The reaction of crotonic anhydride with scots and corsican pine investigation of kinetic profiles and determination of activation energies

Krotonik anhidrit ile Sarıçam ve Karaçamın pridin katalizatör eşliğindeki reaksiyon kinetiği incelenmiş ve başlangıç reaksiyonları için aktivasyon enerjileri tespit edilmiştir. Aktivasyon enerjileri bir çok farklı sıcaklık derecelerinin kullanılarak zaman aşaması deneylerinden elde edilen oran verilerinin Arrhenius eşitliği kullanılarak hesaplanmıştır, ilk metotta reaksiyon sabitesi (k) deneysel olarak belirlenmiş, diğer metotta ise başlangıç oranı sıfır zamanı için hesaplanmıştır. Sarıçam ve Karaçamın oran sabitesi metodu ile aktivasyon enerjisi değerleri sırasıyla 39,0 (±5.8) and 30.3 (±6.8) kJ $mol^{-1}$ olarak hesaplanmıştır. Aktivasyon enerjilerinin belirlenmesinde başlangıç oran metoduda kullanılmıştır. Sarıçam ve Karaçam örnekleri için sırasıyla 41.3 (±7.0) and 26.9 (±4.0) kJ $mol^{-1}$ değerleri elde edilmiştir. Her iki yöntemle belirlenen aktivasyon enerjisi değerleri arasında belirgin bir fark bulunamamıştır. Başlangıç reaksiyonunda pseudo first order kinetik gözlemlenmiştir, iki odun türü arasında yaklaşık 10 kJ $mol^{-1}$'lük aktivasyon enerjisi farklılığı bulunmuştur. Bu farkın sebebi bilinememiştir. Bu bilgiler reaksiyon mekanizmasının anlaşılması veya büyük ölçekli üretimlerin etkin olarak dizayn edilmesi ve benzeri konuların değerlendirilmesinde temel önem taşımaktadır.

Sarıçam ve Karaçam ile krotonik anhidrit reaksiyonu: Kinetik profillerinin incelenmesi ve aktivasyon enerjilerinin belirlenmesi

The kinetics of the reaction of crotonic anhydride with Scots pine (Pinus sylvestris) and Corsican pine (Pinus nigra) using pyridine as catalyst/solvent was investigated and activation energies for the initial reaction determined. Activation energies were calculated from the Arrhenius equation using rate data obtained from time-course experiments repeated at several temperatures. In one method, reaction constants (k) were determined experimentally, while in the other method initial rates were extrapolated at time zero. With the rate constant method, activation energy values for Scots and Corsican pine were calculated as 39.0 (±5.8) and 30.3 (±6.8) kJ $mol^{-1}$, respectively. The method of initial rate was also used to determine activation energy. Activation energies of 41.3 (±7.0) and 26.9 (±4.0) kJ $mol^{-1}$ were obtained for Scots and Corsican pine, respectively. There was no significant difference between the activation energies determined by the two methods. The initial reaction was observed to follow pseudo first-order-kinetics. A difference of ca. 10 kJ $mol^{-1}$ between the activation energies was found between the two wood species. The reason for this difference is not known. This information is of fundamental importance when considering such issues as mechanisms of reaction, or designing efficient large scale processes.

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  • Hill, C.A.S. and D. Jones. 1996a. A chemical kinetics study of thepropionic anhydride. Journal of Wood Chemistry and Technology16 (3): 235-247.
  • Hill, C.A.S. and D. Jones. 1996b. The dimensional stabilisation ofCorsican pine sapwood by reaction with carboxylic acidanhydrides. The effect of chain length. Holzforschung 50 (5): 457-462.
  • Hill, C.A.S., D. Jones, G. Strickland and N.S. Cetin. 1998. Kinetic andmechanistic aspects of the acetylation of wood with aceticanhydride. Holzforschung 52 (6): 623-629.
  • Hill, C.A.S. and S.J. Mallon. 1999. The chemical modification of Scotspine with succinic anhydride or octenyl succinic anhydride. II.Reaction kinetics. Journal of Wood Chemistry and Technology 18(3): 299-311
  • Mallon, S.J. 1999. Activation of wood with succinic anhydride and itsderivatives for composite production. PhD Thesis. University ofWales Bangor, UK, p. 163.
  • Stamm, A.J. and H. Tarkow. 1947. Dimensional Stabilisation of Wood.Journal of Colloid Chemistry, 51: 493-505.
  • West, H. 1988. Kinetics and mechanism of wood isocyanate reactions.PhD Thesis. University of Wales Bangor, UK, p. 349.
Turkish Journal of Agriculture and Forestry-Cover
  • ISSN: 1300-011X
  • Yayın Aralığı: Yılda 6 Sayı
  • Yayıncı: TÜBİTAK
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