N pyrolysis

Lyon, R.E. and Walters, R.N., Pyrolysis combustion flow calorimetry, J. Anal. Appl. Pyrolysis, 2004, 71, 27-46. 

Thermal Volatilization Analysis n (pyrolysis analysis, TVA) Ramp heating of a plastic with passage of the evolved volatiles through one or more chemical detectors, sometimes with intervening, controlled-temperature, vapor-condensing traps. TVA is a powerful technique when coupled with Thermogravimetric Analysis. 

Fig. 4.24 Heat of immersion of a carbon (prepared by pyrolysis of Saran Polymer A) in different liquids at 300 K. The liquids for points 1-6 were (I) methanol (2) benzene (3) n-hexane (4) 3-methyl benzene (5) 2,2-dimethyl butane (6) 2,2,4-trimethyl pentane. The abscissae represent the molar volumes of the liquids. (Redrawn from the original diagram of Barton, Beswick and Harrison. " )...

An excess of crotonaldehyde or aUphatic, ahcyhc, and aromatic hydrocarbons and their derivatives is used as a solvent to produce compounds of molecular weights of 1000—5000 (25—28). After removal of unreacted components and solvent, the adduct referred to as polyester is decomposed in acidic media or by pyrolysis (29—36). Proper operation of acidic decomposition can give high yields of pure /n j ,/n7 j -2,4-hexadienoic acid, whereas the pyrolysis gives a mixture of isomers that must be converted to the pure trans,trans form. The thermal decomposition is carried out in the presence of alkaU or amine catalysts. A simultaneous codistillation of the sorbic acid as it forms and the component used as the solvent can simplify the process scheme. The catalyst remains in the reaction batch. Suitable solvents and entraining agents include most inert Hquids that bod at 200—300°C, eg, aUphatic hydrocarbons. When the polyester is spHt thermally at 170—180°C and the sorbic acid is distilled direcdy with the solvent, production and purification can be combined in a single step. The solvent can be reused after removal of the sorbic acid (34). The isomeric mixture can be converted to the thermodynamically more stable trans,trans form in the presence of iodine, alkaU, or sulfuric or hydrochloric acid (37,38). 

Another important use of a-pinene is the hydrogenation to i j -pinane (21). One use of the i j -pinane is based on oxidation to cis- and /n j -pinane hydroperoxide and their subsequent catalytic reduction to cis- and /n j -pinanol (22 and 23) in about an 80 20 ratio (53,54). Pyrolysis of the i j -pinanol is an important route to linalool overall the yield of linalool (3) from a-pinene is about 30%. Linalool can be readily isomerized to nerol and geraniol using an ortho vanadate catalyst (55). Because the isomerization is an equiUbrium process, use of borate esters in the process improves the yield of nerol and geraniol to as high as 90% (56). 

Isoprene (2-methyl-1,3-butadiene) can be telomerized in diethylamine with / -butyUithium as the catalyst to a mixture of A/,N-diethylneryl- and geranylamines. Oxidation of the amines with hydrogen peroxide gives the amine oxides, which, by the Meisenheimer rearrangement and subsequent pyrolysis, produce linalool in an overall yield of about 70% (127—129). 

Another important process for linalool manufacture is the pyrolysis of i j -pinanol, which is produced from a-pinene. The a-pinene is hydrogenated to (73 -pinane, which is then oxidized to cis- and /n j -pinane hydroperoxide. Catalytic reduction of the hydroperoxides gives cis- and /n j -pinanol, which are then fractionally distilled subsequendy the i j -pinanol is thermally isomerized to linalool. Overall, the yield of linalool from a-pinene is estimated to be about 30%. 

