The Vaporization Enthalpy and Vapor Pressure of - American

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The Vaporization Enthalpy and Vapor Pressure of (d)‑Amphetamine and of Several Primary Amines Used as Standards at T/K = 298 As Evaluated by Correlation Gas Chromatography and Transpiration Melissa Thornton and James Chickos* Department of Chemistry and Biochemistry, University of Missouri-St. Louis, St. Louis, Missouri 63121, United States

Inna V. Garist,+ Mikhail A. Varfolomeev,§ Aleksei A. Svetlov,⊥ and Sergey P. Verevkin Department of Physical Chemistry, University of Rostock, Dr-Lorenz-Weg-1, D-18059 Rostock, Germany S Supporting Information *

ABSTRACT: The vapor pressures of several aliphatic and phenyl substituted primary amines at T/K = 298.15 are measured by transpiration studies, and their vaporization enthalpies are calculated. The results were combined with compatible literature values to evaluate both the vaporization enthalpy and vapor pressure of (d)-amphetamine by correlation gas chromatography. The results are compared to existing values either estimated or measured for racemic amphetamine. Vaporization enthalpies and vapor pressures at T/K = 298.15 of the following were measured by transpiration (kJ·mol−1, p/Pa): 1-heptanamine, (49.75 ± 0.38, 291); 1-octanamine, (55.05 ± 0.29, 108); 1-decanamine, (64.94 ± 0.32, 12); benzylamine, (54.32 ± 0.32, 88); (dl)-α-methylbenzylamine, (55.26 ± 0.33, 82); 2-phenethylamine (57.51 ± 0.35, 43). The use of several of these materials as standards resulted in a vaporization enthalpy and vapor pressure for (d)-amphetamine at T/K = 298.15 of (58.2 ± 2.7) kJ mol−1 and (38 ± 12) Pa. S-(+)-Amphetamine ((d)-α-methylphenethylamine) or (d)-2amino-1-phenylpropane is a drug that has been used recreationally, as a performance enhancer, an antidepressant, and as a decongestant (Benzedrine, Smith Kline, and French).1 It is highly regulated but generally available by prescription in the United States in Adderall,2 a treatment for attention deficit hyperactivity disorder (ADHD) in the form of an amine salt. Despite the use and widespread misuse of this drug, relatively little experimental thermochemical information is available in the literature. An experimental measure of the vapor pressure of (d)-amphetamine at T/K = 293 has been reported as (32 ± 3) Pa.3 At T/K = 298.15 a vapor pressure of 40 Pa is estimated by ACD Laboratories software as cited by SciFinder Scholar.4 The EPI Suite5 estimates a similar vapor pressure value. Estimates of the vaporization enthalpy of (43.77 ± 3.0)kJ·mol−1 are also reported for amphetamine.4 Although a reference temperature is not provided by the ACD Lab, the pressure of p/Pa = 101 326 that is cited implies that this value is the vaporization enthalpy at the boiling temperature. Assuming this to be correct, then adjustment to T/K = 298.15 using the protocol described below results in a vaporization enthalpy of (58.2 ± 5.9) kJ mol−1 for (d)-amphetamine. An experimental vaporization enthalpy for (dl)-amphetamine of 53.4 kJ mol−1 has been reported at the mean temperature, T/K = 343.6 The original reference to this work is not available. Adjusted to T/K = 298.15 also described below results in a value of (57.1 ± 1.1) kJ mol−1. In view of the lack of experimental data and the limited amounts of (d)-amphetamine commercially available, © XXXX American Chemical Society

both the vaporization enthalpy and vapor pressures of this material were evaluated by correlation gas chromatography. The selection of standards for use by correlation gas chromatography can significantly affect the quality of the results obtained. Structurally similar standards with comparable retention times are preferable. Data for suitable materials currently available included benzylamine, (dl)-α-methylbenzylamine, 2-phenethylamine, and 1-decanamine. Table 1 lists the vaporization and vapor pressure data available in the literature for these materials. The structure of these and some additional primary amines studied are provided in Figure 1. Vapor pressures at T/K = 298.15 were calculated from the available pressure−temperature equations. Since the original data are available in several different mathematical formats, all have been converted to the same format for comparison purposes. Several concerns arose upon examination of the data in this table. While the vapor pressures for the first two entries for benzylamine appear in very good agreement,7,8 the vaporization enthalpies for these entries lie outside the uncertainties reported. A third value is quite old and the last entry is considerably different.9,10 Additionally, the constants reported in the first entry for (dl)-α-methylbenzylamine do not reproduce the vapor pressures reported;7 the vaporization Received: March 3, 2013 Accepted: May 23, 2013

A

dx.doi.org/10.1021/je400212t | J. Chem. Eng. Data XXXX, XXX, XXX−XXX

Journal of Chemical & Engineering Data

Article

Table 1. Equation Parameters,a Vaporization Enthalpies, and Vapor Pressures of Some Primary Amines from the Literature ΔlgHm(Tm)

T compound benzylamine

(dl)-α-methyl-benzylamine 2-phenethylamine (dl)-amphetamine (d)-amphetamine 1-decanamine

A

B

313 363 458

25.5 ± 0.2 25.8 ± 0.1 19.557

6257 ± 69 6340 ± 38 5889

52.1 ± 0.6 (298) 52.7 ± 0.3 (328) 49.0 ± 2.1 (380)

318 318 352 353

22.3 ± 0.1 22.08 26.3 ± 0.1 25.63

6584 ± 34 4414.8 6704 ± 30 6428

54.7 ± 0.3 (303) 36.7 55.7 ± 0.2 (313) 53.4 (343)

6747 ± 71 6110

43.8 ± 3.0 (475)e 56.1 ± 0.6 (380) 50.8g (458)

K range 283 to 293 to 302 to 298.15 283 to 292 to 273 to 333 to

−1

329 to 431 443 to 473

20.55 17.01

kJ·mol

(K)

