Lignin. III. Fractional Precipitation of Barium Lignin Sulfonates from Water by Ethanol

Markham, Aaron E.; Peniston, Quintin P.; McCarthy, Joseph L.

doi:10.1021/ja01179a006

Cited by 15 publications

(5 citation statements)

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“…Laboratory methods for isolating lignosulfonates include dialysis (71,72), electrodialysis (73), ion exclusion (73,74), precipitation in alcohol (75,76), and extraction with amines (77)(78)(79). They can also be isolated by precipitation with long-chain substituted quarternary ammonium salts (80)(81)(82).…”

Section: Isolation Of Lignosulfonates Various Methods Have Been Devementioning

confidence: 99%

Lignin

Lebo¹,

Gargulak²,

McNally³

2001

Kirk-Othmer Encyclopedia of Chemical Technology

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On treatment with oxidants such as chlorine, hypochlorite anion, chlorine dioxide, oxygen, hydrogen peroxide, and peroxy acids, the aromatic nuclei in lignin typically are converted to o-and p-quinoid structures and oxirane derivatives of quinols. Because of their relatively high reactivity, these structures often appear as transient intermediates rather than as end 2 LIGNIN Vol. 15Reactions that involve the formation and elimination of multiple bond functional groups may significantly effect the color of residual lignin in bleached and unbleached pulps. The ethylenic and carbonyl groups conjugated with phenolic Vol. 15

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Section: Isolation Of Lignosulfonates Various Methods Have Been Devementioning

confidence: 99%

Lignin

Lebo¹,

Gargulak²,

McNally³

2001

Kirk-Othmer Encyclopedia of Chemical Technology

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“…I t has been found that the methoxyl content of the fractions increases with decreasing diffusion coefficient (23), i.e. with increasing molecular weight, while the sulphur content of the fractions, with few exceptions (18), decreases with increasing methoxyl content.…”

Section: Introductionmentioning

confidence: 97%

“…Various methods of separating ligninsulphonates from the other constituents have been used (2,14) including precipitation, dialysis, and ion exchange. Attempts have also been made t o fractionate the highly polydisperse ligninsulphonates according t o their molecular weights by fractional dialysis (6,32), fractional extraction of the free acids by propanol (31), fractional precipitation of the barium salts by ethanol (23) or acetone (25), countercurrent butanol extraction of free acids and amine salts in water (22), differential sorption on swollen ion-exchange resins (18), and fractionation by the different solubilities of various amine salts (4,5,19,25).…”

Section: Introductionmentioning

confidence: 99%

Physicochemical Studies of Ligninsulphonates: I. Preparation and Properties of Fractionated Samples

Gardon¹,

Mason²

1955

Can. J. Chem.

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High molecular weight lignins~~lphonates were separated from other constituents of spent sulphite liquor by a method of dialysis allolving c o n t i n~~o u s removal of the dialyzates and their replacement by distilled water. The process was controlled by continuous analysis of the residue and dialyzate. The lower molecular weight ligninsulphonates in the dialyzates were separated from the carbohvdrates bv precipitating their barium salts with ethanol: four fractions correspbnding to differkt times of dialysis were prepared in this manner. The ligninsulphonates in the dialyzed liquor mere separated into four additional fractions by ultrafiltration through membranes of different pore sizes. The methoxyl, sulphur, and phenolic hydrosyl contents, neutralizatior~ equivalent weights, reducing powers, ultraviolet absorption spectra, diffusion coefficients, and number-average molecular weights of the eight fractions were determined.The molecular weights of the fractions range from 3700 to 58,000 but the integral molecular weight distribution curve indicates the presence of ligninsulphonates with molecular weights as high as 100,000.

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“…Laboratory methods for isolating lignosulfonates include dialysis (82,83), electrodialysis (84), ion exclusion (84,85), precipitation in alcohol (86,87), and extraction with amines (88)(89)(90). They can also be isolated by precipitation with long-chain-substituted quaternary ammonium salts (91)(92)(93).…”

Section: Isolation Of Lignosulfonates Various Methods Have Been Devementioning

confidence: 99%

Lignin

Gargulak¹,

Lebo²,

McNally³

2015

Kirk-Othmer Encyclopedia of Chemical Technology

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The word lignin is derived from the Latin word lignum meaning wood. It is one of the main components of all vascular plants and the second most abundant polymer in nature. This article describes the current understanding of the structure of this complex natural polymer. The number and types of different chemical bonds present in lignin are discussed, as are the ways in which different lignins are identified and their distributions determined in plant tissues. Means for isolating lignin from wood are described, and the chemical and physical properties of the resulting lignins are reviewed. The various chemical and instrumental methods for characterizing isolated lignins are also discussed. The article concludes with a review of commercial lignin products including a discussion of producers, production methods, modification reactions, and the many industries in which lignins are used.

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Lignin. III. Fractional Precipitation of Barium Lignin Sulfonates from Water by Ethanol

Cited by 15 publications

References 1 publication

Lignin

Lignin

Physicochemical Studies of Ligninsulphonates: I. Preparation and Properties of Fractionated Samples

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