Objective

To determine the solubility of the nineteen liquid carboxylic acids and two aldehydes listed below in methanol
Formic acid
Glacial Acetic acid
Propionic acid
Butyric acid
Valeric acid
Hexanoic acid
Octanoic acid
Cyclohexanecarboxylic acid
Isovaleric acid
Cyclohexanepropionic acid
2-Ethylhexoic acid
3-Mercaptopropionic acid
Methacrylic acid
Linoleic acid
Trichloroacetic acid
Methoxy acetic acd
2-Octenoic acid
(+)-2-phenyl butyric acid
2-Methyl butyric acid
2-Ethyl butyraldehyde
trans-2-hexen-1-al





Procedure

A solution of liquid acids and aldehydes in methanol was prepared by adding 2mL of the acid /aldehyde drop-wise in 600uL methanol in one dram vial. Misciblity of the compound was visually confirmed and pictures were obtained.

Results

Fully miscible solutions of aldehydes in methanol.
Acid Solutions 1-7
Acid Solutions 8-14
Acid Solutions 15-19
Aldehyde Solutions 20, 21
Spreadsheet
Methanol: Hexanes solutions

Discussion

Since all the liquid acids and aldehydes used in this experiment, were found to to be fully miscible in methanol (Separation of layers was not seen during the addition of the compounds to methanol). Concentration of their saturated saturated solutions therefore can be calculated using there densities.
Miscibility experiment performed for binary solutions of methanol / hexanes shows that there is a miscibility gap only for certain compositions, others form homogeneous solutions. Solutions with methanol mole fractions ranging 0.38-0.71 formed two phases and solutions with methanol mole fractions from 0.76-0.94 from homogenous solutions. This is consistent with Max and Chapados 2008 paper.
Based on the observations from this experiment and also from the literature it seems reasonable to assume that binary solutions may have a miscibility gap for certain compositions only.

Conclusion

The concentrations of liquid aldehydes, and there saturated solutions in methanol are tabulated below.

Compopund

Conc (M)

Formic acid (99%)
26.5
Acetic acid
17.5
Propionic acid
13.4
Butyric acid
10.9
Valeric acid
9.2
Hexanoic acid
7.98
Octanoic acid
6.31
Cyclohexanecarboxylic acid
8.05
Isovaleric acid
9.05
Cyclohexanepropionic acid
5.84
2-Ethylhexanoic acid
6.26
3-Mercaptopropionic acid
11.5
Methacrylic acid
11.8
Linoleic acid
3.21
Trichloroacetic acid
9.91
Methoxy acetic acid
13.0
2-Octenoic acid
6.63
(+)-2-phenyl butyric acid
6.42
2-Methyl butyric acid
9.16
2-Ethyl butyraldehyde
8.12
trans-2-hexen-1-al
8.62


Log

2008-12-22

13:00 Obtained 19 liquid carboxylic acids and two liquid aldehydes
13:30 Labeled and arranged 21 one dram vials in a sequence
14:00 To each vial methanol (600uL) was added by a micropipettor. Compounds corresponding to vial numbers are listed in the table below
1)Formic acid
2)Glacial Acetic acid
3)Propionic acid
4)Butyric acid
5)Valeric acid
6)Hexanoic acid
7)Octanoic acid
8) Cyclohexanecarboxylic acid
9)Isovaleric acid
10)Cyclohexanepropionic acid
11)2-Ethylhexanoic acid
12)3-Mercaptopropionic acid
13)Methacrylic acid
14)Linoleic acid
15)Trichloroacetic acid
16)Methoxy acetic acd
17)2-Octenoic acid
18)(+)-2-phenyl butyric acid
19)2-Methyl butyric acid
20)2-Ethyl butyraldehyde
21)trans-2-hexen-1-al




14:35 Using a micropipettor 2mL of each pure sample was added to corresponding vial drop-wise.
15:00 No separation of layers was observed at any point during the addition of pure samples to the vials. In cases of viscous liquids a gently swirl of the solution made it completely miscible in methanol.
16:30 Completed the adding the samples to methanol
16:40 Pictures were obtained after every seven additions of the pure samples to methanol..Timestamps are provided at the bottom of the pics.

2008-12-30

18:00 Made-up 9 solutions of methanol / hexanes to check their miscibility. Solutions of the following compositions were made
mL:mL
1:1
0.8:1
0.6:1
0.4:1
0.2:1
1:0.8
1:0.6
1:0.4
1:0.2