Secondary Pyrolysis Products Research Articles

Theoretical study on the catalytic pyrolysis mechanism of polyethylene terephthalate dimer

ABSTRACT In this paper, the density functional theory of B3P86/6–31++G(d,p) method was used to study the mechanism of the catalytic pyrolysis reactions of PET dimer. The calculated results show that the reaction energy barrier for calcium oxide to capture a proton on carboxyl group (at 112.6 kJ/mol) is lower than that on alkyl group (at 153.3 ~ 170.0 kJ/mol), which is more conducive to decarboxylation reaction. The protons provided by the acid catalyst attack the oxygen atoms of the C=O bond of PET main chain to form the cationic intermediate, and then the cleavage reaction occurs on the Calkyl-O bond, of which the bond dissociation energy is the lowest at 46.9 ~ 62.4 kJ/mol. Compared with pure pyrolysis, catalysts have little effect on the components of initial pyrolysis products, but it has effects on the components of secondary pyrolysis products of PET. The addition of catalysts can change the components of secondary pyrolysis products by changing the optimal reaction path of degradation. During the reaction processes, both alkaline and acidic catalysts can reduce the reaction energy barriers of the main elementary reactions to a certain extent (from 251.3 ~ 264.6 kJ/mol to 112.6 ~ 170.0 and 46.9 ~ 169.1 kJ/mol, respectively), making the reactions easier to proceed.

Mechanism study on pyrolysis interaction between cellulose, hemicellulose, and lignin based on photoionization time-of-flight mass spectrometer (PI-TOF-MS) analysis

It is critical to accurately reveal the interactions between biomass components for the selective preparation and directional exploitation of pyrolysis products. The rapid, simultaneous capture of the full mass spectrum of intermediates is advantageous for elucidating the interaction mechanism. To depict the real complicated pyrolysis reactions, a simplified coupled cross-pyrolysis process among the biomass components is examined. The interaction was studied by the examination of offline product distribution, bio-oil, and bio-gas composition, as well as the evolution of pyrolysis intermediates using an online photoionization time-of-flight mass spectrometer (PI-TOF-MS). Results indicate that the interaction only affects product distribution, rather than creating a new pyrolysis reaction pathway. The cracking of glycosidic bonds during low-temperature cellulose depolymerization provides hydrogen donor (H∙) and hydroxyl donor (OH∙) for the primary cleavage of hemicellulose and lignin. It increases the ring opening of C5 of hemicellulose and the cleavage of lignin's phenylpropane side chains, promoting the production of aliphatic compounds, guaiac-based phenols, and syringe-based phenols. CO cracking on the side chain of phenylpropane provides donors for the ring opening of cellulose’s secondary pyrolysis products, further promoting the production of aliphatic chains. High temperatures hasten the fragmentation of partial aliphatic chains and the demethylation of phenols, providing donors and molecular fragments (methyl and methoxy, etc.) for the aromatization of linear molecules and encouraging the generation of aromatic compounds. The study's findings will help to improve knowledge of the biomass pyrolysis interaction and be used as a reference for targeted biomass utilization and the optimization of catalytic pyrolysis strategies.

Testing Flight-like Pyrolysis Gas Chromatography-Mass Spectrometry as Performed by the Mars Organic Molecule Analyzer Onboard the ExoMars 2020 Rover on Oxia Planum Analog Samples.

The Mars Organic Molecule Analyzer (MOMA) onboard the ExoMars 2020 rover (to be landed in March 2021) utilizes pyrolysis gas chromatography-mass spectrometry (GC-MS) with the aim to detect organic molecules in martian (sub-) surface materials. Pyrolysis, however, may thermally destroy and transform organic matter depending on the temperature and nature of the molecules, thus altering the original molecular signatures. In this study, we tested MOMA flight-like pyrolysis GC-MS without the addition of perchlorates on well-characterized natural mineralogical analog samples for Oxia Planum, the designated ExoMars 2020 landing site. Experiments were performed on an iron-rich shale (that is rich in Fe-Mg-smectites) and an opaline chert, with known organic matter compositions, to test pyrolytic effects related to heating in the MOMA oven. Two hydrocarbon standards (n-octadecane and phytane) were also analyzed. The experiments show that during stepwise pyrolysis (300°C, 500°C, and 700°C), (1) low-molecular-weight hydrocarbon biomarkers (such as acyclic isoprenoids and aryl isoprenoids) can be analyzed intact, (2) discrimination between free and complex molecules (macromolecules) is principally possible, (3) secondary pyrolysis products and carryover may affect the 500°C and 700°C runs, and (4) the type of the organic matter (functionalized vs. defunctionalized) governs the pyrolysis outcome rather than the difference in mineralogy. Although pyrosynthesis reactions and carryover clearly have to be considered in data interpretation, our results demonstrate that pyrolysis GC-MS onboard MOMA operated under favorable conditions (e.g., no perchlorates) will be capable of providing important structural information on organic matter found on Mars, particularly when used in conjunction with other techniques on MOMA, including derivatization and thermochemolysis GC-MS and laser desorption/ionization-MS.

