Insight into the mechanism of secondary reactions in cellulose pyrolysis: interactions between levoglucosan and acetic acid

The UV absorption spectrum of benzylchlorocarbene, generated by laser flash photolysis of 3-chloro-3- benzyldiazirine, has been observed in the 290-330 nm range. The lifetime of this species, 18 ns at 25°C, is determined by the rate of the 1,2-H migration to produce chlorostyrenes. Quenching rate constants of this carbene by acetic acid and tetramethylethylene have been measured. Comparison of this kinetic data with the quantitative analysis of the products obtained under continuous irradiation gives further insight into the mechanisms of carbene-acetic acid reactions.

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Insight into Acetic Acid Synthesis from the Reaction of CH4 and CO2

ACS Catalysis ◽

10.1021/acscatal.0c05492 ◽

2021 ◽

Vol 11 (6) ◽

pp. 3384-3401

Author(s):

Chunyan Tu ◽

Xiaowa Nie ◽

Jingguang G. Chen

Keyword(s):

Acetic Acid ◽

Acid Synthesis ◽

Insight Into

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Interaction between Acetic Acid and Glycerol: A Model for Secondary Reactions during Holocellulose Pyrolysis

The Journal of Physical Chemistry A ◽

10.1021/acs.jpca.8b11264 ◽

2018 ◽

Vol 123 (3) ◽

pp. 674-681 ◽

Cited By ~ 5

Author(s):

Bin Hu ◽

Qiang Lu ◽

Yu-ting Wu ◽

Ji Liu ◽

Kai Li ◽

...

Keyword(s):

Acetic Acid ◽

Secondary Reactions

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I. Contributions to the history of the opium alkaloids.— Part V

Proceedings of the Royal Society of London ◽

10.1098/rspl.1871.0054 ◽

1872 ◽

Vol 20 (130-138) ◽

pp. 277-289

Keyword(s):

Acetic Acid ◽

Hydrochloric Acid ◽

Glacial Acetic Acid ◽

Ethereal Extract ◽

Large Excess ◽

Opium Alkaloids ◽

Slight Excess ◽

Secondary Reactions ◽

History Of ◽

Crystalline Mass

In Part IV . of these researches reasons have been adduced for the following general conclusions, viz. that codeia and morphia are capable of forming polymerides (with the elimination of methyl in the case of codeia is some instances), which yield derivatives containing certainly not less than C 68 , and probably not less than C 130 (C 72 and C 144 in the case of those codeia derivatives where methyl has not been eliminated). Experiments now in progress tend to show that the formulae of codeia and morphia are really double of those formerly ascribed to these bases i, e . are C 30 H 42 N 2 O 6 and C 30 H 42 N 2 O 6 respectively, the proof of which is (as will be shown in a subsequent communication) that the first products of the action of hydrochloric acid on these bases appear to ‘contain chlorine and carbon in the proportions C 36 and Cl, C 34 and Cl respectively, instead of C 18 and Cl, C 17 and Cl. It might be anticipated, therefore, that intermediate polymerides might be form ed containing respectively :— Morphia series. Monomorphia.. C 34 H 38 N 206 Dimorphia . . . . C 68 H 70 N 4 O 12 Trimorphia.. . . C 102 H 104 N 6 O 18 Tetramorphia.. C 136 H 152 N 8 O 24 Codeia series. C 36 H 42 N 2 O 6 . . . Monocodeia. C 72 H 84 N 4 O 12 . . Dicodeia. C 108 H 126 N 6 O 6 . . Tricodeia. C 144 H 168 N 8 O 24 . . Tetracodeia. In the case of codeia these anticipations have been verified. In order to obtain these supposed polymerides before their alteration by secondary reactions, the action of acids other than a hydro acids was examined. Acetic acid seemed a probable agent for purpose ; but no appreciable quantity of any thing different from in codeia was obtained after sixty-four hours’ digestion a t 100° of one part this base with three parts of glacial acetic acid. On precipitation of product by Na 2 CO 3 in large excess, extraction with ether, and agitation of the ethereal extract with HCl, a crystalline mass was obtained while developed a smell of acetic acid on standing in contact with a slight excess of HCl ; but on analysis this gave numbers agreeing with those required codeia hydrochlorate, and from it nothing different from codeia could't obtained ; probably therefore only a trace of acetyl-codeia was formed.