ΔlgHm(298 K)

p

kJ·mol−1

Pa,b 298.15 K

ref

91 95 110 na 1.2c 1440 45 59 32 ± 3d

7 8 9, 10 11, 12 7 6 8 6 3 4 13 6

52.0 54.6 54.4 60.2 55.0 37.3

± 0.6 ± 0.3 ± 1.3 ± 0.3

11f 13h

Clausius−Clapeyron equation: ln(p/Pa) = A − B/(T/K). bEvaluated and/or extrapolated to T/K = 298.15. cVapor pressure cited at T/K = 298.4; a vapor pressure of p/Pa = 1.2 is calculated from the equation given. dVapor pressure at T/K = 293. eVaporization enthalpy estimate from ref 4; boiling temperature experimental from ref 14. fExperimental vapor pressures were fit to the following third order polynomial and extrapolated to T/ K = 298.15 K: ln(p/Pa) = AT −3 + BT−2 + CT + D. The vapor pressures at T/K = 298.15 were calculated from this polynomial. Constants for the polynomial are provided in the Supporting Information. gThe vaporization enthalpy was calculated using vapor pressures calculated over the temperature range noted and fit to the Clausius−Clapeyron equation. hThe vapor pressures were calculated from the Antoine equation, log (p/kPa) = A′ − B′/(C′ + T), derived from measurements over the temperature range, T/K = (410 to 506); [A′, 6.4229; B′, 1844.7; C′, −76.05], ref 6. a

■

EXPERIMENTAL SECTION Materials. The origin of the standards and their purities are listed in Table 2. The liquid samples of alkaneamines used in Rostock were obtained from Aldrich and Fluka and further purified by repetitive distillation in vacuum. The degree of purity was determined by GC. No impurities (greater than mass fraction 5 × 10−4) could be detected in samples for thermochemical study. The products were analyzed on a Hewlett-Packard gas chromatograph 5890 series II with a flame ionization detector and Hewlett-Packard 3390A integrator. Additional details are provided in the Supporting Information. The materials used in St. Louis with the exception of benzylamine were from the same supplier and of similar purity; all were used as purchased. Benzylamine contained approximately 7 minor components, all less than a mass fraction of 0.01. Sample purity is not an important issue with the correlation gas chromatography technique since the chromatography generally separates the impurities. The analysis of the certified (d)-amphetamine (as the hemisulfate) as provided by the supplier was approximately 0.735. Only one volatile peak other than the solvents was observed in the free base when analyzed by gas chromatography. S-(d)-Amphetamine (as the hemisulfate) reference standard was purchased in a methanolic solution from Restek (cat no.

Figure 1. The structures of the amines investigated (top to bottom, left to right): 1-heptanamine, 1-octanamine, 1-decanamine, (dl) αmethylbenzylamine, 2-phenethylamine, and S-(d)-amphetamine.

enthalpy of the second entry seems unreasonably small.6 The first vaporization enthalpy listed for 1-decanamine is also quite old,13 and the second requires a large temperature adjustment (17.5 ± 2.6 kJ mol−1) from the mean temperature of measurement to T/K = 298.15.6 Similarly, its vapor pressure at T/K = 298.15 required a temperature extrapolation of the Antoine equation of well over 100 K. In view of these concerns, measurements for all these materials were repeated, including those for 2-phenethylamine. Additional vaporization enthalpies and vapor pressures for 1-heptanamine and 1-octanamine are also reported to determine how well the linear 1-alkanamines correlate in correlation gas chromatography experiments for the reason described below. Table 2. Origin of the Standards and Targets and Their Analysis

mass fraction compound

CASRNs

supplier

benzylamine (dl)-α-methylbenzylamine 1-heptanamine 2-phenethylamine 1-octanamine (d)-amphetamine 1-decanamine

100-46-9 618-36-0 111-68-2 64-04-0 111-86-4 51-64-9 2016-57-1

Aldrich MCBa Aldrich Aldrich Fluka Aldrich Restek Aldrich

Rostock 0.99 0.99 0.99 0.99 0.995 reference standardc 0.95

GC St. Louis

Rostock

0.96 0.99 0.99 ASb 0.995

> > > > >

0.995 0.995 0.995 0.995 0.995

0.95

> 0.99

Matheson, Coleman, and Bell. bAnalytical standard. cAvailable as the hemisulfate in methanolic solution at 1000 μg/mL; purity level 0.735 as described in the certificate; no other peaks were observed in the GC trace of the free base.

a

B



Article

Table 3. Vapor Pressures p and Enthalpies of Vaporization, ΔlgHm, Obtained by the Transpiration Method (R = 8.313 J·mol−1·K−1) T/Ka

m/mgb

(pexp − pcalc)/Pa

ΔlgHm/kJ·mol−1

1.47 78.23 1.36 94.51 1.47 108.83 1.47 123.19 1.47 140.76 1.47 164.13 1.47 190.74 1.47 221.91 1.47 248.84 1.52 288.48 1.52 328.82 1.52 379.97 1.52 409.78 1.52 502.65 1-octanamine;ΔlgHm (298.15 K) = (55.05 ± 0.29) kJ·mol−1 316.77 82836.99 93.2 ⎛ T /K ⎞ ⎟ ln(p/Pa) = − − ln⎜ ⎝ 298.15 ⎠ (6) R (RT /K) R

−0.22 2.84 2.00 −0.99 −3.20 −2.35 −1.31 0.91 −4.88 −4.09 −5.50 1.27 5.73 13.43

51.27 51.10 50.94 50.77 50.60 50.43 50.26 50.09 49.92 49.74 49.57 49.41 49.32 49.07

3.00 15.7 3.00 20.8 3.00 27.4 3.00 32.5 1.24 34.7 3.00 42.8 1.24 42.8 3.00 51.7 1.24 54.5 3.00 67.7 1.24 69.0 3.00 84.0 1.24 85.6 1.24 83.4 1.24 104.7 1.16 106.4 1.16 135.3 1.16 129.4 1.24 136.9 1.24 134.1 1.16 131.2 1.16 132.8 1.16 165.3 1.24 166.7 1.24 211.3 1.16 210.2 1.24 249.4 1.16 257.8 1.16 305.1 1.24 312.1 1.16 323.8 1-decanamine; ΔlgHm(298.15 K) = (64.94 ± 0.32) kJ·mol−1 348.00 97651.03 109.7 ⎛ T /K ⎞ ⎟ ln(p/Pa) = − − ln⎜ ⎝ 298.15 ⎠ (7) R R (R /K)

0.9 0.4 0.2 −0.3 0.8 1.7 −0.4 −2.1 −1.1 −1.6 −0.3 −2.0 −1.1 −3.3 −2.4 −3.9 1.8 −5.1 2.4 −0.5 −4.3 −2.7 0.8 1.0 6.8 2.8 −3.5 3.2 14.0 7.1 12.8

57.12 56.82 56.54 56.35 56.32 56.12 56.07 55.84 55.81 55.57 55.57 55.33 55.33 55.33 55.09 55.05 54.83 54.83 54.83 54.83 54.82 54.82 54.59 54.58 54.32 54.31 54.06 54.05 53.88 53.82 53.80