Pyrolysate composition and silylation efficiency in analytical pyrolysis of glucans as a function of pyrolysis time

The pyrolytic behaviour of two oligosaccharides – cellobiose and cellohexose – was studied using reactive pyrolysis-GC/MS with in situ hexamethyldisilazane derivatisation. Pyrolysis was conducted in a sealed vessel at various times ranging from 0.2 to 60 min. Semi-quantitative calculations were carried out on integrated peak areas to obtain information on derivatisation efficiency and composition of the pyrolysate as a function of pyrolysis time. The results were compared with a previous work by us in which glucose and cellulose were studied with the same procedure. The relative areas of anhydrosugars were found to decrease with the increase of the degree of polymerisation of the substrate, while the derivatisation efficiency showed an opposite trend. The results were explained by considering the role of both the sealed environment and water molecules freed during the pyrolysis process. We hypothesised that higher amounts of water were released from glucans with low degrees of polymerization, hindering both secondary pyrolysis reactions and derivatisation efficiency. Glucans with high degrees of polymerization, on the contrary, showed high signals of secondary pyrolysis products, consistent with a lower amount of water and the formation of a liquid phase.

Pyrolytic Processing of Cellulose-Containing Wastes from Food Industry Plants

A possible thermal process for disposal of wastes from the brewing and sugar industries was studied. Information on the yields of secondary pyrolysis products (pyrogas, pyroliquid, solid residue) as a function of changes in the processing parameters was obtained. Pyrogas consisting of H2, CO, CO2, CH4, and saturated and unsaturated C2–C5 fractions had a heat of combustion of 1.79 and 1.65 MJ/m3 for spent grain and sugar-beet pulp, respectively. A universal unit allowing any type of waste with various quantities of added hydrocarbon waste to be processed was developed.

Pyrolysis of tert-Butyl tert-Butanethiosulfinate, t-BuS(O)St-Bu: A Computational Perspective of the Decomposition Pathways

A systematic theoretical study has been performed on the low pressure thermal decomposition pathways of t-BuS(O)St-Bu using the CCSD(T)/cc-pV(D+d)Z//B3LYP/6-311++G(2d,2p), CCSD(T)/cc-pV(D+d)Z//PBEPBE/6-311++G(2d,2p), and G3B3 level of theories. Rate constants for the unimolecular decomposition pathways are calculated using Rice−Ramsperger−Kassel−Marcus (RRKM) theory. On the basis of the experimental observation and theoretical predictions, the pyrolysis channels are considered as primary and secondary pyrolysis reactions. The primary decomposition via a five-membered transition state leads to the formation of tert-butanethiosulfoxylic acid (t-BuSSOH) and 2-methylpropene (C4H8) almost exclusively having low-pressure limit rate constant k(1)(0) = 4.67 × 10(−6)T(−4.67) exp(−11.64 kcal mol(−1)/RT) cm3 mol(−1) s(−1) (T = 500−800 K). The primary decomposition via a six-membered transition state is also identified, and that leads to the tert-butanethiosulfinic acid t-BuS(OH)S, which is the branched chain isomer of t-BuSSOH. The formation of t-BuSSOH is thermodynamically as well as kinetically favorable over t-BuS(OH)S formation, and therefore the second product could not be found experimentally. Furthermore, calculation on secondary pyrolysis pathways involving the decomposition of t-BuSSOH leads to the formation of 1-oxatrisulfane (trans-HSSOH and cis-HSSOH) and their branched isomer S(SH)OH. These three secondary product formation rates are competitive, but thermodynamics do not favor the formation of the branched isomer. Among the secondary pyrolysis products, trans-HSSOH is the most stable one, and its formation rate constant at low pressure is calculated to be k(3)(0) = 5.49 × 10(28)T(−10.70) exp(−36.22 kcal mol(−1)/RT) cm3 mol(−1) s(−1) (T = 800−1500 K). Finally, the secondary pyrolysis pathway from less stable product t-BuS(OH)S is also predicted, and that leads to trans-HSSOH and cis-HSSOH products with almost equal rates. A bond-order analysis using Wiberg bond indexes obtained by natural bond orbital (NBO) calculation predicts that the primary and secondary pyrolysis of t-BuS(O)St-Bu occur via E1-like mechanism.