Chlorinated by-products of ethylene oxychlorination typically include 1,1,2-trichloroethane chloral [75-87-6] (trichloroacetaldehyde) trichloroethylene [7901-6]-, 1,1-dichloroethane cis- and /n j -l,2-dichloroethylenes [156-59-2 and 156-60-5]-, 1,1-dichloroethylene [75-35-4] (vinyhdene chloride) 2-chloroethanol [107-07-3]-, ethyl chloride vinyl chloride mono-, di-, tri-, and tetrachloromethanes (methyl chloride [74-87-3], methylene chloride [75-09-2], chloroform, and carbon tetrachloride [56-23-5])-, and higher boiling compounds. The production of these compounds should be minimized to lower raw material costs, lessen the task of EDC purification, prevent fouling in the pyrolysis reactor, and minimize by-product handling and disposal. Of particular concern is chloral, because it polymerizes in the presence of strong acids. Chloral must be removed to prevent the formation of soflds which can foul and clog operating lines and controls (78). 

The intermediacy of N-arylbenzotriazoles in the formation of carbazoles from o-anilinobenzenediazonium salts has already been mentioned in Section 3.03.2.3. The parallel conversion of 1,4- and 1,5-diphenyl-l,2,3-triazoles to 3-phenylindole with minor amounts of the 2-isomer has been effected by flash vacuum pyrolysis (Scheme 106a) (75JCS Pl)l). Similar treatment of 1,3,5- or 3,4,5-triphenyl-1,2,4-triazole provides 1,3-diphenylisoindole (Scheme 106b) <75JCS(P1)12>. 

The isomerization of oxaziridines (1) to acid amides with migration of a substituent from C to N is a general reaction and is always observed when no other reactions predominate under the relatively harsh conditions (heating to above 150 °C or photolysis). Even then one can make acid amide formation the main reaction by working at 300 °C (57JA5739) and by dilution techniques. For example, caprolactam (63) is formed in 88% yield by flash pyrolysis of oxaziridine (52) at about 300 °C, whereas decomposition of (52) at lower temperatures gives almost no (63) (77JPR274). 

A -1,3,4-Oxadiazolin-2-imine, N-phenyl-pyrolysis, 6, 437 A -1,3,4-Oxadiazolin-5-imines IR spectra, 6, 429 A -1,3,4-Oxadiazolin-2-imines hydrolysis, 6, 438... 

Pyrazolo[3,4-c]pyrazole, tetrahydro-rearrangement, 5, 250 Pyrazolo[4,3-c]pyrazole, tetraaryl-electrophilic substitution, 6, 1035 oxidation, 6, 1034-1035 reduction, 6, 1035 vacuum pyrolysis, 6, 1035 Pyrazolo[ 1,2-n]pyrazole-1,5-diones synthesis, 6, 991 Pyrazolo[ 1,2-n]pyrazoles reactions, 6, 1038 ring opening, 6, 983... 

Thiophene, bromotetrahydromethyl-pyrolysis, 3, 902 Thiophene, 5-t-butyl-2-methyl-dealkylation, 4, 800 Thiophene, chloro-polymerization, 4, 758 reaction with n-butyllithium, 4, 831 synthesis, 4, 835, 882, 933 Thiophene, 2-chloromercurio-reactions... 

Diels-Alder reactions, 4, 842 flash vapour phase pyrolysis, 4, 846 reactions with 6-dimethylaminofuKenov, 4, 844 reactions with JV,n-diphenylnitrone, 4, 841 reactions with mesitonitrile oxide, 4, 841 structure, 4, 715, 725 synthesis, 4, 725, 767-769, 930 theoretical methods, 4, 3 tricarbonyl iron complexes, 4, 847 dipole moments, 4, 716 n-directing effect, 4, 44 2,5-disubstituted synthesis, 4, 116-117 from l,3-dithiolylium-4-olates, 6, 826 electrocyclization, 4, 748-750 electron bombardment, 4, 739 electronic deformation, 4, 722-723 electronic structure, 4, 715 electrophilic substitution, 4, 43, 44, 717-719, 751 directing effects, 4, 752-753 fluorescence spectra, 4, 735-736 fluorinated derivatives, 4, 679 H NMR, 4, 731 Friedel-Crafts acylation, 4, 777 with fused six-membered heterocyclic rings, 4, 973-1036 fused small rings structure, 4, 720-721 gas phase UV spectrum, 4, 734 H NMR, 4, 7, 728-731, 939 solvent effects, 4, 730 substituent constants, 4, 731 halo... 

