Use of delaminated zeolites (ITQ-2) and mesoporous molecular sieves in the production of fine chemicals: Preparation of dimethylacetals and tetrahydropyranylation of alcohols and phenols

Layered Materials with Catalytic Applications: Pillared and Delaminated Zeolites from MWW Precursors

“…For instance, it is the case of the preparation of dimethylacetals and tetrahydropyranylation of alcohol and phenols using ITQ-2 delaminated zeolite as acid catalyst. The results obtained confirmed that when the reactions involved bulky reactants, ITQ-2 exhibited the highest activity owing to the combination of its disordered structure and the presence of strong and accessible acid sites into their framework (Scheme 16) [63,145]. Into this thematic, interesting acetalization processes were carried out, catalyzed by MWW delaminated materials, for the synthesis of orange blossom and apple fragrances [146].…”

“…Similarly, direct synthesis of phenylacetaldehyde glycerol acetals (2-benzyl-4-hydroxymethyl-1,3-dioxolane, 2-benzyl-5-hydroxy-1,3-dioxane) and vanillin propylene glycol acetal (2-(4-hydroxy-3-methoxyphenyl)-4-methyl-1,3-dioxolane) which are flavoring compounds with hyacinth and vanilla scent fragrances, respectively, was successfully performed by acetalization of phenylacetaldehyde and vanillin with glycerol and propylene glycol, using toluene as solvent and exfoliated zeolites as catalysts (Scheme 17). On the opposite, in the case of bulky acetals, such as 2-acetonaphthone propylene glycol acetal with blossom orange N HO HO OH CH 3 CH 3 H + C CO NH Scheme 18: Protection of hydroxyl groups by tetrahydropyranyl ethers (according to [63]). scent, geometrical constraints, imposed by the microporous channels of conventional zeolites, would be a serious inconvenient to overcome during the acetalization processes.…”

Metal Organic Frameworks as Solid Acid Catalysts for Acetalization of Aldehydes with Methanol

“…Finally, n-heptanal also showed good reactivity with very high selectivity towards the synthesis of the commercially important dimethyl acetal of heptanal that corresponds to the vegetable topnote in fragrances and also in fine chemicals. [25] The above results show that Cu 3 A C H T U N G T R E N N U N G (BTC) 2 is a general catalyst for the room temperature formation of dimethyl acetals of aldehydes. Concerning ketone acetalization the situation is less clear.…”

Cyclic Acetalization of Furfural on Porous Aluminosilicate Acid Catalysts

“…Zeolites [2] and molecular sieves [13][14] have been identified as a potential heterogeneous acid catalyst for such reaction. Aluminosilicate material was explored as active catalyst to drive the reaction where researches have been focused only on porous aluminosilicate catalysts [15].…”