Pilot-Scale Gasification of Corn Stover, Switchgrass, Wheat Straw, and Wood: 2. Identification of Global Chemistry Using Multivariate Curve Resolution Techniques

A pilot-scale study was conducted to examine the effect of the steam-to-biomass ratio, the gasification temperature, and the thermal cracker temperature for Vermont wood, wheat straw, switchgrass, and corn stover on the formation and speciation of tars. This study is divided into two parts; the first paper detailed the processing conditions and gives quantitative information on low-molecular-weight species. This paper, which is the second part of this study, uses multivariate curve resolution techniques to correlate process variables with the mass spectra gathered during the study to (1) identify the global chemistry of the system and (2) to identify differences or similarities of the product gas streams for each feedstock. Three main groups of products were identified statistically: (1) primary and secondary pyrolysis products (e.g., guaiacol, furfural), (2) cracking products (e.g., phenol, cresol), and (3) polynuclear aromatic hydrocarbons (PAHs). Our findings support known global reaction mechanisms that delineate the formation of the more-refractory PAHs, whereby oxygenated pyrolysis products are cracked into smaller fragments that contain less oxygen. These crack further into small hydrocarbons and radicals that undergo molecular weight growth to produce PAHs. The results from this statistical analysis indicate that, at high temperatures, where PAHs dominate, there is little variation observed between the feedstocks.

Reactions of 2-(pyrrol-1-yl)benzyl radicals and related species under flash vacuum pyrolysis conditions

2-(Pyrrol-1-yl)phenoxyl, aminyl, thiophenoxyl and benzyl radicals 2a-2d, respectively, were generated in the gas-phase under flash vacuum pyrolysis conditions. In all cases except the phenoxyl, cyclisation took place providing acceptable synthetic routes to the fused heterocycles 11, 14 and 15, respectively. Only sigmatropic rearrangement products were isolated, in low yields, from the phenoxyl 2a. The pyrrolo[1,2-a]benzimidazole 11 adopts the 1H-tautomer exclusively in chloroform solution. Electrophilic substitution reactions of pyrrolo[2,1-b]benzothiophene 14 were studied, including protonation, deuterium exchange, Vilsmeier formylation and reaction with dimethyl acetylenedicarboxylate. 2-(2,5-Diarylpyrrol-1-yl)thiophenoxyl, phenoxyl and aminyl radicals 23a-f, were also generated in the gas-phase under similar conditions. The thiophenoxyls 23a/b gave extremely complex pyrolysate mixtures in which primary cyclisation products were formed by attack of the radical at the pyrrrole ring and attack at the ipso-, ortho- and meta- positions of the aryl ring. Secondary pyrolysis products were obtained by specific sigmatropic shifts of the N-aryl group. The 2,5-di(thien-2-yl)thiophenoxyl radical 23c gave the pyrrolobenzothiazole 31c as the only cyclisation product in low yield. FVP of the phenoxyl and aminyl radical generators 26d and 26f, respectively, gave 3-arylpyrrolo[1,2-f]phenanthridines 46d and 46f, respectively, by a hydrogen transfer-cyclisation mechanism.

Pyrolysis and THM reactions of melamine and its resins

Melamine resins and a melamine polyester copolymer have been investigated with pyrolysis-GC/MS and thermally assisted hydrolysis and methylation (THM). Conventional pyrolysis yields characteristic volatile products only at temperatures above 500 °C and hexamethylenetetramine is the main product. A series of methylated melamines and secondary pyrolysis products were also found. THM yields high amounts of methylated melamines and therefore provides a sensitive method for the detection of melamine in resins and copolymers. Deduced from this results a preparative approach for the synthesis of methylated melamines with aqueous tetramethylammonium hydroxide solution was successfully developed.

