Steam distillation, of volatile aldehydes

Aldehydes, general procedure (3). A solution of nilnie 1 (1 mol) in EtOAc saturated with HO gas al 0°C is added to a solution ol SnCl2 (1.1 mol) in EtOAc previously saturated wlh HCI at 0°C. After several hours at 0°C the aldimine complex (R.CHNH2 3 SnCle separated as pale yellow prisms. The complex was filtered, washed with EtjO and dried over KOH under vacuum to afford a pure sample of 2. Steam distillation of 2 gave aldehyde 3 in the distlRate if the aldehyde was volatile. Alternatively, the aldehyde was extracted from the residue of the steam distillate... 

Semicarbazones of volatile aldehydes may be hydrolyzed by steam distillation in the presence of phthalic anhydride/ A synthetic route for aromatic aldehydes involves the hydrolysis of semicarbazones which have been prepared by the interaction of dithio acids and semicarbazide hydrochloride in pyridine solution/ ... 

Identification and quantitative analyses of 25 compounds in steam distillates of burley tobacco stalk were accomplished. Compounds included twelve C,-C. compounds that were probable fatty acid oxidation products and 13 compounds >C that varied in origin. The latter included oxidation products of fatty acids, a C. prenyl pyrophosphate metabolite, and biodegradation products of carotenoids and chlorophyll. About 1/3 of the distillate mass was accounted for. Burley tobacco stalk headspace volatiles were also studied. When compared to the steam distillate, the headspace contained greater concentrations of sesquiterpenoids but lower concentrations of C, and C aldehydes and alcohols. Volatiles in steam distillates of tobacco stalk were not quantitatively different in a fungal resistant and a fungal sensitive variety of tobacco. Yield comparisons were made of headspace volatiles from tobacco and wheat. 

Our previous results (15) on the composition of wheat SDE volatiles are shown in Table IV. These results support a direct precursor-product relationship between a fatty acid and a specific steam distilled volatile compound, because hexanal and trans 2-nonenal (which presumably originate from their linoleic acid precursor C18 2) account for a larger proportion of the total oil from steam distillates of tobacco stalk than is the case for wheat plants (cf. Table I and Table IV). On the other hand, trans 2-hexenal and the sum of nonadien-aldehydes and alcohols (which presumably originate from linolenic acid C18 3) account for a larger proportion of the oil of wheat than of tobacco stalk. 

Essential oils are volatile, odorous principles consisting of terpene alcohols, aldehydes, ketones and esters (>90%) and/or phenylpropane derivatives. Aetherolea are soluble in ethanol, but only to a very limited extent in water. They are mostly obtained by steam distillation of plant material. 

Definition Volatile oil from steam distillation of fresh root of Levisticum officinale] contains d-a-terpineol, butyl dihydrophthalides, butyl tetrahydrophthalides, coumarin, aldehydes, acetic acid, isovaleric acid... 

Essences of pink and white fresh guava obtained by direct extraction of flesh juices with dichloromethane revealed that the total amount of Cs aldehydes, alcohols, and acids comprised 20 and 44% of the essence of fresh white and pink guavas, respectively [49]. The flavour of the Costa Rican guava has been described as sweet with strong fruity, woody-spicy, and floral notes [53]. One hundred and seventy-three volatile compounds were isolated by simultaneous steam distillation-solvent extraction. The terpenes and terpenic derivatives were found in this fruit in major concentrations and were strong contributors to tropical fruit notes (Fig. 8.1). The aliphatic esters contributed much to its typical flavour. 

The aqueous solution (about 180 cc.) of non-volatile products from the steam distillation is cooled to room temperatime, filtered to remove a little insoluble material, and then cooled in ice water. The somewhat impure azelaic half aldehyde (3.33 g., or 76%) which separates is collected, dried, and extracted with 400 cc. of boiling light petroleum (b.p. 40-60°) in which all but 0.6 g., identified as the trimer of the aldehyde acid, dissolves. When the petroleum solution is cooled in ice-salt mixture, the semialdehyde separates as plates which, after several re-crystallizations from 50 parts of warm water, yields 1.6 g. of pure azelaic aldehyde acid as colorless rhombic plates melting at 38°. 

