Cyclopentanone pyrolysis

Carbenes are known intermediates in the thermolytic or photolytic decomposition of the lithium or sodium salts of tosylhydrazones, which, for endocyclic carbenes, results in ring contraction when the elimination of / - or y-hydrogens is impeded. Simple cyclobutanes generally cannot be prepared by this route from monocyclic cyclopentanone tosylhydrazones. However, the lithium salt of bicyclo[2.2.1]heptan-7-one tosylhydrazone gave bicyclo[3.2.0]hept-l-ene (4) as the major product (74%) by vacuum pyrolysis at 185 JC/20 Torr, together with bicyclo[2.2.1]heptane (14%) and tricyclo[2.2.1.02,7]heptane (12%) in 80% overall yield.67... 

FIGURE 15.14 FTIR monitored online during aTG-FTIR experiment (this means several hundreds of FTIR spectra are taken) of PA 66-GF/MPP enables the identification of volatile pyrolysis products (H20, NH3, C02, cyclopentanone, amines, and hydrocarbons) at distinct stages of the decomposition and the investigation of the product release rates. 

The pyrolysis liquid of Nylon 6,6 contains alkadienes and cycloalkenes in addition to cyclopentanone in the gasoline boiling range, furthermore this fraction also involves hexanedinitrile and even alkylamines. The components of the diesel oil boiling range... 

A number of reactions of metal salts can be rationalized in terms of the formation of a carbanion adjacent to the carboxylate. Dibasic metals such as calcium bring two carboxylate units close to each other so that the carbanion formed adjacent to one carboxylate may attack the carbonyl of the other. Thus pyrolysis of calcium acetate affords propanone (acetone) (Scheme 3.62). A similar reaction is found in the pyrolytic cyclization of some dicarboxylic acid anhydrides. Heating Cg and dicarboxylic acids gives cyclopentanones and cyclohexanones... 

The pyrolysis of tetramethylenediazirine in the gas phase is a first-order reaction yielding only cyclopentene and nitrogen. Similarly, the treatment of the tosylhydrazone of cyclopentanone with base under aprotic conditions yields cyclopentene as the only hydrocarbon product. Photolysis of this diazirine yields cyclopentene as the principal hydrocarbon product (99.2%), but very small quantities of bicyclo[2,1,0]-pentane (0.3%) and methylenecyclobutane (0.1%) are also formed. In addition, about 0.5% of another hydrocarbon was detected but not identified. Its early position of the chromatogram indicates that it may be a fragmentation product. 

The kinetics of the decomposition of cyclopentanone are complex and definitely differ from those of cyclobutanone as well as from those of other ketones. In spite of the uncertain mechanism, it may be stated that this reaction is, in many respects, similar to the pyrolysis of cyclopentane. In both cases, dehydrogenation and rupture of the ring take place as simultaneous processes. 

Substituted cyclopentanones are available by pyrolysis of siloxyvinylcyclopropanes and hydrolysis of the intermediate silyl enol ethers, e.g. formation of 6 and 7. ... 

The chemistry of synthetic jasmine materials was given an enormous boost in the 1930s when Nylon 66 was launched as a product. Nylon 66 is a polyamide prepared using adipoyl chloride and hexamethylenetetramine as monomers. The 66 in the name refers to the fact that there are 6 carbons in each type of unit that lies between the amide links in the polymer chain. Thus, adipic acid is the key feedstock for Nylon 66 and the introduction of the latter meant that the former became a basic chemical commodity. Pyrolysis of the calcium or barium salt of adipic acid produces cyclopentanone, and so the availability of large quantities of the acid meant that the ketone could also be prepared at low cost. 

In general, the classes of compounds Included furfurals (9.4Z), phenols (2.5Z), methoxyphenols (16.9Z), cyclic compounds such as methyl cyclopentanones (10.8Z), methoxy benzenes (3.8Z), and the substituted propane tentatively Identified for the peak at scan number 1207 (36.8Z). Although the compound eluting at scan 1207 Is by far In the highest concentration. Insufficient Information Is available from Its spectrum to allow a reasonable Identification. The base peak observed Is 75amu, and a 115 amu Ion Is also present at 40Z abundance. These results, which are preliminary, differ somewhat from other published compositions of pyrolysis oils (3. 7-8). Future work will be required to verify the compositions observed above. 

