Propyl pyrolysis

Method 3.5 Identification of Acrylic Acid and Methacrylic Acid in Acrylic Copolymers. Propylation - Pyrolysis - Gas Chromatography [41]... 

Figure 3.20 shows a pyrogram of polymethylmethacrylate copolymerised to contain 1 and 10% of acrylic or methacrylic acid. By this procedure, copolymerised acrylic or methacrylic acid has been identified in terpolymers with (a) butyl acrylate and styrene, (b) methylmethacrylate and ethyl acrylate and, (c) ethylene and propylene. A methyl methacrylate - methylstyrene - maleic acid terpolymer, when examined by this propylation - pyrolysis procedure, yielded dipropyl fumerate and a smaller amount of dipropyl maleate. 

METHOD 61 - IDENTIFICATION OF ACRYLIC ACID AND METHACRYLIC ACID IN ACRYLIC COPOLYMERS. PROPYLATION - PYROLYSIS GAS CHROMATOGRAPHY. ... 

Identification of acrylic acid and methacrylic acid in acrylic copolymers. Propylation-pyrolysis-gas chromatography... 

Propjiene [115-07-17, CH2CH=CH2, is perhaps the oldest petrochemical feedstock and is one of the principal light olefins (1) (see Feedstocks). It is used widely as an alkylation (qv) or polymer—ga soline feedstock for octane improvement (see Gasoline and other motor fuels). In addition, large quantities of propylene are used ia plastics as polypropylene, and ia chemicals, eg, acrylonitrile (qv), propylene oxide (qv), 2-propanol, and cumene (qv) (see Olefin POLYMERS,polypropylene Propyl ALCOHOLS). Propylene is produced primarily as a by-product of petroleum (qv) refining and of ethylene (qv) production by steam pyrolysis. 

Above 300°C. the effective reaction of an alkyl radical with oxygen may be Reaction 3 rather than 2 because of the reversibility of Reaction 2. If it is assumed that Reaction 3 is important at about 450°C., its rate can be estimated from the competition between pyrolysis and oxidation of alkyl radicals. Falconer and Knox (21) observed that the ratio of (pro-pene)/(ethylene) from the oxidation of propane between 435° and 475°C. increased with oxygen concentration and decreased with temperature—the apparent activation energy difference for the two reactions forming the olefins being 27 =t 5 kcal. per mole. They interpreted this result in terms of a competition between Reactions 1 and 3. The observed ratio (propene)/(ethylene) was 3.5 at 435°C. and 10 mm. of Hg pressure. If log ki(propyl) = 13.2 — 30,000/2.30RT, the value for the n-propyl radical (34), then log k3 = 8.0. If the A factor is 109-3, we derive the Arrhenius equation... 

Pyrolysis of tris(heptafluoroisopropyl)-1,2,4-triazine (329) affords bis(heptafluoroiso-propyl)acetylene and perfluorobutyronitrile, besides nitrogen (79JCS(P1)1978, 80JCS(P1)2254). The thermal fragmentation of this compound is analogous to the mass spectral fragmentation of many other 1,2,4-triazines. 

The total yield of 201 was increased and the synthesis time reduced by extracting [nC]butyric acid from its lithium salt by dry 0.1% HCl/He gas mixture and carrying out its pyrolysis at 530 °C over glass beads (equation 104). The relative reactivity of 201 to primary, secondary and tertiary alcohols (equation 105a, b, c) has been found to be as 1 0.4 0.1, respectively. Several bioactive compounds have been labelled with [nC]propyl ketene, such as carbohydrate compounds193 and IV-butyl compounds, for instance /V- 11 C]butyryl THPO, 202, and some phorbol esters192, 203, 204 and 205. 

L-Theanine is the most abundant amino acid in tea flush. Volatiles produced by pyrolysis at 180°C of (A) L-theanine, (B) (-)-epigallocatechin gallate and (C) a mixture of (A) and (B) were examined. The procedure was the same as that reported earlier for the pyrolysis of 8-carotene. The results of the GC-MS analysis are shown in Figure 4. From L-theanine alone, a large amount of N-ethyl-formamide was formed, along with ethyl amine, propyl amine, 2-pyrrolidone, N-ethyl-succinimide and l-ethyl-3,4-dehydro-pyrrol idone. 

Ravey, M. Weil, E.D. Keidar, I. Pearce, E.M. Flexible polymethane foam. II. Fire retardation by tris(l,3-dichloro-2-propyl) phosphate. Part B. Examination of the condensed phase (the pyrolysis zone). J. Appl. Polym. Sci. 1998, 68, 231-254. 