Synthesis, thermal reactivity and kinetics of substituted [(benzoyl)(phenylcarbamoyl)methylene]triphenylphosphoranes and their thiocarbamoyl analogues

A range of 16 substituted benzoyl/arylcarbamoyl and benzoyl/arylthiocarbamoyl stabilised ylides have been prepared. They are found under conditions of flash vacuum pyrolysis to fragment giving a benzoyl ylide and aryl isocyanate or isothiocyanate accompanied in some cases by secondary pyrolysis products. Kinetic studies show the thiocarbamoyl ylides to react consistently faster than their carbamoyl analogues and substituent effects suggest a polar cyclic transition state, which involves attack by the benzoyl oxygen on the carbamoyl/thiocarbamoyl NH.

Ageing behaviour and analytical pyrolysis characterisation of diterpenic resins used as art materials: Manila copal and sandarac

Artificial indoor and outdoor exposure conditions have been applied in order to investigate the photo-ageing behaviour of two natural resins once used as art materials. Copals and sandarac consist of free labdane diterpenoids and of a highly cross-linked fraction of polycommunic acid. To determine the nature and the composition of the cross-linked fraction, pyrolysis is required. Thermally assisted hydrolysis and methylation, coupled with gas chromatography–mass spectrometry (THM-GC/MS), has been used to identify the acidic compounds. Many secondary pyrolysis products have been recognised and distinguished from the original resin components. Further details on the composition and ageing behaviour of Manila copal and sandarac have been obtained from Fourier transform infrared spectroscopy (FTIR), size exclusion chromatography (SEC) and direct temperature-resolved mass spectrometry (DTMS). During ageing, cross-linking and cleavage reactions were found to affect largely the chemical structure of the two resins, together with minor degradation processes such as isomerisation, defunctionalisation and oxidation.

Effect of Porous and Nonporous Carbonaceous Substrates on Polystyrene Thermal Degradation during Fast CO2 Laser Heating

To investigate the effect of porosity on elution of volatiles from a devolatilizing coal particle under pulverized coal combustion (PCC) type heating rate conditions, polystyrene was doped into porous model char (Spherocarb) particles and also coated on the surface of nonporous model char (Glassy Carbon) particles. Particles of approximately 80 μm (± 10 μm) diameter were then individually handpicked. These 80 μm diameter particles were heated to a temperature in the range of 1200−2000 K in 32 ms by means of two converging CO2 laser beams. The eluted products were analyzed by combined gas chromatography/mass spectrometry (GC/MS). The evolved product information was used to construct yield curves. These yield curves were compared to a simple first-order rate law prediction. It was observed that while the styrene yield profile was predicted satisfactorily in the case of nonporous Glassy Carbon, styrene evolution rates were approximately four times slower than predicted in the case of porous Spherocarb. Also, the ratio of secondary pyrolysis products of polystyrene (benzene, toluene, etc.) to a primary pyrolysis product (styrene) was approximately four times higher in the case of Spherocarb than in the Glassy Carbon case. Both findings strongly suggest the presence of transport limitations in porous Spherocarb under PCC-type heating rate conditions.

Formation of long-chain ketones in archaeological pottery vessels by pyrolysis of acyl lipids

Studies of organic residues preserved in unglazed archaeological pottery have revealed the presence of homologous series of long-chain ketones containing 29–35 carbon atoms. The C 31, C 33 and C 35 ketones are particularly abundant and exhibit a distinct monomidal distribution. The presence of long-chain ketones in potsherds is usually ascribed to the absorption of epicuticular waxes into the pottery fabric during the cooking of leafy vegetables. However, compound specific stable carbon isotope ( δ 13C) analyses of the individual lipids present in the potsherd extracts, in combination with detailed structural information, indicates that these ketones do not derive from plant waxes. Isotopic and structural analysis of the fatty acids, which always co-occur with the ketones, suggest that a precursor-product relationship exists. Micro-scale pyrolysis of a range of free fatty acids and triacylglycerols in the presence of various inorganic matrices was undertaken in exploring the possibility of an abiological route to the formation of the ketones. Depending on the pyrolysis conditions employed, substantial yields of long mid-chain ketones were formed which were structurally and isotopically congruent to those observed in the ancient potsherds. The ketones are formed by ketonic decarboxylation (a type of head to head condensation reaction), probably involving fatty acid metal salts as intermediates, the metal being provided by the inorganic matrix. Apart from the abundant long mid-chain ketones various other products such as methylketones, methyl esters, alkanes, alk-1-enes and homologous series of minor ketones are formed as secondary pyrolysis products. These latter products are not found in the pottery probably due to less vigorous thermal conditions achieved during the original use of the vessel compared with those attained in the laboratory pyrolysis experiments. Evidence for this comes from the formation of the fatty acid methyl esters which are only produced under the most forcing of pyrolysis conditions.

