A Study on the Optically Active Polymer Poly‐β‐pinene

Cataldo, Franco; Gobbino, Marco; Ursini, Ornella; Angelini, Giancarlo

doi:10.1080/10601320701561197

Cited by 22 publications

(9 citation statements)

References 13 publications

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“…It is well known that high‐energy radiation always works against the preservation of the enantiomeric excess (Cataldo 2007b; Cataldo, Ursini & Angelini 2008) through the well‐known phenomenon of radioracemization. Only in exceptional cases can the radiolysis of certain substrates surprisingly lead to an enhancement of the optical activity rather than to radioracemization, which implies a reduction of the optical activity (Cataldo et al 2007, 2009).…”

Section: Resultsmentioning

confidence: 99%

Amino acids in comets and meteorites: stability under gamma radiation and preservation of the enantiomeric excess

Iglesias‐Groth¹,

Cataldo²,

Ursini³

et al. 2010

Monthly Notices of the Royal Astronomical Society

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Amino acids in Solar system bodies may have played a key role in the chemistry that led to the origin of life on Earth. We present laboratory studies testing the stability of amino acids against high energy radiation. All the 20 chiral amino acids in the levo form found in the proteins of the current terrestrial biochemistry were irradiated in the solid state with γ -radiation to a dose of 3.2 MGy, which is the dose equivalent to that produced by radionuclide decay in comets and asteroids in 1.05 × 10 9 yr. For each amino acid the radiolysis degree and the radioracemization degree were measured by differential scanning calorimetry and by optical rotatory dispersion spectroscopy. From these measurements, a radiolysis rate constant k dsc and a radioracemization rate constant k rac were determined for each amino acid and extrapolated to a dose of 14 MGy, which corresponds to the expected total dose delivered by natural radionuclide decay to all the organic molecules present in comets and asteroids in 4.6 × 10 9 yr, the age of the Solar system.It is shown that all the amino acids studied can survive a radiation dose of 14 MGy, although certain fractions of them are lost as a result of radiolytic processes. Similarly, the radioracemization process accompanying the radiolysis does not extinguish the initial enantiomeric enrichment. Knowledge of the radiolysis and radioracemization rate constants may permit the calculation of the original concentrations of the amino acids at the time of the formation of the Solar system, starting from the concentration found today in carbonaceous chondrites. For some amino acids the concentration in the pre-solar nebula could have been up to 6 times higher than that currently observed in meteorites. The preservation of an original enatiomeric excess is also expected. This study adds experimental support to the suggestion that amino acids were formed in the interstellar medium and in chiral excess and then were incorporated into comets and asteroids at the epoch of Solar system formation.

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Section: Resultsmentioning

confidence: 99%

Amino acids in comets and meteorites: stability under gamma radiation and preservation of the enantiomeric excess

Iglesias‐Groth¹,

Cataldo²,

Ursini³

et al. 2010

Monthly Notices of the Royal Astronomical Society

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“…It is well known that high energy radiation plays against preservation of chirality and the phenomenon occurring in these conditions is called radioracemization (Cataldo, 2007a(Cataldo, , 2007bCataldo et al, 2008). Only in rare cases the radiation may play a chiral amplification role (Cataldo et al, 2007(Cataldo et al, , 2009a(Cataldo et al, , 2009b). Fig.…”

Section: Alanine and Leucine Solid State Radiolysismentioning

confidence: 96%

Solid state radiolysis of amino acids in an astrochemical perspective

Cataldo

Angelini

Iglesias‐Groth

et al. 2011

Radiation Physics and Chemistry

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“…The Lewis acid catalyzed carbocationic isomerization polymerization of β-pinene has been explored since the 1950s [ 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 ]. A number of Lewis acids, such as AlCl 3 , AlBr 3 , EtAlCl 2 , Et 2 AlCl, BiCl 3 , SbCl 3 , ZrCl 4 , BF 3 , TiCl 4 , TiCl 3 (O i Pr), SnCl 4 , and ZnCl 2 , and different reaction conditions were used in attempts to carry out the polymerization of β-pinene.…”

Section: Introductionmentioning

confidence: 99%

Highly Efficient Cationic Polymerization of β-Pinene, a Bio-Based, Renewable Olefin, with TiCl4 Catalyst from Cryogenic to Energy-Saving Room Temperature Conditions

Verebélyi

Szabó

Réti

et al. 2023

IJMS

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Polymers based on renewable monomers are projected to have a significant role in the sustainable economy, even in the near future. Undoubtedly, the cationically polymerizable β-pinene, available in considerable quantities, is one of the most promising bio-based monomers for such purposes. In the course of our systematic investigations related to the catalytic activity of TiCl4 on the cationic polymerization of this natural olefin, it was found that the 2-chloro-2,4,4-trimethylpentane (TMPCl)/TiCl4/N,N,N′,N′-tetramethylethylenediamine (TMEDA) initiating system induced efficient polymerization in dichloromethane (DCM)/hexane (Hx) mixture at both −78 °C and room temperature. At −78 °C, 100% monomer conversion was observed within 40 min, resulting in poly(β-pinene) with relatively high Mn (5500 g/mol). The molecular weight distributions (MWD) were uniformly shifted towards higher molecular weights (MW) in these polymerizations as long as monomer was present in the reaction mixture. However, chain–chain coupling took place after reaching 100% conversion, i.e., under monomer-starved conditions, resulting in considerable molecular weight increase and MWD broadening at −78 °C. At room temperature, the polymerization rate was lower, but chain coupling did not occur. The addition of a second feed of monomer in the polymerization system led to increasing conversion and polymers with higher MWs at both temperatures. 1H NMR spectra of the formed polymers indicated high in-chain double-bond contents. To overcome the polarity decrease by raising the temperature, polymerizations were also carried out in pure DCM at room temperature and at −20 °C. In both cases, rapid polymerization occurred with nearly quantitative yields, leading to poly(β-pinene)s with Mns in the range of 2000 g/mol. Strikingly, polymerization by TiCl4 alone, i.e., without any additive, also occurred with near complete conversion at room temperature within a few minutes, attributed to initiation by adventitious protic impurities. These results convincingly prove that highly efficient carbocationic polymerization of the renewable β-pinene can be accomplished with TiCl4 as catalyst under both cryogenic conditions, applied widely for carbocationic polymerizations, and the environmentally benign, energy-saving room temperature, i.e., without any additive and cooling or heating. These findings enable TiCl4-catalyzed eco-friendly manufacturing of poly(β-pinene)s, which can be utilized in various applications, and in addition, subsequent derivatizations could result in a range of high-added-value products.

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A Study on the Optically Active Polymer Poly‐β‐pinene

Cited by 22 publications

References 13 publications

Amino acids in comets and meteorites: stability under gamma radiation and preservation of the enantiomeric excess

Amino acids in comets and meteorites: stability under gamma radiation and preservation of the enantiomeric excess

Solid state radiolysis of amino acids in an astrochemical perspective

Highly Efficient Cationic Polymerization of β-Pinene, a Bio-Based, Renewable Olefin, with TiCl4 Catalyst from Cryogenic to Energy-Saving Room Temperature Conditions

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