0.3 0.0 0.4 0.2

64.85 64.72 64.60 64.31

V(N2)/dm3c

flow of N2/dm3·h−1

p/Pad −1

K) = (49.75 ± 0.38) kJ·mol 298.91 75059.34 84.9 ⎛ T /K ⎞ ⎟ ln(p/Pa) = − − ln⎜ ⎝ 298.15 ⎠ (5) R (RT /K) R 1-heptanamine;

280.2 282.2 284.2 286.2 288.2 290.2 292.2 294.2 296.2 298.3 300.3 302.2 303.2 306.2

2.16 1.83 2.18 2.06 2.05 2.03 1.93 2.00 1.97 2.03 4.04 2.45 2.40 2.95

0.614 0.429 0.442 0.368 0.319 0.270 0.221 0.197 0.172 0.152 0.267 0.140 0.127 0.127

274.2 277.7 281.0 283.2 283.6 285.9 286.5 289.2 289.6 292.4 292.4 295.2 295.3 295.3 298.1 298.5 301.1 301.2 301.2 301.2 301.3 301.3 304.0 304.1 307.1 307.3 310.2 310.3 312.3 313.0 313.3

1.21 1.13 1.21 1.36 2.72 2.81 2.46 2.72 2.23 2.69 2.82 3.34 1.89 1.84 2.20 2.62 2.50 2.53 3.02 3.41 2.97 3.41 2.38 4.60 3.50 3.03 3.72 4.78 4.40 5.17 4.67

1.500 1.050 0.850 0.800 1.469 1.250 1.076 1.000 0.765 0.750 0.765 0.750 0.414 0.414 0.393 0.464 0.348 0.368 0.414 0.476 0.426 0.484 0.271 0.517 0.310 0.271 0.279 0.348 0.271 0.310 0.271

299.1 300.2 301.3 304.0

2.52 2.33 2.63 2.41

3.000 2.564 2.564 1.909

ΔlgHm(298.15

3.27 3.27 3.27 3.27

13.0 14.0 15.8 19.5

C



Article

Table 3. continued T/Ka

m/mgb

V(N2)/dm3c

306.2 307.3 308.6 310.2 312.2 313.2 315.1 316.2 317.2 320.0 320.9 323.2 324.3 324.3 327.2 330.1 330.1 332.8 332.8 333.1 333.1 335.9 335.9 338.9 338.9 341.9 341.9 343.0

2.38 2.78 2.58 2.28 2.96 2.33 1.09 2.27 2.27 2.15 1.28 2.33 2.15 2.16 1.88 3.29 3.30 3.34 2.91 2.97 2.99 3.86 3.87 4.91 4.86 5.60 5.53 6.75

1.603 1.637 1.364 1.091 1.266 0.841 0.364 0.682 0.631 0.504 0.273 0.445 0.364 0.364 0.273 0.375 0.375 0.309 0.273 0.281 0.281 0.300 0.281 0.300 0.284 0.281 0.281 0.309


p/Pad

5.06 22.8 3.27 26.2 1.09 29.1 3.27 32.1 5.06 36.0 2.52 42.6 1.09 46.0 1.78 51.2 2.52 55.3 1.78 65.5 1.09 72.2 1.78 80.5 1.09 91.1 1.09 91.4 1.09 106.0 1.13 135.0 1.09 135.6 1.09 166.1 1.09 164.5 1.13 162.8 1.09 163.5 1.13 197.9 1.09 211.9 1.13 251.9 1.09 262.8 1.13 306.4 1.09 302.5 1.13 335.7 benzylamine; ΔlgHm (298.15 K) = (54.26 ± 0.32) kJ·mol−1 283.56 73456.05 64.40 ⎛ T /K ⎞ ⎟ ln(p/Pa) = − − ln⎜ ⎝ 298.15 ⎠ (8) R R(T /K) R

Series 1 from 2006 (unpublished results) 275.5 1.16 1.937 278.6 1.25 1.624 281.5 1.46 1.494 284.5 1.74 1.299 287.6 1.89 1.137 290.5 2.10 1.043 293.5 2.21 0.841 296.5 2.41 0.706 298.4 1.77 0.470 301.3 2.35 0.478 303.4 9.39 1.696 303.4 3.62 0.660 304.3 3.01 0.510 307.4 3.51 0.478 308.3 9.83 1.272 308.4 3.80 0.495 310.3 4.32 0.478 313.4 5.36 0.495

1.94 14.37 1.95 18.28 1.95 23.07 1.95 31.35 1.95 38.74 2.02 46.95 2.02 60.98 2.02 78.84 1.88 86.90 1.91 113.71 5.09 127.69 1.98 126.34 1.91 136.29 1.91 169.27 5.09 178.08 1.98 176.71 1.91 208.16 1.98 249.07 benzylamine; ΔlgHm (298.15 K) = (54.39 ± 0.32) kJ·mol−1 283.93 73594.45 64.40 ⎛ T /K ⎞ ⎟ ln(p/Pa) = − − ln⎜ ⎝ 298.15 ⎠ (9) R R(T /K) R

Series 2 from 2013 276.7 2.66 276.7 2.76 279.6 2.67 279.6 2.81 282.3 2.72 282.3 2.81

4.320 4.320 3.312 3.312 2.520 2.520

4.32 4.32 4.32 4.32 4.32 4.32

14.72 15.25 19.12 20.04 25.34 26.15 D

(pexp − pcalc)/Pa

ΔlgHm/kJ·mol−1

−0.3 0.8 1.0 0.1 −1.5 2.0 −0.9 0.2 0.3 −2.2 −0.2 −4.9 −1.4 −1.0 −7.3 −3.2 −2.6 0.4 −1.2 −6.2 −5.5 −5.2 8.8 5.8 16.6 9.4 5.5 17.8

64.07 63.95 63.80 63.63 63.41 63.30 63.09 62.97 62.86 62.55 62.45 62.20 62.08 62.08 61.76 61.44 61.44 61.15 61.15 61.12 61.12 60.81 60.81 60.48 60.48 60.15 60.15 60.03

0.30 −0.16 −0.52 1.08 −0.16 −1.96 −0.65 1.59 −1.99 4.03 0.36 −0.99 0.65 1.20 −0.60 −3.19 3.72 −1.82

55.72 55.52 55.33 55.14 54.94 54.75 54.56 54.36 54.24 54.06 53.92 53.92 53.86 53.66 53.60 53.60 53.48 53.28