Pyrolysis chemical ionization mass spectrometry of cellulose ethers

AbstractPyrolysis ammonia chemical ionization (PyCI) mass spectrometry was performed on hy‐droxyethyl‐, hydroxypropyl‐,methyl‐, hydroxypropylmethyl‐, and ethylhydroxyethyl cel‐luloses. The mass peaks in the PyCI mass spectra of these cellulose ethers could be assigned to the ions of pyrolytic dissociation products which form via the [2 + 2 + 2] cycloreversion and the Ei elimination pyrolysis pathway. Structural information about the residual amount of nonderivatized cellulose, the relative chain length distributions of the substituents in hydroxyalkyl celluloses, and the end‐capping of hydroxyalkyl substituents by alkyl groups in the mixed cellulose ethers is obtained. Interference of secondary pyrolysis products in the PyCI mass spectra is found to be of minor importance, especially in the lower mass regions. © 1995 John Wiley & Sons, Inc.

Pyrolysis/GC/MS Analysis of 1-[(2'-carboxyl)pyrrolidinyl]-1-deoxy-D-fructose (Proline Amadori Compound)

Pyrolysis/GC/MS was applied to the study of primary and secondary pyrolysis products of 1-[(2'-carboxy)pyrrolidinyl]-1-deoxy-D-fructose (proline Amadori compound). The Amadori product was pyrolyzed on a ribbon probe at 150, 200, 250, 300, an 350 o C for 10 s. The main products formed under these conditions were 1-(1'-pyrrolidinyl)-2-propanone, 2-hydroxy-1-(1'-pyrrolidinyl)-1-buten-3-one, and 2,3-dihydro-3,5-dihydroxy-6-methyl-4(H)-pyran-4-one in addition to acetic acid and pyrrolidine. To produce secondary pyrolysis products, the Amadori compound was pyrolyzed at 250 o C in a quartz tube for 20 s; 14 secondary pyrolysis products were identified

Characterization of aromatic hydrocarbon formation from pyrolysis of polyethylene-polystyrene mixtures

Design and operating parameters, and cause and effect relationships among feedstocks and products in the pyrolysis of waste polymers are needed if this method of processing is to be used for energy recovery from waste plastics. The purpose of this study was to quantify the effect of various operating factors for the pyrolysis of common polymeric wastes. Experiments were performed using a conventional retort tube as a batch reactor. The operating factors considered were temperature and reaction time at constant heating rate. High density polyethylene (PE) and polystyrene (PS), the most common plastic waste in Korea, were used singly and in mixture. The pyrolysis time for maximum oil production from a PE-PS mixture was shorter than in the case of PE alone, showing an enhancement effect from the PS. The maximum gas production time from PE-PS mixtures was shorter than for PE alone at 500° C; above 600° C, this does not occur. Small aromatic compounds (which can be valuable) are produced at maximum with an 1:1 mixture of PE and PS at 600° C, showing the possibility of process control for the maximum recovery of desirable pyrolysis products. The maximum yield of toluene, xylene, styrene, and 1-propenyl benzene were 8.6, 8.9, 51.0 and 7.4 wt.% of feed for pyrolysis PS at 700° C, respectively. For naphthalene, it was at 700° C with 1:1 PE:PS (by wt.). The maximum recovery was 1.3 wt.%. Diels-Alder theory can explain the formation of aromatic compounds in the pyrolysis products. The yield of these secondary pyrolysis products can be controlled by reaction time, pyrolysis temperature and mixing ratio of plastic wastes in the pyrolysis feed.

