Thermal properties of citronellyl diesters

Abstract

Thermal properties of linear citronellyl diesters were studied by TG/DSC/FTIR/QMS-coupled method in inert and oxidative atmospheres. The diesters decompose in one main step in inert atmosphere. As main pyrolysis products, the formation of mainly monoterpene hydrocarbons, acid anhydrides, monoacids, cyclic ketones, aldehyde fragments, carbon dioxide, and water was observed. It was indicated on the ester and O-citronellyl bonds cleavage, partial decarboxylation, and elimination of water from formed dicarboxylic acids during their pyrolysis. The decomposition in air runs in two steps. The first step was connected with the creation of monoterpene hydrocarbons, monoacids, cyclic ketones, aldehydes, carbon dioxide, carbon monoxide, and water. In the second step of decomposition, mainly carbon dioxide and water were produced. It was testified to ester and O-citronellyl bonds cleavage, partial oxygenation, and decarboxylation process of the primary formed decomposition products.

Thermal properties of neryl long-chain esters obtained under microwave irradiation

“…Also, in this decomposition stage, the evaporation of water vapor (3,600-3,740 cm -1 ) [26-30, 35, 36] and emission of carbon dioxide (670 cm -1 and 2,330-2,365 cm -1 ) [26-30, 34, 37] are indicated. At T max2 , besides the products observed at T max1 , the evaporation of an acid anhydride (signals at 900, 1,050, 1,811 and 1,870 cm -1 responsible for m C-O and C=O groups) is clearly indicated for neryl esters obtained using shorter acid chain length (succinic anhydride and glutaric anhydride) [26][27][28][29][30]. For neryl esters based on adipic acid and sebacic acid, the evaporation of an acid anhydride…”

“…The 7 and 11 membered anhydrides due to their low stability, decomposes in air losing CO 2 . In this reaction, as a main decomposition compounds, cyclic ketones are formed [26][27][28][29][30]. The formation of those compounds during decomposition of neryl esters based on adipic and sebacic acids was confirmed by the presence of absorption signals at 1,768-1,790 cm -1 (m C=O) and at 1,008-1,178 cm -1 (m C-O) on FTIR spectra [31].…”

“…Traditionally, chemically those esters are prepared in catalyzed esterification process of monoterpene alcohols with acid anhydrides or acid chlorides using large excess of terpene alcohol and often toxic solvents [13,25]. Recently, we have proposed the method of the preparation of geranyl, neryl and citronellyl diesters [26][27][28] and long-chain esters of geraniol [29,30] using butylstannoic acid as a catalyst under conventional conditions. The use of such catalyst allowed reducing the formation of by-products, using of stoichiometric amount of reagents and significantly increasing the yields of pure product which consequently reduced the production cost of flavor esters for cosmetic, laundry and perfume applications.…”

Thermal degradation of some ferrocene-containing poly(aryleneethynylene)s

“…In these spectra, apart from the characteristic bands presented above, other bands were also noticed. For example, the peaks in the range of 1610-1500 cm -1 could be asigned as the C=C stretching vibration (alkene) [22], and the ones in the range 1000-740 cm -1 would be ascribed to the out-of-plane deformation vibration of =C-H groups [24]. ).…”

TG/DSC/FTIR/QMS studies on the oxidative decomposition of terpene acrylate homopolymers

“…However, the intensity of the absorption bands was lower at T max1 than at T max2 . At T max1 , the presence of the signals responsible for the deformation vibrations of C-H (1374 and 1445 cm -1 ), the stretching vibrations of C-H (2880-2970 cm -1 ), the out-of-plane deformation vibrations of =C-H (906 cm -1 ), the stretching vibration of C=C (1627 cm -1 ), the stretching vibrations of C=O (1707-1765 cm -1 ) and the stretching vibrations of C-O Table 2 The main organic volatile decomposition products and the corresponding m/z ion values with relative intensity regarding the NIST database [36] Homopolymer Volatile decomposition products (1083-1205 cm -1 ) indicates the formation of terpene derivatives as primary decomposition products [31,32,37] which is a similar behavior to those observed for the decomposition process of geranyl and neryl acrylate homopolymers. But, lower mass loss at this stage and lower intensity in the emission of the decomposition gaseous products may indicate only on the breaking of the C-O bonds between main carbon chain and the branching initiated on the end polymer chains [22] and the partial oxidation and decarboxylation of formed species leading to the emission of CO (2110-2184 cm -1 ), CO 2 (699 and 2329-2358 cm -1 ) and H 2 O (above 3500 cm -1 ) [31,32].…”