−0.67 −0.14 −0.75 0.16 0.31 1.12

55.78 55.78 55.59 55.59 55.41 55.41



Article

Table 3. continued V(N2)/dm3c


(pexp − pcalc)/Pa

m/mgb

285.7 285.7 288.0 288.0 291.6 291.6 294.2 294.2 297.7 297.7 300.3 300.3 303.3 303.5 306.1 306.3 309.4 309.5 312.2 312.3 312.3 315.6

2.70 2.61 2.37 2.37 2.26 2.26 2.09 2.09 2.05 2.05 1.89 1.89 2.40 2.00 2.33 1.81 2.38 2.34 2.91 3.63 3.74 3.62

1.823 4.21 34.58 1.823 4.21 33.41 1.403 4.21 39.34 1.403 4.21 39.34 0.976 1.72 53.62 0.976 1.72 53.62 0.747 1.72 64.87 0.747 1.72 64.87 0.574 1.72 82.47 0.574 1.72 82.47 0.431 1.72 101.48 0.431 1.72 101.48 0.431 1.72 128.31 0.365 1.46 126.00 0.365 1.46 146.86 0.276 1.10 151.35 0.294 1.17 187.10 0.276 1.10 195.07 0.294 1.17 228.39 0.368 1.10 227.18 0.368 1.10 233.88 0.276 1.10 301.64 α-methyl-benzylamine; ΔlgHm (298.15 K) = (55.26 ± 0.33) kJ·mol−1 294.23 76812.64 72.3 ⎛ T /K ⎞ ⎟ ln(p/Pa) = − − ln⎜ ⎝ 298.15 ⎠ (10) R R(T /K) R

1.62 0.44 −0.38 −0.38 0.94 0.94 0.46 0.46 −1.30 −1.30 −0.05 −0.05 2.85 −1.07 −6.27 −2.95 −3.82 2.73 −1.90 −5.41 1.30 14.22

55.20 55.20 55.05 55.05 54.82 54.82 54.65 54.65 54.42 54.42 54.25 54.25 54.06 54.05 53.88 53.87 53.67 53.66 53.49 53.48 53.48 53.27

283.6 287.8 291.3 291.3 295.3 299.2 303.1 307.1 311.0 314.9 318.9 322.8

2.66 3.23 4.59 5.99 3.54 4.94 5.47 5.25 4.14 4.43 4.85 5.82

2.220 2.22 25.09 1.885 1.88 35.34 1.920 1.92 49.28 2.486 2.49 49.51 1.100 1.10 65.95 1.143 1.14 88.66 0.948 0.95 118.31 0.694 0.69 155.16 0.419 0.42 202.43 0.348 0.35 260.21 0.293 0.29 339.07 0.272 0.27 439.07 2-phenethylamine; ΔlgHm (298.15 K) = (57.51 ± 0.35) kJ·mol−1 299.28 79837.30 74.9 ⎛ T /K ⎞ ⎟ ln(p/Pa) = − − ln⎜ ⎝ 298.15 ⎠ (11) R R(T /K) R

−0.67 −0.95 1.23 1.47 0.27 0.69 0.76 −0.07 −0.44 −4.18 −2.33 1.84

56.31 56.01 55.76 55.76 55.46 55.18 54.90 54.61 54.33 54.04 53.76 53.47

285.2 287.4 288.2 288.2 290.1 293.1 293.2 298.2 298.2 298.3 300.1 302.0 303.2 303.3 303.3 304.2 305.1 305.1 306.4 308.2

1.66 1.66 1.37 1.42 1.52 2.13 0.89 2.80 1.93 1.84 3.02 3.06 1.86 2.60 1.98 2.66 3.66 3.66 3.10 2.62

2.226 1.860 1.427 1.518 1.339 1.518 0.583 1.242 0.911 0.849 1.183 1.037 0.582 0.836 0.637 0.778 1.037 0.985 0.776 0.585

0.23 −0.21 0.22 −0.25 0.10 −0.61 1.55 2.26 −0.88 −0.27 0.75 0.90 0.57 −1.10 −1.96 −0.21 −2.79 0.94 −0.25 −0.84

58.48 58.31 58.25 58.25 58.11 57.89 57.88 57.51 57.51 57.50 57.36 57.22 57.13 57.12 57.12 57.06 56.99 56.99 56.89 56.76

3.04 4.46 3.06 3.04 4.46 3.04 1.35 1.36 3.04 2.55 3.09 3.11 3.04 1.36 2.55 3.11 3.11 3.11 1.37 1.35

p/Pad

ΔlgHm/kJ·mol−1

T/Ka

15.45 18.17 19.89 19.42 23.16 28.88 31.29 46.48 43.34 44.30 51.96 60.07 65.32 64.14 63.28 69.55 71.77 75.50 81.76 92.58 E



Article

Table 3. continued T/Ka

m/mgb

V(N2)/dm3c


p/Pad

(pexp − pcalc)/Pa

ΔlgHm/kJ·mol−1

308.2 310.4 311.2 313.2 313.4 314.2 317.2 318.2 318.4 320.2 323.2

3.90 3.13 3.18 4.59 2.85 3.08 2.16 7.06 3.06 2.60 2.93

0.911 0.601 0.543 0.708 0.449 0.459 0.242 0.759 0.337 0.242 0.225

3.04 1.39 1.02 3.04 1.35 1.02 1.04 3.04 1.35 1.04 1.04

87.80 106.74 120.07 133.12 131.06 137.40 181.78 189.10 187.78 218.66 265.45

−5.62 −2.54 4.45 0.21 −3.70 −4.99 7.25 2.51 −1.31 5.72 6.82

56.76 56.59 56.53 56.38 56.37 56.31 56.08 56.01 55.99 55.86 55.63

a Saturation temperature; uncertainty ± 0.1 K. bMass of transferred sample condensed at T/K = 243. cVolume of nitrogen used to transfer mass m of sample. dVapor pressure at temperature T. Calculated from m and the residual vapor pressure at the cooling temperature T/K = 243; uncertainty in pressure within 3 % of the reported value.