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Considerations on Structure of Natural Rubber Vulcanizates

Rubber Chemistry and Technology ◽

10.5254/1.3547206 ◽

1968 ◽

Vol 41 (3) ◽

pp. 659-668 ◽

Cited By ~ 3

Author(s):

H. Westlinning ◽

S. Wolff

Keyword(s):

Chain Length ◽

Crosslink Density ◽

Chemical Structure ◽

Structural Features ◽

Polymer Modification ◽

Kinetic Measurements ◽

Secondary Reactions ◽

Ring Structures ◽

Natural Rubber Vulcanizates ◽

Insight Into

Abstract Deep insight into the chemistry of vulcanization, its kinetics, and network structures have been provided by the elucidation of reactions of mono and diolefins with sulfur and accelerators, primarily at NRPRA, and the kinetic measurements of transformation of vulcanizing agents with 1,5-polyenes by Scheele and co-workers at the Kautschuk Institute der Technischen Hochschule, Hannover. It is now established that both accelerated and unaccelerated vulcanization of 1,5-polyenes with sulfur begins with formation of polysulfide crosslinks. As sulfur disappearance and formation of polysulfide proceed, secondary reactions participate increasingly. These involve a series of transformations of the crosslinks originally formed. This leads to a continual change in chain length of crosslinks, in their chemical constitution, and in structural features of the polymer. Figure 1 shows schematically the results of sulfur vulcanization. Crosslinks consist of mono, di, or polysulfide structures, depending on vulcanization time and temperature. As polysulfide bonds disappear, the polymer is modified by the appearance of monosulfidic ring structures and conjugated double bonds in the chain. Secondary reactions may change the crosslink density of the vulcanizate. There are three possibilities: shortening of the crosslink chain length can proceed (a) without change in, (b) with decreasing, or (c) with increasing, crosslink density. Which occurs must be determined for each system. For each polymer the density of crosslinking, its chemical structure, and the extent of polymer modification determine physical, chemical, and technological properties of the vulcanizate.

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Distinguishing primary and secondary reactions of cellulose pyrolysis

Bioresource Technology ◽

10.1016/j.biortech.2011.02.018 ◽

2011 ◽

Vol 102 (8) ◽

pp. 5265-5269 ◽

Cited By ~ 188

Author(s):

Pushkaraj R. Patwardhan ◽

Dustin L. Dalluge ◽

Brent H. Shanks ◽

Robert C. Brown

Keyword(s):

Cellulose Pyrolysis ◽

Secondary Reactions

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Oxidative Decomposition of the Ozonide of Butadiene Rubber

Rubber Chemistry and Technology ◽

10.5254/1.3542387 ◽

1959 ◽

Vol 32 (1) ◽

pp. 288-294 ◽

Cited By ~ 1

Author(s):

A. I. Yakubchik ◽

N. G. Kasatkina ◽

G. I. Demidova ◽

G. B. Fedorova

Keyword(s):

Hydrogen Peroxide ◽

Acetic Acid ◽

Levulinic Acid ◽

Butadiene Rubber ◽

Double Bonds ◽

Oxidative Decomposition ◽

Mild Conditions ◽

Oxidative Breakdown ◽

Secondary Reactions ◽

Methylene Group

Abstract 1. Among the products of oxidative decomposition with acetyl hydroperoxide of the ozonide of butadiene rubber (prepared at 5°) are levulinic, formic, succinic, 1,2,4-butanetricarboxylic, 1,2,3-propanetricarboxylic and l,x,y,6-hexanetetracarboxylic acids. Levulinic acid could be formed by isomerization of 1,4-1)2-1,4-chains of the rubber macromolecule and by partial decarboxylation of β-ketoadipic acid, as well as by the peroxy-formate rearrangement in presence of acetyl hydroperoxide. 1,2,3-Propanetricarboxylic acid is more likely to be formed from 1,4-1,4-chains branched at the α -methylene group, or from 1,4-1,2-1,4-chains in which the double bonds had undergone suitable rearrangement, rather than as a result of secondary reactions during oxidative breakdown of the ozonide. 1,2,3-Propanetricarboxylic acid was also detected among the products of ozonolysis obtained under mild conditions of breakdown. 2. Products of oxidative breakdown of the ozonide of the rubber in question with hydrogen peroxide were acetic, formic, succinic, 1,2,4-butanetricarboxylic, 1,2,3-propanetricarboxylic and 1,x,y,6-hexanetetracarboxylic acids. Acetic acid could have been formed from 1,4-1,4-portions of the rubber molecule branched at the α -methylene group, as well as from isomerized 1,4-1,2-1,4-portions.

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