Qualitative analysis of chlorolignins and lignosulphonates in pulp mill effluents entering the river Rhine using pyrolysis—mass spectrometry and pyrolysis—gas chromatography/mass spectrometry

Macromolecular chlorolignins and lignosulphonates have been analysed in effluents from five pulp mills discharging on the river Rhine. Analytical techniques used were ultrafiltration, pyrolysis—mass spectrometry and pyrolysis—gas chromatography / mass spectrometry. The average organically bound chlorine content was 19 mg/l, with a maximum value of 68 mg/l for the pulp mill Cellulose de Strasburg. The annual discharge of organically bound chlorine (AOX) and of dissolved organic carbon (DOC) of these five mills was calculated to be 2100 tonnes AOX and 33 000 tonnes DOC, respectively. This would account for 90% of the AOX load and 10% of the DOC load of the river Rhine. Evidence for the existence of two chlorolignin classes, aromatic chlorolignins and aliphatic chlorolignins, was obtained. Monochloroguaiacol is the most abundant structural specific aromatic chlorolignin pyrolysis product. Methyl chloride is a major chlorine containing pyrolysis product, probably originating from aliphatic chlorolignins. Sulphur dioxide is a major pyrolysis product of lignosulphonates, and possibly can be used for the specific quantitative determination of lignosulphonates in river water. Radical recombination reactions of methyl radicals and other primary pyrolysis radicals play an important role in these samples, leading to several secondary pyrolysis products. The presence of lignosulphonates in the salt or acid form has an important effect on the pyrolysis process. Methyl chloride can probably be quantified with the reference compound tetramethylammonium chloride. The macromolecular compositions of these effluents show many similarities, but also significant differences, presumably reflecting the use of different wood types, pulping and bleaching conditions at the time of sampling.

Cellulose pyrolysis kinetics and char formation mechanism

The pyrolysis of cellulose was studied by electrically heating in helium single strips (0.75 cm×2.5 cm) of low ash (<0.07%) predried filter paper (≈0.01 cm thick) supported inside a folded wire mesh heating element mounted in a sealed vessel. The samples were rapidly brought to a desired temperature, held there for a desired time and then rapidly cooled. Extents of conversion to volatiles, measured by weighing samples before and after experiments of known duration, were determined as a function of residence time (0.2–75,600 s), final temperature (250–1,000°C), heating rate (400–10,000°C/s), and ambient pressure (0.0005–1 atm). Pyrolysis kinetics was determined by nonisothermal techniques to account for substantial reaction occurring during sample heat-up and cool-down. All of the cellulose was converted to volatiles without char formation, except when an extended heating period at a low temperature (e.g., an hour or longer at 250°C) preceded the pyrolysis at higher temperatures. The latter procedure resulted in char yields of about 2% by weight of the original cellulose. The kinetics data are well described by a single-reaction first-order decomposition model with an activation energy of 33.4 kcal/mole and a frequency factor of 6.79×10 9 s −1 . The correlation is slightly improved by use of a multiple-reaction model based on a set of independent parallel first-order reactions represented by a Gaussian distribution of activation energies with a mean of 37.0 kcal/mole and a standard deviation of 1.1 kcal/mole. Selected experiments at reduced pressures (0.0005 atm), elevated heating rates (10,000°C/s), or both resulted in rate constants smaller than those obtained at 400°C/s and 1 atm. The results indicate that the residence time of volatile products within the pyrolyzing cellulose matrix is extremely important in determining conversion. Suggested pathways for cellulose pyrolysis that are consistent with these findings and with much of the pertinent literature involve primary decomposition to an oxygen-rich intermediate (probably levoglucosan) which then participates in three processes to extents depending on experimental conditions: (a) direct escape from the decomposing material into the ambient gas; (b) polymerization, cross-linking and cracking to form char and (c) pyrolysis to smaller volatiles some of which inhibit the char formation in (b) or autocatalyze (c). Accordingly, char is not a primary product, and the yield of char is zero for extremely short residence times of the primary products within the matrix of the decomposing material or for conditions that permit complete inhibition of char formation by secondary pyrolysis products.

Thermal degradation of 3-deoxy- D- erythro-hexosulose

3-Deoxy- D- erythro-hexosulose is less stable than normal carbohydrates and polymerizes within the range 100–200°. The polymerization is accompanied by dehydration, fission, and rearrangement reactions which produce water, furan derivatives, carbonyl compounds of low molecular weight, saccharinic acid, carbon dioxide, and carbon monoxide. Heating at higher temperatures results in charring of the polymeric material and further dehydration, fission, and disproportionation reactions which provide a variety of secondary pyrolysis products. The dehydration reactions are catalyzed by the addition of zinc chloride, and the fission reactions by the addition of sodium carbonate.