Table 4. Compilation of Some Thermodynamic Properties of Some Primary Aminesa ΔlgHm(Tm) (Tm/K)

T compounds benzylamine

M

b

T DM

K range

−1

−1

J·mol ·K

kJ·mol (K)

300 363 458

52.0 ± 0.6 (298) 52.7 ± 0.3 (328) 48.96 (380)

313 316

54.5 54.4

T T

283 to 293 to 302 to 298.15 276 to 277 to

C BP T

298.15 327 to 430 280 to 306

43.4 ± 0.6 (379) 50.2 ± 0.4 (293)

T T

283 to 318 284 to 323 292 to 318

54.7 ± 0.3 (301) 54.9 36.8 (305)

DM T

273 to 352 285 to 323

55.7 ± 0.2(313)

BP EB T

308 to 453 344 to 494 274 to 313

47.8 ± 0.4 (381) 43.5 ± 0.4 (419) 55.3 ± 0.3 (294)

na est GC

333 to 353

53.4 43.8 ± 3.0 (475)

−ΔlgCp (Cpl) −1

66.6 (215.6)

value (avg) 1-heptanamine

α-methyl-benzylamine

2-phenethyl-amine

1-octanamine

(dl)-amphetamine (d)-amphetamine 1-decanamine

BP T

443 to 473 329 to 431 299 to 343

84.9 (285.7) 84.9 (285.7) value (avg) 73.2(241) 73.2(241) value 74.9(247.5) value (avg) 93.2 (317.6) 93.2 (317.6) value (avg) 81.5 (272.9) 81.5 (272.9)

50.8 (458) 56.1 ± 0.6 (380) 64.9 (321)

109.7 (381.4) 109.7 (381.4) 109.7 (381.4) value (avg)

ΔlgHm(298.15 K)

p

kJ·mol−1

Pa, 298.15 K

ref

52.1 ± 0.6 54.6 ± 0.3 54.4 ± 1.3 60.2 54.3 ± 0.3 54.4 ± 0.3 54.4 ± 0.2 50.0 ± 0.1 50.2 ± 1.4 49.8 ± 0.4 50.0 ± 0.2 55.0 ± 0.3 55.3 ± 0.3 36.7 55.2 ± 0.4 56.8 ± 0.2 57.5 ± 0.3 57.2 ± 0.3 55.5 ± 2.3 54.6 ± 0.5 55.1 ± 0.3 55.1 ± 0.5 57.1 ± 1.1 58.2 ± 5.9

91 95 110 na 88 87 90

7 8 9, 10 11, 12 this work this work

68.3 ± 2.6 65.1 ± 0.6 64.9 ± 0.3 65.0 ± 0.2

287c 291 289 1.2d 82 1440 82 44 43 44 136c 122c 108 108 59 32.3e 13c 11f 12 12

23 13 this work 7 this work 6 8 this work 13 24 this work 6 4 6 6 13 this work

a

Values in bold are the values used in calculating the mean. Uncertainties in the mean represent 1 standard deviation of the values in bold. bMethod used for measurement: DM, MKS differential manometer; T, transpiration; C, calorimetry; BP, point as a function of pressure; EB, ebulliometer; na, not available; est, estimated; GC, adsorption−desorption gas chromatography. cExtrapolated to T/K = 298.15 K from temperature range noted. d Calculated from the equation provided; vapor pressure reported: in p/Pa = 123.4 (T/K = 298.4). eVapor pressure at T/K = 293. fCalculated from the vapor pressures provided over the range noted; see Supporting Information for the polynomial used for the calculation.

34020) in 1 mg quantities. Evaporation of the methanol followed by addition of a drop of 1 M NaOH generated the free base which was extracted with hexane and analyzed by gas chromatography. A small KOH pellet was then added to the organic solution to remove any moisture. The hexane solution was then transferred to a second vial and allowed to evaporate. A dilute methanolic solution containing all the standards was

then added dropwise to a highly concentrated hexane solution of the free base and analyzed until comparable concentrations of (d)-amphetamine and standards were achieved. Methanolic solutions of (d)-amphetamine and standards appeared to give better peak shapes for the chromatograms run at the lower temperatures. Experiments performed on the 1-aminoalkanes F



Article

Table 5. A Summary of the Correlations of Three Primary 1-Alkanamines ΔHtrn(434 K) run 1

slope T/K

intercept

1-heptanamine 1-octanamine 1-decanamine

−4280.0 −4677.8 −5316.9

10.553 10.974 11.458

kJ·mol

−1

ΔlgHm(298 K) (lit)

ΔlgHm(298 K) (calc)

−1

kJ·mol−1

kJ·mol

50.0 ± 0.2 55.1 ± 0.5 65.0 ± 0.2

35.58 38.89 44.20

49.7 ± 4.6 55.5 ± 4.8 64.8 ± 5.1

Δ1g Hm(298.15 K)/kJ·mol−1 = (1.75 ± 0.09)ΔHtrn(434 K) − (12.6) ± 5.5) r 2 = 0.9976

(12) ΔHtrn(429 K)

ΔlgHm(298 K) (lit)

ΔlgHm(298 K) (calc)

run 2

slope T/K

intercept

kJ·mol−1

kJ·mol−1

kJ·mol−1

1-heptanamine 1-octanamine 1-decanamine

−4526.6 −4827.3 −5302.3

11.114 11.315 11.426

37.63 40.13 44.08

50.0 ± 0.2 55.1 ± 0.5 65.0 ± 0.2

49.7 ± 7.0 55.6 ± 7.2 64.8 ± 7.5

Δ1g Hm(298.15 K)/kJ·mol‐1 = (2.34 ± 0.13)ΔHtrn(429 K) − (38.4 ± 5.1) r 2 = 0.9971

(13)

were run in pentane. In both cases, the solvent also served as the nonretained reference.

■

Δ1g Hm(298.15K)/( kJ·mol−1) = Δ1g Hm(Tm) + [(10.58 + 0.26*Cp(1)/( J ·mol−1 K−1)

METHODS

(Tm/K − 298.15)]/1000

Rostock − Transpiration Measurements. Vapor pressures of alkaneamines were determined using the method of transpiration. Details of this method have been published elsewhere.15,16 Additional details of these experiments are provided in the Supporting Information. St. Louis: Correlation Gas Chromatography. Measurements of vaporization enthalpy and vapor pressure by correlation gas chromatography have also been reported recently.17,18 Details pertaining to these experiments are also available in the Supporting Information as are the retention times of all analytes. Adjusted retention times, ta, for each analyte in the mixture were calculated from each respective retention time and the retention time of the solvent, which was not retained by the column, by difference. The adjusted retention time, a measure of the time an analyte spends on the column, has been shown to be inversely proportional to its vapor pressure off the column. A plot of ln(to/ta) vs 1/T where to is the reference time, 60 s, results in a linear relationship in which the slope of the line measures the enthalpy of transfer of the analyte from the column to the gas phase divided by the gas constant, −ΔHtrn/R. This enthalpy is related to the vaporization enthalpy (ΔlgHm(T)) by eq 1, where ΔHintr(Tm) is the interaction enthalpy of the analyte with the column.19 Provided suitable standards are chosen, ΔlgH(T) (where T can represent another temperature including T/K = 298.15), is found to correlate linearly with ΔHtrn(Tm). The equation describing the correlation can then be applied to evaluate the vaporization enthalpy of the target, in this case (d)-amphetamine. ΔHtrn(Tm) = Δ1g Hm(Tm) + ΔHintr(Tm)