It has been shown that synthetic zeolites such as ZSM-5 can be used to convert oxygenated compounds derived from biomass materials into hydrocarbons which can be used as fuels or chemicals feedstocks (1,2,3,4). However, the pyrolysis oils obtained from biomass materials by different thermal and thermochemical processes (5,6) showed poor hydrocarbon yields and high tar content when contacted over ZSM-5 zeolite catalysts at high temperatures (7,8). Since the pyrolysis oils are composed of a wide variety of oxygenated compounds such as cyclopentanone, cyclopentenone, furfural, phenol, carbohydrate and carboxylic acid derivatives (9,10) it is difficult to point out exactly which family of compounds is contributing more to the observed tar and to the rapid deactivation of the catalysts. Catalytic studies on model compounds which are usually found in the biomass pyrolysis oils are therefore primordial in order to determine the best catalytic system for the up-grading of pyrolysis oils to useful hydrocarbon products. The reactions of some phenolic, carbonyl and carboxylic acid derivatives over ZSM-5 catalysts are already... 

The presence of cyclopentanone, hexamethylenediamine, and cyclic monomer among the pyrolysis products of Ny66 was early recognized. Recently MS studies suggested the occurrence of a j8-CH hydrogen transfer process (Eq. 5.3), leaving unexplained the presence of cyclopentanone. 

The structure of this compound suggests that the ion at m/z 209 may originate from further thermal degradation of the primary pyrolysis compounds (molar mass 226), possessing cyclopentanone and amino chain ends, which are very reactive species and immediately react to produce Shiff-bases by water elimination (Scheme 5.6b). The monomeric oligomer also reacts... 

Iq the case of pyrolysis under vacuum at 400°C of the mixed polyamide produced by polycondensation of caprolactam and hexamethylene-adipamide, as well as the mixed polyamide obtained from hexamethylene-adipamide, e-caprolactam, and hexamethylenesebacamide [15, 16], the following products were detected in the gas phase by mass spectroscopic analysis carbon monoxide, carbon dioxide, cyclopentanone, water, various hydrocarbons (methane, ethane, propane, butane, ethylene, butenes). Ammonia and other nitrogen compounds were not detected in the gas phase. All the nitrogen remains in the solid residue [15-18]. The... 

A detailed analysis of the products of thermal destruction of poly-hexamethyleneadipamide and polycaproamide is given in [22]. The polyamides were heated at 300-305°C in a stream of dry nitrogen. The gaseous pyrolysis products contain large amounts of NH3, CO2, H2O, small amounts of n-hexylamine, n-pentylamine, and cyclopentanone. Analysis of the hydrolysis products of the residue obtained after pyrolysis of the polyamides permitted the authors to propose a scheme for the process. 

Attempts to assign the band at 290 m/x to cyclopentanone have given a negative result (the spectra of cyclopentanone exhibit a band at 2730 A on account of the carbonyl group). The band at 280-290 m/x may be explained by the formation of substituted indoles in the pyrolysis of polyhexamethyleneadipamide [24]. 

The gas-phase pyrolysis of chrysanthanyl acetate affords a mixture of acyclic unsaturated aldehydes and enol acetates, all of which are probably derived from the 1,4-biradical (625). ° Results are also discussed of the pyrolyses of chrysanthanyl alcohol and other emio-pinen-7-ols. The photochemical free radical reaction between P-pinene and t-butyl hypochlorite has been studied, and the oxidative addition of cyclopentanone to p-pinene in the presence of cupric salts has been observed. Photoaddition of iV-nitrosopiperidine to P-pinene at — 40 gave the a-piperidinium... 

The construction of a cyclopentanone unit through treatment of a ketone with 1-lithiocyclopropyl phenyl sulphide and pyrolysis of the vinylcyclopropane (10) so... 

Class hardened polyamides, upon pyrolysis at 350 °C, produced cyclopentanone from polyamide 6,6 and e-caprolactam from polyamide-6 [44]. 

The fast pyrolysis decomposition of cellulose starts at temperatures as low as 150°C. Pyrolysis of cellulose below 300°C results in the formation of carboxyl, carbonyl, and hydro peroxide groups, elimination of water and production of carbon monoxide and carbon dioxide as well as char residue (Evans and Milne, 1987). Therefore low pyrolysis temperatures will produce low yields of organic liquid yields. Fast pyrolysis of cellulose, above 300°C, results in liquid yields up to 80 wt.%. Cellulose initially decomposes to form activated cellulose (Bradbury et al., 1979). Activated cellulose has two parallel reaction pathways, depolymerization and fragmentation (ring scission). The main products from each reaction pathway are rather different as ring scission produces hydroxyacetaldehyde, linear carbonyls, linear alcohols, esters, and other related products (Bradbury et al., 1979 Zhu and Lu, 2010 Lin et al., 2009) and depolymerization produces monomeric anhydrosugars, furans, cyclopentanones, and pyrans and other related products (Bradbury et al., 1979 Zhu and Lu, 2010 Lin et al., 2009). Each reaction pathway is independent and is influenced by pyrolysis temperature and residence time (Bradbury et al., 1979). 

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