Valorization of cigarette butts for synthesis of levulinic acid as top value-added chemicals

Abstract

Unprecedented in the literature, levulinic acid (LA), one of the top value-added intermediates of chemical industry, is obtained from cigarette butts as cellulose feedstock by means of a one-pot hydrothermal process carried out at 200 °C for 2 h and catalysed by phosphoric acid. The protocol avoids the use of more aggressive and toxic H2SO4 and HCl, that are generally employed on several cellulose sources (e.g. sludge paper), thus minimizing corrosion phenomena of plants. Neither chemical pre-treatment of butts nor specific purification procedure of LA are required. Notably, by simply modifying acid catalyst (e.g. using CH3COOH), another top value-added fine chemical such as 5-hydroxymethylfuraldehyde (HMF) is obtained, thus widening the scope of the method. Being cigarette filters a waste available in quantities of megatonnes per year, they represent an unlimited at no cost source of cellulose, thus enabling the up-scale to an industrial level of LA production.

Biobased Approach for Synthesis of Polymers and Sustainable Formulation of Industrial Hardeners

“…The yield 0. 620 g (62% w/w of soy husks) was obtained with a calibration curve and levulinic acid was identified by comparison of the MS spectrum with that reported in the literature [18]. GC/MS (70 eV) m/z (relative intensity): 116 (M+, 3.06), 56 (29.58), 43 (100) (see Supplementary Materials for NMR characterization).…”

“…In the first step, in line with Circular Economy principles, a waste ligno-cellulosic biomass such as soy husks was used as a source of monosaccharides for preparing the first synthetic intermediate, which is levulinic acid. To improve the eco-sustainability of this reaction, thermal hydrolysis was conducted with Amberlyst 15 [17], a solid cation exchange resin bearing sulfonic groups that can act as a heterogeneous acid catalyst in place of the toxic and aggressive strong mineral acids H 2 SO 4 , HCl [18]. Besides limiting the corrosion of the plants, the use of the Amberlyst 15 would allow the easy recycling of the acid catalyst.…”

“…The presence of free H + ions pushes HMF to open and rearrange itself into levulinic acid (1) [18]. Levulinic acid (1) has been oxidized in succinic acid (2), using trifluoroacetic acid, to avoid the by-products due to the Baeyer-Villiger reaction; this procedure also allows the recovery of the acid catalyst [19].…”

“…This step of the reaction proceeds through a series of acid-base equilibria that lead to a series of intermediates, among which 5-Hydroxymethylfurfural (5-HMF) is the most stable. The presence of free H + ions pushes HMF to open and rearrange itself into levulinic acid (1) [18]. Levulinic acid (1) has been oxidized in succinic acid (2), using trifluoroacetic acid, to avoid the by-products due to the Baeyer-Villiger reaction; this procedure also allows the recovery of the acid catalyst [19].…”

Production of Bio-Oils and Biochars from Olive Stones: Application of Biochars to the Esterification of Oleic Acid

“…Many researchers have found that biochar can be used as an alternative adsorbent to remove different types of pollutants, such as heavy metals, nutrients, and pharmaceuticals, from aqueous solutions [ 20 ]. Many raw materials and their resulting biochars have low specific surface or low catalytic activity, so these materials are pre-treated (activated) with acids, such as sulphuric acid [ 21 ] or phosphoric acid [ 22 ]. To the best of our knowledge, biochars from olives stones have not been applied as biocatalyst so far.…”