(2) 6

Temperature adjustments for 1-decanamine, (dl)-amphetamine,6 and the estimated values for (d)-amphetamine4 discussed above are provided in Table 4. Uncertainties. All uncertainties associated with temperature adjustments using eq 2 were calculated as follows: an uncertainty of 16·(Tm/K − 298.15 K)/1000 kJ·mol−1 was associated with the second term of eq 2. The uncertainties associated with combined properties were calculated as (u12 + u22 + ...)0.5 where u represents the uncertainty in each term. Uncertainties in the vaporization enthalpies and vapor pressures evaluated by correlation in the following tables were calculated from the uncertainties in both the slope and intercept.

■

RESULTS AND DISCUSSION Vapor Pressures and Vaporization Enthalpies. Vapor pressures of alkaneamines measured in this work are reported in Table 3 and the results were treated with eqs 3 and 4, respectively R ln pi sat = a + b/T + Δl g Cp ln[T /To]

(3)

Δl g Hm(T ) = −b + Δl g CpT

(4)

where pisat is vapor pressure; a and b are adjustable parameters; To is an arbitrarily chosen reference temperature (To is 298.15 K in this work); and ΔlgCp is the difference of the molar heat capacities of the gaseous and the liquid phase calculated using the second term of eq 2. Values of ΔlgCp (see Tables 3 and 4) were calculated from the isobaric molar heat capacities Cp(l) of alkanamines using the group contribution method of Acree and Chickos.20,21 Experimental results and parameters a and b are listed in Table 3. Vapor pressures derived from the transpiration method have been reliable within 3% and their accuracy was governed by reproducibility of the GC analysis.15 The temperature dependence of vapor pressure for the amines studied is provided as eqs 5 to 11 in Table 3. To assess the uncertainty of the vaporization enthalpy, the experimental data were approximated with the linear equation ln(pisat) = f(T−1)

(1)

Temperature Adjustments. The temperature adjustments of vaporization enthalpy to T/K = 298.15 discussed above were achieved using eq 2.20 The term Cp(l) in this equations refers to the heat capacity of the liquid at T/K = 298.15 which has been estimated using a group additivity approach.21 G



Article

surface. After careful drying in an oven at t/°C = 110, they were used for loading with the sample into the saturator. Deactivation of the glass beads appears to be a prerequisite for reproducible measurements on amines. The disagreement of our results for benzylamine and (dl)-α-methylbenzylamine in a previous work7 is apparently due at least in part to this reason. Correlation Experiments with n-Alkanamines. As an additional validation of the values measured for the 1alkanamines, experiments were also performed to determine how well the vaporization enthalpies correlated with the corresponding enthalpies of transfer as measured by correlation chromatography. Previous work has demonstrated that homologous series correlate exceptionally well in these experiments (i.e., ref 17 and references cited). The results for the 1-alkanamines evaluated in these experiments are reported in Table 5 (runs 1 and 2) and illustrated by the circles in Figure 2 for run 1. The uncertainties in the figure represent two standard deviations of the mean value of the standards reported in Table 4. Equations 12 and 13 listed below each correlation in Table 5 describe the correlation observed. The vaporization enthalpy values obtained by correlation are nearly within the small uncertainty associated with the mean values reported in Table 4. The linearity of the results seem entirely consistent with expectations and corroborate the values measured by transpiration. These results are summarized for runs 1 and 2 in the last two columns of Table 7. The rather large uncertainties associated with eqs 12 and 13 are likely due to the few compounds included in these correlations. Vaporization Enthalpy of (d)-Amphetamine. Table 6 (runs 3 and 4) summarizes the vaporization enthalpy results for results for (d)-amphetamine obtained by correlation using both aromatic and aliphatic primary amines other than aniline and its derivatives. Work not previously described suggested that primary aliphatic amines do not correlative as well with aromatic amines such as aniline and its derivatives. Two independent sets of correlations are described by eqs 15 and 16 and are listed below each respective correlation. Complete details are provided in the Supporting Information and the results from Table 6 are also summarized in Table 7. The

Figure 2. Plots of vaporization enthalpies at T/K = 298 against the enthalpies of transfer at Tm/K = 434 for run 1 for the C7, C8, and C10 n-alkanamines (•) and for benzyl-, α-methylbenzyl-, phenethyl- and 1decanamine (■) for run 3 at T/K = 414 by correlation gas chromatography. The error bars for both runs represent two standard deviations of the mean value used for the standards.

using the method of least-squares. The uncertainty in the enthalpy of vaporization was assumed to be identical with deviation of experimental ln(pisat) values from this linear correlation. Table 4 summarizes the vaporization enthalpies from this work and those from the literature. The values in bold are those used in calculating the average value used in the correlation gas chromatography experiments. The transpiration measurements on amines in this work have been performed as usual in accordance with the well-established procedure previously described15,16 However, previous work has established that amines are very reactive on the glass beads used in the experiments and that some sort of stabilization of the amines was required.22 Consequently, the glass beads used in transpiration experiments have been washed with 0.1 N NaOH in order to suppress any possible acidity of the glass Table 6. Results of the Correlations for (d)-Amphetamine

ΔHtrn(414 K)

ΔlgHm(298 K) (lit)

ΔlgHm(298 K) (calc) kJ·mol−1

run 3

slope T/K

intercept

kJ·mol−1

kJ·mol−1

benzylamine (dl)-α-methylbenzylamine 2-phenethylamine (d)-amphetamine 1-decanamine

−4271.6 −4415.2 −4680.1 −4766.3 −5579

10.209 10.388 10.733 10.796 12.216

35.51 36.71 38.91 39.63 46.38

54.4 ± 0.2 55.2 ± 0.4 57.1 ± 0.3 65.0 ± 0.2

54.1 55.3 57.5 58.2 64.9

± ± ± ± ±

1.9 1.9 2.0 2.0 2.2

Δ1g Hm(298.15 K)/kJ·mol−1 = (0.99 ± 0.04)ΔHtrn(414 K) + (18.9 ± 1.4) r 2 = 0.9974

(14) ΔHtrn(424 K)

run 4

slope T/K

intercept

benzylamine (dl) α-methylbenzylamine 2-phenethylamine (d)-amphetamine 1-decanamine

