Methoxylation of α-pinene over poly(vinyl alcohol) containing sulfonic acid groups

Abstract

a b s t r a c tThe methoxylation of ␣-pinene was studied using poly(vinyl alcohol) (PVA) containing sulfonic acid groups as catalysts. These groups were introduced by the direct reaction between -OH groups of PVA and sulfosuccinic acid (SSA). Poly(vinyl alcohol) catalysts were prepared using sulfosuccinic acid by varying the amount of SSA (5-40 mol%). It was observed that the amount of acid sites increases with amount of SSA. It was also observed that the diffusivity of ␣-pinene through the polymeric catalysts decreases with the increase of crosslinking degree.The conversion of ␣-pinene increases when the amount of sulfosuccinic acid used in the polymer crosslinking is increased from 5% to 40%. However, when the crosslinking degree increases from 20% to 40%, the conversion of ␣-pinene increases only slightly.Good values of selectivity to ␣-terpinyl methyl ether (about 60% near complete conversion) were obtained over poly(vinyl alcohol) with sulfonic acid groups.Catalytic stability of the PVA SSA20 was evaluated by performing consecutive batch runs with the same catalyst sample. After the third batch it was observed a stabilisation of the initial activity.A kinetic model was developed assuming that the ␣-pinene is consumed according to the parallel reaction network. Since the concentration profiles of the reagent and the products do not exhibit any pronounced initial inductive period, the external and internal diffusion of the reagents and products on the catalyst were not considered. It was observed that the kinetic model fits experimental concentration data quite well.

Potassium Alum [KAl(SO4)2∙12H2O] solid catalyst for effective and selective methoxylation production of alpha-pinene ether products

“…Turpentine is a valuable and renewable natural resource widely used in the medical industry, for the synthesis of new important chemicals foruse as cosmetic, flavours, fragrances, and pharmaceuticals sectors as well as in the synthesis of chemical intermediates [3]. Thus, α-Pinene is considered a versatile building block for the synthesis of high-value added chemicals, mainly through catalytic processes, such as hydration [4,5,6,7,8,9], isomerization [10,11], epoxidation and pinene oxide isomerization [12,13,14], esterification [15,16], and etherification [17,18,19,20,21,22], among others can be applied to obtain a wide variety of added value products.…”

Review: Poly(vinyl alcohol) Functionalizations and Applications

“…In 2009 a Spanish school reported the use of PVA bearing sulfonic acid function (Fig. 13) as catalyst in the methoxylation of α-pinene [113] , the esterification of fatty acids [114] , and the hydrolysis of sucrose [115] . The esterification of PVA (MW = 72 kDa) with sulfosuccinic acid leading to polymeric catalyst ( Fig.…”

SnBr2-catalyzed highly selective synthesis of alkyl ethers from monoterpenes

“…Various approaches taking advantage of heterogeneous catalysis have been proposed, involving highly selective catalysts toward the desired products, which should have a good reusability, low toxicity, simple handling, and easy disposal. Various heterogeneous catalysts have been used for the synthesis of α-terpinyl alkyl ethers, such as zeolites, ions or acid-activated clays, Amberlyst resins, sulfonated silica, micro and mesoporous carbons, poly(vinyl alcohol) containing sulfonic acid groups [15][16][17][18][19][20]. Despite the high conversions achieved (ca.…”

“…Despite the high conversions achieved (ca. 90%), in all these processes, the selectivity of α-terpinyl methyl ether was close to 60%, due to the formation of products resulting from carbon skeletal rearrangement, such as olefins or other ethers [15][16][17][18][19][20].…”