Thermodynamics of depolymerization of biotechnological poly[(R)‐3‐hydroxybutyrate] with formation of (R,R,R)‐4,8,12‐trimethyl‐1,5,9‐trioxadodeca‐2,6,10‐trione and of its polymerization with ring‐opening to highly isotactic poly[(R)‐3‐hydroxybutyrate] from 0 to 500 K at standard pressure

Быкова, Т. А.; Kiparisova, E. G.; Vasilyev, V.G.

doi:10.1002/macp.1996.021970431

Cited by 4 publications

(2 citation statements)

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“…Thermodynamic Data. The thermodynamic data of TBL, PHB, and PHB‘ were determined by Lebedev et al at the Lobachevski State University Nizhny Novgorod (Russian Federation) . The isobaric heat capacity, melting temperatures, and melting enthalpies were determined in the temperature range from 5 to 340 K using a vacuum adiabatic calorimeter TAU-1.…”

Section: Experimental Partmentioning

confidence: 99%

“…In the present paper we report experimental results on the depolymerization of poly[( R )-3-hydroxybutyrate] (PHB) and on the polymerization of the cyclic trilactone ( R , R , R )-4,8,12-trimethyl-1,5,9-trioxacyclododeca-2,6,10-trione (TBL) yielding a low molecular weight poly[( R )-3-hydroxybutyrate] (PHB‘). The experimental results are discussed in the light of the thermodynamic parameters of PHB depolymerization and TBL polymerization obtained from calorimetric measurements performed by Lebedev et al…”

Section: Introductionmentioning

confidence: 99%

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Depolymerization of Poly[(R)-3-hydroxybutyrate] to Cyclic Oligomers and Polymerization of the Cyclic Trimer: An Example of Thermodynamic Recycling

Melchiors¹,

Keul²,

Höcker³

1996

Macromolecules

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Biotechnologically produced poly[(R)-3-hydroxybutyrate] (PHB) was subjected to catalytic depolymerization in the melt and in solution. In the melt depolymerization yields crotonic acid beside linear oligomers according to an ester pyrolysis reaction independent of the catalyst used. In solution cyclic oligomers were obtained via back-biting reactions. Efficient catalysts for this reaction are dibutyltin dimethoxide and p-toluenesulfonic acid. The thermodynamic parameters of the depolymerization of PHB to yield (R,R,R)-4,8,12-trimethyl-1,5,9-trioxacyclododeca-2,6,10-trione (TBL) were determined from calorimetric measurements by Lebedev et al. as a function of temperature at standard pressure (p = 101.325 kPa) and are at T = 400 K: ΔH°depol = −43 kJ·mol-1, ΔS°depol = 66 J·K-1 mol-1, and ΔG°depol = −70 kJ·mol-1. The experimental results are in full agreement with these values. Polymerization of TBL in the melt with dibutyltin dimethoxide as initiator results in poly[(R)-3-hydroxybutyrate] (PHB‘) of low molecular weight (M n = 5 × 103), the spectroscopic characteristics are identical with those of the biotechnologically produced material. The thermodynamic parameters of the polymerization were determined from calorimetric measurements by Lebedev et al. as a function of temperature; they are at standard pressure (p = 101.325 kPa) and a polymerization temperature of T = 400 K: ΔH°pol = 12 kJ·mol-1, ΔS°pol = −32 J·K-1·mol-1, and ΔG°pol = 25 kJ·mol-1. These results contradict the polymerization experiment. The factors which may contribute to a decrease of ΔG°pol are discussed.

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Section: Experimental Partmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Depolymerization of Poly[(R)-3-hydroxybutyrate] to Cyclic Oligomers and Polymerization of the Cyclic Trimer: An Example of Thermodynamic Recycling

Melchiors¹,

Keul²,

Höcker³

1996

Macromolecules

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Energy storage efficiency in artificial photosynthesis – An evaluation method in engineering perspective

Sun

Jia

Shi

et al. 2023

Energy Conversion and Management

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Phase Transition Enthalpy Measurements of Organic and Organometallic Compounds and Ionic Liquids. Sublimation, Vaporization, and Fusion Enthalpies from 1880 to 2015. Part 2. C11–C192

Acree

Chickos

2017

Journal of Physical and Chemical Reference Data

126

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The second part of this compendium concludes with a collection of phase change enthalpies of organic molecules inclusive of C11–C192 reported over the period 1880–2015. Also included are phase change enthalpies including fusion, vaporization, and sublimation enthalpies for organometallic, ionic liquids, and a few inorganic compounds. Paper I of this compendium, published separately, includes organic compounds from C1 to C10 and describes a group additivity method for evaluating solid, liquid, and gas phase heat capacities as well as temperature adjustments of phase changes. Paper II of this compendium also includes an updated version of a group additivity method for evaluating total phase change entropies which together with the fusion temperature can be useful in estimating total phase change enthalpies. Other uses include application in identifying potential substances that either form liquid or plastic crystals or exhibit additional phase changes such as undetected solid–solid transitions or behave anisotropically in the liquid state.

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Cited by 4 publications

References 7 publications

Depolymerization of Poly[(R)-3-hydroxybutyrate] to Cyclic Oligomers and Polymerization of the Cyclic Trimer: An Example of Thermodynamic Recycling

Depolymerization of Poly[(R)-3-hydroxybutyrate] to Cyclic Oligomers and Polymerization of the Cyclic Trimer: An Example of Thermodynamic Recycling

Energy storage efficiency in artificial photosynthesis – An evaluation method in engineering perspective

Phase Transition Enthalpy Measurements of Organic and Organometallic Compounds and Ionic Liquids. Sublimation, Vaporization, and Fusion Enthalpies from 1880 to 2015. Part 2. C11–C192

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