−4280.89 −4420.53 −4728.26 −4761.47 −5565.67

10.2 10.4 10.8 10.8 12.2

g

−1

Δ1 Hm(298.15 K)/kJ·mol

Δl Hm(298 K) (lit) g

−1

−1

kJ·mol

kJ·mol

54.4 ± 0.2 55.2 ± 0.4 57.2 ± 0.3

35.59 36.75 39.31 39.58 46.27

65.0 ± 0.2

ΔlgHm(298 K) (calc) kJ·mol−1 54.0 55.2 57.8 58.1 64.8

± ± ± ± ±

3.3 3.3 3.4 3.4 3.7

= (1.01 ± 0.6)ΔHtrn(424 K) − (18.1 ± 2.4)

r 2 = 0.9927

(15) H



Article

Table 7. A Summary of the Vaporization Enthalpies in kJ·mol−1 of Both Standards and Target at T/K = 298.15 run 1 benzylamine 1-heptanamine (dl) α-methylbenzylamine 2-phenethylamine 1-octanamine (d)-amphetamine 1-decanamine a

run 2

49.7 ± 4.6

run 3

run 4

54.1 ± 1.9

54.0 ± 3.3

average

55.3 ± 1.9 57.5 ± 2.0

55.2 ± 3.3 57.8 ± 3.4

58.2 ± 2.0 64.9 ± 2.2

58.1 ± 3.4 64.8 ± 3.7

49.7 ± 7.0

55.5 ± 4.8

55.6 ± 7.2

64.8 ± 5.1

64.8 ± 7.5

54.1 49.7 55.3 57.7 55.6 58.2 64.8

± ± ± ± ± ± ±

2.6 5.8 2.6 2.6 6.0 2.7 4.6

lit 54.4 50.0 55.2 57.1 54.7 57.1 65.0

± ± ± ± ± ± ±

0.2 0.2 0.4 0.6 0.3 1.1a 0.2

Vaporization enthalpy for (dl)-amphetamine.

Table 8. Correlation of ln (to/ta)avg with ln (p/po) at T/K = 298.15 for Runs 1 and 2 (po = 101 325 Pa) ln (to/ta)avg runs 1 and 2 1-heptanamine 1-octanamine 1-decanamine

−3.926 −4.792 −6.366

ln (p/po) exp −5.86 −6.844 −9.041 runs 1 and 2:

ln(p /po ) = (1.32 ± 0.07) ln((to/ta) − (0.64 ± 0.34)

ln (p/po) calc

p/Pa calc

p/Pa exp

−6.957 −7.881 −9.035

307 ± 166 98 ± 59 12 ± 9

289 108 12

r 2 = 0.9974

(16)

Vapor pressures: 1-Alkanamines. The vapor pressure of the 1-alkanamines were calculated by correlating ln (p/po) against ln (to/ta)avg. The p/Pa term refers to the vapor pressures of the standards at T/K = 298.15 from Table 4, po/Pa = 101 325 and ln (to/ta)avg represents the average value calculated from the slope and intercept of both target and standards correlated in runs 1 and 2 of Table 5. The ln(to/ta)avg, term was evaluated by first calculating to/ta for both runs at T/K = 298.15, averaging the resulting values and then converting the average to the natural logarithm. The result of the correlation is summarized in Table 8 and illustrated by the triangles in Figure 3. The calculated values agree quite well with those from Table 4. The uncertainty in the value by correlation gas chromatography was estimated from the uncertainty in both the slope and intercept of eq 16. As noted above, the fairly large uncertainty associated with the vapor pressures calculated likely reflects the few data points included in the correlation. Vapor Pressures: (d)-Amphetamine at T/K = 298.15. The vapor pressures of the standards and of (d)-amphetamine were evaluated similarly using the results from runs 3 and 4 of Table 6 The results are summarized in Table 9 and the correlation of the standards is illustrated by the solid circles in Figure 3. The solid square in the figure represents the results obtained for (d)-amphetamine. The values calculated for the standards are listed in the last two columns of Table 9 and are in very good agreement with the experimental values from Table 4. A vapor pressure of p/Pa = (38 ± 12) at T/K = 298.15 is calculated for (d)-amphetamine, which compares with the following previous values: p/Pa = 32 measured at T/K = 293 by

Figure 3. A plot of ln (p/po) of the standards against the corresponding values of ln(to/ta) measured for the standards at T/K = 298.15. The triangles represent the results obtained for the nalkanamines of runs 1 and 2. The solid circles (•) represent the results from runs 3 and 4. The solid square (■) represents the corresponding value obtained for (d)-amphetamine at T/K = 298.15. The equations of the lines calculated by a linear regression are given by eq 16 and 17.

vaporization enthalpy of (58.2 ± 2.7) kJ·mol−1 evaluated in this work for (d)-amphetamine is within experimental error with both the value of (57.1 ± 1.1) obtained by extrapolation of the vaporization enthalpy of (dl)-amphetamine6 and the estimated value of (58.2 ± 5.9) kJ·mol−1 also obtained by extrapolation from the boiling temperature.4

Table 9. Correlation of ln(to/ta)avg with ln(p/po) at T/K = 298.15 K for Runs 3 and 4 (po = 101 325 Pa) benzylamine (dl)-α-methylbenzylamine 2-phenethylamine (d)-amphetamine 1-decanamine

ln (to/ta)avg runs 3 and 4

ln (p/po) exp

ln (p/po) calc

−4.138 −4.424 −5.010 −5.180 −6.482

−7.026 −7.124 −7.742

−6.957 −7.211 −7.731 −7.881 −9.035

−9.041 runs 3 and 4:

ln(p /po ) = (0.89 ± 0.04) ln((to/ta) − (3.29 ± 0.22) a

r 2 = 0.9952

p/Pa calc

p/Pa exp

± ± ± ± ±

90 82 44 32a, 40b 12

96 75 44 38 12

28 22 14 12 4

(17)

Vapor pressure for (d)-amphetamine at T/K = 293.3 bEstimated.5 I



Article

adsorption-thermal desorption gas chromatography,3 or p/Pa = 40 estimated by ACD software.4 This can be compared to a value of p/Pa = 59 obtained by extrapolation as described above for racemic amphetamine also at T/K = 298.15.6 The uncertainty in the vapor pressure of (d)-amphetamine was evaluated as described above for the 1-alkanamines using the uncertainties in eq 17.