Cassia Oil occurs as a yellow or brown liquid having the characteristic odor and taste of cassia cinnamon. It is the volatile oil obtained by steam distillation from the leaves and twigs of Cinnamomum cassia Blume (Fam. Lauraceae), rectified by distillation, and consisting mainly of cinnamic aldehyde. Upon aging or exposure to air it darkens and thickens. It is soluble in glacial acetic acid and in alcohol. 

Our first separation method involved running the simultaneous steam distillation extraction under 100 mm vacuum in order to minimize heat effects. This was followed by extraction under atmospheric pressure in order to get more complete recovery. This atmospheric extraction was run for 10 days, using a fresh hatch of solvent each day (68-69). Approximately 10 times as much material was collected each day at atmospheric pressure as was collected under vacuum. Since Schultz, et. al. (70) showed that many non-water-soluble alcohols, esters, aldehydes, and ketones can he recovered by this system in less than 3 hours, the collection of a large amount of material after 10 days is indicative of a very complex and probably dynamic system. Gas chromatograms for these extracts (68.) and some compound identifications (69.) have been reported. (Other reports on the identification of volatiles from protein hydrolysates are given In references 71-75). Prelminary results have shown that the vacuum extracts are more attractive for the Medfly than the atmospheric ones. 

The volatiles of fresh pineapple (Ananas comosus [L] Merr.) crown, pulp and intact fmit were studied by capillary gas chromatography and capillary gas chromatography-mass spectrometry. The fnjit was sampled using dynamic headspace sampling and vacuum steam distillation-extraction. Analyses showed that the crown contains Cg aldehydes and alcohols while the pulp and intact fruit are characterized by a diverse assortment of esters, h rocarbons, alcohols and carbonyl compounds. Odor unit values, calculated from odor threshold and concentration data, indicate that the following compounds are important contributors to fresh pineapple aroma 2,5-dimethyl-4-hydroxy-3(2H)-furanone, methyl 2-methybutanoate, ethyl 2-methylbutanoate, ethyl acetate, ethyl hexanoate, ethyl butanoate, ethyl 2-methylpropanoate, methyl hexanoate and methyl butanoate. 

Finally, oU is steam distilled under a high vacuum to strip out trace amounts of FFAs, aldehydes, ketones, and other volatile compounds, among others, thus producing a bland oil. During deodorization, the oil is heated to 230-250°C under a vacuum of 1—4- mm Hg. 

There is only one report in the literature concerning Astragalus essential oil. Miyazawa in 1987 [214] has studied the volatile flavour of "Astragali radix" (the root of A.membramceus, that has a good note and a dry green mild fruity odor), obtained by steam distillation under atmosferic pressure of the macerated roots twenty-two components have been identified by GC, GC-MS, IR and NMR analyses. They include 9 dimethylesters of dicarboxilic acids, 14 methylesters of fatty acids, 2 aldehydes, 1 ketone, 4 alcohols and 1 acid. Methyl palmitate is the main component (22.0 %), followed by dimethyl azelate (16.2 %), a compound with a fhiity-winey odor such as the dimethyl esters of dicarboxilic acids. 

A grouping of the compounds showed that aldehydes and terpenoids, respectively, made up 41-57% and 6-21% of the volatiles in root tissue, 19-24% and 46-58% of leaf volatiles and 6-14% and 81-91% of the stem volatiles (Mazza and Cottrell, 1999). P-Myrcene was the predominant aerial part volatile among Echinacea species (Table 8.4), but in roots, it was found only in E. pallida. An ethanol extract of the achene followed by steam distillation resulted in a P-myrcene content of 6.8% and... 

Oil of Peppermint. Col perm in Mintec. Steam-distilled, volatile oil from fresh flowering plant Mentha piperita L, Labiatae. The Japanese oil, also known as oil of Poho, is the liq portion remaining after the separation of menthol from the oil of Mentha arvensts L., Labiatae. Constit Not less than 50% total menthol including 5 -9% esters ealed as menthyl acetate menthyl isovalerate, menthone, inactive pinene, /-limonene, cadinene, phellandrene, some acetaldehyde, isovaleric aldehyde, amyl alcohol, dimethyl sulfide. 

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