was a magnet-pointer assembly. T h e pointer indicated t h e position of t h e piston t o one t e n t h of a millimeter. T h e viscometer consisted of a fall t u b e , 152.5294 cm. long with 0.4710 cm. inside diameter. T h e t u b e was of stainless steel. T h e plummet used was a thin hollow cylinder of a uniform outside diameter of 0.43688 cm. with hemispherical ends. Bridgman h a d used plummets with three projecting lugs t o keep t h e plummet coaxial during its fall. T h e lugs introduced some error in t h e measurements a n d were omitted in t h e present setup. Modified electrical contacts, with specially designed plugs, m a d e t h e use of lugs unnecessary. T h e coaxial fall of t h e plummet through t h e viscometer t u b e was confirmed by means of a stethoscope.
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PRESSURE X
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Figure 2. Viscosity-pressure diagrams
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Table I. Viscosity and Compressibility Data
Press.. P.S.I.G. 2.000 4,000 6.000 8,000 10.000 12.000 14,000 16.000 18,000 20.000 2,000 4,000 6.000 8,000 10.000 12,000 14.000 16,000 18,000
Relative Viscosity. v ' 71.
Compressibility. Volume Change. -1v.cc.
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A V 'k'
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Acetaldehyde. 71.6' F.. 0, = 0.3468 cp. 1.08335 0.6774 1.86 1.1462 1.2725 3.49 1.20030 1.7789 4.87 1.2598 2.2252 6.10 1.3091 2.6145 7.16 1.3620 2.9880 8.19 1.4098 3.3267 9.11 1.4568 3.6306 9.99 1.5068 3.9186 10.74 l..5478 4.1877 11.47 Propionaldehyde. 74.3' F.. q , = 0.4293 cp. 1.0&%
0.5064 1.0919 0.9812 1.1390 1.3896 1.1944 1.7726 1.2593 2.1113 1.:3