2,6-Dimethylpiperidine in the Range between 0.2 and 75 Pa. J. Chem. Eng. Data 2009, 54, 819−822. (9) Carson, A.; Laye, P.; Yrekli, M. The Enthalpy of Formation of Benzylamine. J. Chem. Thermodyn. 1977, 9, 827−9. (10) Stull, D. R. Vapor Pressure of Pure Substances, Organic Compounds. Ind. Eng. Chem. 1947, 39, 517−540. (11) Majer, V.; Svoboda, V. Enthalpies of Vaporization of Organic Compounds; IUPAC Chemical Series No 32; Blackwell Scientific: Oxford UK, 1985. (12) Kusano, K.; Saito, Y. Proc. Joint Meeting Kyushu, Chugoku and Shikoku Branches. Chem. Soc. Jpn 1976, 60. (13) Ralston, A. W.; Selby, W. M.; Pool, W. O.; Potts, R. H. Boiling Points of n-Alkyl Primary Amines. Ind. Eng. Chem. 1940, 32, 1093− 1094. (14) Budavari, S., Ed. The Merck IndexAn Encyclopedia of Chemicals, Drugs, and Biologicals; Merck and Co., Inc.: Whitehouse Station, NJ, 1996; p 98. (15) Kulikov, D.; Verevkin, S. P.; Heintz, A. Enthalpies of vaporization of a series of aliphatic alcohols. Experimental results and values predicted by the ERAS-model. Fluid Phase Equilib. 2001, 192, 187−207. (16) Verevkin, S. P. Pure Component Phase Changes Liquid and Gas. In Experimental Thermodynamics: Measurement of the Thermodynamic Properties of Multiple Phases; Weir, R. D., De Loos, Th. W., Eds.; Elsevier: New York, 2005; Vol 7, pp 6−30. (17) Wilson, J. A.; Chickos, J. S. Vaporization Enthalpy and Vapor Pressure of Valproic Acid by Correlation Gas Chromatography. J. Chem. Eng. Data 2012, 57, 2281−2285. (18) Gutterman, A.; Rath, N.; Chickos, J. Validation of the Vaporization Enthalpies of Some Simple Aliphatic Amides and Their Use in Evaluation the Vaporization Enthalpy of Valpromide and Valnoctamide. J. Chem. Eng. Data 2013, 58, 749−757. (19) Peacock, L. A.; Fuchs, R. Enthalpy of Vaporization Measurements by Gas Chromatography. J. Am. Chem. Soc. 1977, 99, 5524−5. (20) Acree, W., Jr.; Chickos, J. S. Phase Transition Enthalpy Measurements of Organic and Organometallic Compounds. Sublimation, Vaporization and Fusion Enthalpies From 1880 to 2009. J. Phys. Chem. Ref. Data 2010, 39, 1−942. (21) Chickos, J. S.; Hesse, D. G.; Liebman, J. F. A Group Additivity Approach for the Estimation of Heat Capacities of Organic Liquids and Solids. Struct. Chem. 1993, 4, 261−268. (22) Pozdeev, V. A.; Verevkin, S. P. Vapour Pressure and Enthalpy of Vaporization of Linear Aliphatic Alkanediamines. J. Chem. Thermodyn. 2011, 43, 1791−1799. (23) Wadso, I. Enthalpies of Vaporization of Organic Compounds. III. Amines. Acta Chem. Scand. 1969, 23, 2061−2064. (24) Steele, W. V.; Chirico, R. D.; Knipmeyer, S. E.; Nguyen, A.; Smith, N. K.; Tasker, I. R. Thermodynamic Properties and Ideal-Gas Enthalpies of Formation for Cyclohexene, Phthalan (2,5-Dihydrobenzo-3,4-furan), Isoxazole, Octylamine, Dioctylamine, Trioctylamine, Phenyl Isocyanate, and 1,4,5,6-Tetrahydropyrimidine. J. Chem. Eng. Data 1996, 41, 1269−1284.

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SUMMARY The vapor pressure and vaporization enthalpies of a series of some aliphatic and aromatic primary amines were measured by transpiration and the results compared to existing values in the literature. Vaporization enthalpy results on the aliphatic amines were also evaluated by correlation gas chromatography. Mean values for these materials were then used to evaluate similar properties for (d)-amphetamine. Due to restrictions on the commercial availability of (d)-amphetamine, these experiments illustrate a unique application of correlation gas chromatography to provide two thermochemical properties on amounts not easily measurable by other methods.

■

ASSOCIATED CONTENT

S Supporting Information *

Details of the transpiration, and correlation gas chromatography studies, and tables of retention times. This material is available free of charge via the Internet at http://pubs.acs.org.

■

AUTHOR INFORMATION

Corresponding Author

*E-mail: [email protected]. Notes

The authors declare no competing financial interest. + On leave from Mogilev State University of Food Technologies, Mogilev, Belarus. § On leave from Department of Physical Chemistry,Chemical Institute, Kazan (Volga region) Federal University, Kazan, Russia. ⊥ On leave from Chemical Department, Samara State Technical University, Molodogvardeyskaya 244, Samara 443100, Russia.

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REFERENCES

(1) Rasmussen, N. Making the First Anti-Depressant: Amphetamine in American Medicine, 1929−1950. J. Hist. Med. Allied. Sci. 2006, 61, 288−323. (2) Drugs.com. http://www.drugs.com/monograph/adderall.html (accessed 12/1/12). (3) Lawrence, A. H.; Elias, L.; Authier-Martin, M. Determination of Amphetamine, Cocaine, And Heroin Vapour Pressures Using a Dynamic Gas Bleeding System and Gas Chromatographic Analysis. Can. J. Chem. 1984, 62, 1886−8. (4) SciFinder Scholar, software V11.02; Advanced Chemistry Development (ACD/Laboratories): Toronto, Ontario, 1994−2012. (5) Calculated using the EPI Suite. http://www.epa.gov/oppt/ exposure/pubs/episuitedl.htm (accessed 12/1/12). (6) Calculated from The Antoine Constants reported at the temperature indicated. Stephenson, R. M.; Malanowski, S. Handbook of the Thermodynamics of Organic Compounds; Elsevier: N. Y., 1987. (7) Verevkin, S. P. Strain Effects in Phenyl-Substituted Methanes. Geminal Interaction between Phenyl and the Electron-Releasing Substituents in Benzylamines and Benzyl Alcohols. J. Chem. Eng. Data 1999, 44, 1245−1251. (8) Mokbel, I.; Razzouk, A.; Sawaya, T.; Jose, J. Experimental vapor Pressures of 2-Phenylethylamine, Benzylamine, Triethylamine, and cisJ


The Vaporization Enthalpy and Vapor Pressure of - American

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