The procedure described is essentially the same as that of Buck-ley and Scaife.3 The yield has been increased from 55.5% up to 72% by using 1.3 mol eq of phthalic anhydride and by carefully controlling the pressure and cooling the receiving flask. Although 2-nitropropene has previously been prepared by pyrolysis of 2-nitro-1-propyl benzoate in 72% overall yield from 2-nitro-l-propanol,4 the present method is preferred for its preparation since the procedure is much simpler and the product is directly obtainable from 2-nitro-l-propanol without first preparing its ester. It is also applicable to the preparation of 1-nitro-l-propene (58%),5-6 2-nitro-1 -butene (82%),7 and 2-nitro-2-butene (60%).6,7 In general, aliphatic nitroolefins have the tendency to polymerize readily with alkali. 

Recycling of plastics is difficult, because of the content of the additives PBBs and PBDEs [27]. Pyrolysis of flame retardant material of printed circuit board and electronics components (laboratory scale) produces high amounts of brominated dioxins and furans (2,3,7,8-TeBDF, 29 pg/kg residue after quarts flask pyrolysis in N2/H2 atomosphere at 1100 °C) located in the condensed material. It was known that these plastics contain flame retardants to a maximum of 20 wt%. PBDEs can be extracted from plastics based on propyl-carbonate. The origin of brominated dioxins and furans detectable in propyl-carbonate extract is still to be investigated. Further recycling activities which process flame retarded plastics might produce hazardous products, an aspect that has to be investigated more closely [27]. 

This is more in line with the electron impact results and with the results from the pyroloysis of n-propyl benzene. Stevenson has since stated that the electron impact work already quoted together with some unpublished results leads to D(CH3-H) Z)(G2H5 H) ==5 1 0 7 kcal. Evidence from the pyrolysis of iodides, though possibly not very reliable, gives 6 kcal for this quantity. Accordingly a value of 96 kcal for D(C2H5 -H) can be adopted with fair confidence. This is a little lower than the value commonly adopted until recently. 

Pyrolysis of n-propyl benzene gives Z)(Ph. GH2 - G2H5) as 57 5 kcal, leading to 94 kcal for Z)(Et-H) usine the known value oi... 

Pyrolysis of ethyl radicals was found to be relatively unimportant although the reverse is true for larger alkyl radicals such as n-propyl, isobutyl and tert-butyl. Indeed, Sampson estimated that almost half the isobutane consumed gives radicals whose fate is pyrolysis [155]. On the other hand, radical—radical reactions are important and many of the minor products are believed to be formed from further reactions of ethoxy radicals formed in reaction (52)... 

More recent work has shown that, below about 200 °C, the pyrolysis of iso-propyl nitrate follows first-order kinetics. The main products are... 

Table I 4) a) shows that allyl iodide decomposes much more readily than any of those previously described. At 494 decomposition was almost 60 %, so that in order to obtain more moderate decomposition lower temperatures had to be chosen. Exps. 77-78 show the absence of any effect of iodide-pressure on the rate. The comparison of these results with Exp. 80 reveals a fourfold increase of Ai caused by a twelvefold reduction of the contact time. Exps. 84, 78, 82 and 86, carried out at the lower temperature of about 356° again show Aj as independent of the iodide pressure. Comparing Exp. 84 with Exps. 78, 82 and 86, and the latter with Exps. 89 and 81, we see also that the rise of Aj with diminishing contact time has become less marked— if not altogether negligible. With a further lowering of the temperature to about 298° (Exps. 83, 79, 85, 88) the dependence of Ai on contact time becomes quite imperceptible. Thus with decreasing temperature the kinetics of the reaction appear to conform increasingly well to the monomolecular scheme. Extrapolating the rate of pyrolysis of -propyl iodide down to 298°, the ratio of Aj for -propyl allyl can be calculated at about i 14000.

We may use the observations listed above to derive in some cases the temperature coefficients of the rate of pyrolysis and hence the activation energy of the reaction. For w-propyl iodide and n-butyl iodide we have sufficiently reliable data for two temperatures from which we calculate for -propyl 0 = 52 kcal. and for -butyl Q = 53 kcal. This lends support to the value of similar magnitude, Q — 55 kcal., obtained from the otherwise less reliable Exps. 3, 4, and 6, 7, 8 for ethyl iodide. 

Pyrrolo[l,2-a]indolequinones were prepared also by cyclization reactions. One of them involves copper-catalyzed pyrolysis of 2-azido-5-methoxy-6-methyl-3-(2,4-pentadienyl)-l,4-benzoquinone to give compound 45 (87JOC3956). The second pyrrole ring was also formed from a 2-hydroxy-propyl side chain of an indolo-4,7-dione (80JOC5057). Benzo analogs were prepared in a Friedel-Crafts reaction from either phthalic anhydride (67TL765) or 2-pyrrolidinylcarbonyl chloride (86H2797). 

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