Thermodynamics of α-angelicalactone polymerization

Figures & data

Figure 1. Structures of the possible α-angelicalactone polymers.

Figure 2. Temperature dependence of the PAL heat capacity.  (M_r∼1300. ABC, crystalline; AIE, partly crystalline; AB, vitreous; DEN, high elastic; EMH, apparent melting heat capacity; ENK, liquid; EL, metastable liquid).

Table 1. Experimental thermodynamic parameters of the glassy state and devitrification of the PAL, and reference data on poly-γ-butyrolactone (PBL) (8) and poly-δ-valerolactone (PVL) (8)

	$\mathrm{\Delta }{T}_{\text{g}}^{\circ }$^a (K)	$T_{\text{g}}^{\circ }$^b (K)	$H_{\text{g}}^{\circ }$(0) – $H_{\text{cr}}^{\circ }$ (0)^c (kJ/mol)	$\mathrm{\Delta }{C}_{\text{p}}^{\circ }$ ($T_{\text{g}}^{\circ }$)^d (J/(mol K))	$S_{\text{conf}}^{\circ }$^e (J/(mol K))	S^0(0)^f (J/(mol K))
PAL	210–225	214 ± 1	2.5	21.8 ± 5	3.6 ± 1	4.0 ± 1
PBL	–	214	7.9	58	–	19
PVL	–	207	11.7	65	–	30

^a Glass transition temperature range.

^b Glass transition temperature.

^c Difference between the enthalpies of the crystalline and amorphous states at 0 K.

^d Heat capacity change at the glass transition temperature.

^e Conformational entropy.

^f Entropy at 0 K.

Table 2. Experimental melting parameters of the PAL, and reference data on poly-γ-butyrolactone (PBL) (8) and poly-δ-valerolactone (PVL) (8)

	$\mathrm{\Delta }{T}_{\text{m}}^{\circ }$^a (K)	$T_{\text{m}}^{\circ }$^b (K)	$\mathrm{\Delta }{H}_{\text{m}}^{\circ }$^c (kJ/mol)	$\mathrm{\Delta }{S}_{\text{m}}^{\circ }$^d (J/(mole K))	$\mathrm{\Delta }{C}_{\text{p}}^{\circ }$ ($T_{\text{m}}^{\circ }$)^e (J/(mole K))
PAL^f	350–380	368 ± 1	6.5 ± 0.1	17.7 ± 0.3	16.7 ± 0.5
PBL^g	–	338 ± 1	13.2 ± 0.3	39.4 ± 0.6	29
PVL^h	–	331 ± 2	18.2 ± 0.3	55 ± 1	40

^a Melting temperature range.

^b Melting point.

^c Melting enthalpy.

^d Entropy of melting.

^e Heat capacity change at the melting point.

^f Crystallinity 67%.

^g Crystallinity 100%.

^h Crystallinity 100%.

Figure 3. Temperature dependency of melted/crystalline ratio β during the PAL melting.

Scheme 1. Synthesis of α-angelicalactone (3). Reaction conditions: (a) HCl (cat.), 370–373 K, 4 h; (b) H₃PO₄ (cat.), 25 Torr, 340–345 K.

Table 3. Standard enthalpies of combustion ($-\mathrm{\Delta }{H}_{\text{c}}^{\circ }$) and formation ($-\mathrm{\Delta }{H}_{\text{f}}^{\circ }$) of αAL and the PAL (T = 298.15 K, p^o = 0.1 MPa)

Substance (physical state)	$-\mathrm{\Delta }{H}_{\text{c}}^{\circ }$ (kJ/mol)	$-\mathrm{\Delta }{H}_{\text{f}}^{\circ }$ (kJ/mol)
PAL (high-elastic)	2,545.31 ± 0.16	279.73 ± 0.61
αAL (liquid)	2,578.72 ± 0.12	246.32 ± 0.65

Table 4 Thermodynamic parameters of lactones polymerization (p = 101.325 kPa)

Lactone → polylactone	T (K)	Physical state^a (L/PolyL)	$-\mathrm{\Delta }{H}_{\text{pol}}^{\circ }$ (kJ/mol)	$-\mathrm{\Delta }{S}_{\text{pol}}^{\circ }$ (J/(mole K))	$-\mathrm{\Delta }{G}_{\text{pol}}^{\circ }$ (kJ/mol)
αAL → PAL	100	cr/cr	19.37	23.00	17.07
αAL → PAL	220	cr/cr	29.93	32.54	22.77
αAL → PAL	298.15	l/he	33.41	42.69	20.68
αAL → PAL	400	l/l	50.44	104.13	8.78
γBL → PBL^b	298.15	l/he	−5	30	−14
βPL → PPL^b	298.15	l/he	75	54	59
δVL → PVL^b	298.15	l/he	10.5	15	6

^a cr—crystalline, gl—glassy, l—liquid, he—high-elastic.

^b Lebedev (8).

Table 5. Strain energies (in kJ/mol) for δVL, γVL, αAL and γBL

Source	δVL	γVL	αAL	γBL
Our calculation	–	30.6	38.9	33.0
Chen et al. (14)	41.4	30.8	39.5	32.6
Brown et al. (35)	39.7	30.5	–	32.2

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