Ketene [463-51-4] M 42.0, b 127-130 , d 1.093, n 1.441. Prepared by pyrolysis of acetic anhydride. Purified by passage through a trap at -75° and collected in a liquid-nitrogen-cooled trap. Ethylene was removed by evacuating the ethylene in an isopentane-liquid-nitrogen slush pack at -160°. Stored at room temperature in a suitable container in the dark. See diketene on p. 209. 

This polymer first appeared commercially in 1965 (Parylene N Union Carbide). It is prepared by a sequence of reactions initiated by the pyrolysis of p-xylene at 950°C in the presence of steam to give the cyclic dimer. This, when pyrolysed at 550°C, yields monomeric p-xylylene. When the vapour of the monomer condenses on a cool surface it polymerises and the polymer may be stripped off as a free film. This is claimed to have a service life of 10 years at 220°C, and the main interest in it is as a dielectric film. A monochloro-substituted polymer (Parylene C) is also available. With both Parylene materials the polymers have molecular weights of the order of 500 000. 

The procedure is a modification of that published. Methylenecyclohexane has been prepared by the pyrolysis of N,N-dimethyl-l-methylcyclohexylamine oxide, N,N,N-trimethyl-l-methylcyclohexylammonium hydroxide, N,N-dimethylcyclo-hexylmethylamine oxide, and N,N,N-trimethylcyclohexylmethyl-ammoniumhydroxide. It has also been obtained from the pyrolysis of cyclohexylmethyl acetate and of cyclohexylideneacetic acid and from the dehydrohalogenation of cyclohexylmethyl iodide. ... 

There still remains to be settled the point of attachment of the a-aminopropionic acid side-chain in leucenol. As the latter is unaffected by boiling hydrobromic or hydriodic acid, an ether linkage at C in 3-hydroxypyridone-4 is unlikely and as the side-chain is eliminated by either pyrolysis or the action of alkali C for the location, as suggested by Kostermanns see mimosine below) is improbable. The balance of evidence seems to be in favour of attachment to the N-atom and additional data supporting this view have been provided by Adams and Jones. ... 

Pyrolysis of pyrazolines, 102, 103 Pyrrolidine enamines, 412 2a-(N-pyrrolidinylcyanomininomethy 1) -A-nor-5a-androstan-17ftol, 415... 

A variety of acyclic and cyclic S-N compounds decompose at moderate temperatures (100-150°C) with the formal loss of a symmetrical NSN fragment, but this molecule has never been detected. The lowest energy isomer, linear NNS, is generated by flash vacuum pyrolysis of 5-phenyl-1,2,3,4-thiatriazole (Eq. 5.1). ... 

C/o50-carboranes are the most numerous and the most stable of the carboranes. They are colourless volatile liquids or solids (depending on mol wt.) and can be prepared from an alkyne and a borane by pyrolysis, or by reaction in a silent electric discharge. This route, which generally gives mixtures, is particularly useful for small c/o50-carboranes (n = 5-7) and for some intermediate c/ow-carboranes (n = 8-11), e.g. 

In the chloro series, the compounds to be considered are N=S-C1, cyc/o-N3S3Cl3, cyclo-N3S3CI3O3, and cyc/o-N4S4Cl2 the ionic compounds [S4N3]" "C1 and [cyc/o-N2S3Cl]+Cl and [c<2/ <2-N(SCl)2] [BCl4] together with various isomeric oxo- and fluoro-chloro derivatives. Thi-azyl chloride, NSCl, is best obtained by pyrolysis of the trimer in vacuum at 100°. It can also be made by the reaction of CI2 on NSF (note that... 

The products of these double-alkylation sequences in the j8-carboline series, 2,9-dialkyl-j8-carbolinium salts, react with base to yield the corresponding quaternary hydroxides. Pyrolysis of the salts leads to dealkylation at the pyr-N with the production of the corresponding ind-A-alkyl-j8-carbohnes. ... 

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