Ammonium lignin sulfonate

Selection of Lignin Substrate. The lignin sulfonate chosen for the initial experiments was an ammonium salt rather than the corresponding calcium, magnesium, or sodium counterparts, which are the other commercial forms available. This selection was made on the basis that ammonium lignin sulfonates actually differ significantly in physical and chemical properties from the... 

The nature of the covalently bound nitrogen in ammonium lignin sulfonates or the associated carbohydrates has not yet been reported, but if it is present as a primary or secondary amine, the reactivity toward formaldehyde would likely be increased (5) and the crosslink density of the resultant adhesive thereby augmented. 

Choice of the Lignin Modification Reaction. The phenolysis reaction was selected as a means of modifying the structure and reactivity of the ammonium lignin sulfonate for three main practical reasons. First, because this lignin derivative is soluble in (and will ultimately be used in conjunction with) liquid phenol itself second, because unreacted phenol, unlike other reaction solvents, would not have to be removed from the phenolated product after reaction and before conversion to the adhesive resin and third, because lignins and carbohydrates are known to react with phenols under acidic conditions (6,7). 

Phenolysis Reaction Procedure. To explore the concept of phenolation, mixtures of a commercial spray-dried softwood ammonium lignin sulfonate (10 g, Orzan A, 60% ammonium lignin sulfonate (MW0 = 228), 28% sugars, 6.2% sulfur, 2.5% ash, ITT-Rayonier, Shelton, Washington available in bulk at 17 cents a pound (<9) and commercial grade phenol (15 mL, Reichhold Chemicals Inc., Tacoma, Washington) contained in small pressure bombs (30 mL, Parr Instrument Company, Moline, Illinois) were heated by suspension in a hydraulic... 

Table I. Effect of Duration of Heating on the Ammonium Ion Content of a Mixture of Ammonium Lignin Sulfonate and Phenol (61.5%)...

Table II. Comparison of Total Pressure Generated by Heated Phenol and a Phenol-Ammonium Lignin Sulfonate (38.5%) Mixture in a Stirred Batch Reactor...

Another related set of experiments was also carried out to determine the effect of temperature on the insolubilization of the ammonium lignin sulfonate by phenolysis for a period of 2 hours. The results obtained, which are summarized in Table IV, show that more than one-third of the commercial product can be made water-insoluble by this procedure. 

Table IV. Effect of Reaction Temperature on Extent of Phenolysis and Degree of Water Insolubility Conferred upon a Commercial Ammonium Lignin Sulfonate Admixed with Phenol (61.5%) and Heated for 2 Hours...

Expressed in terms of the ammonium lignin sulfonate feed. 

Kinetic Study of the Phenolysis Reaction. With the demonstration that all of the already outlined deficiencies of ammonium lignin sulfonates as a phenol replacement can be reduced by phenolysis, attention was turned to consideration of the construction of a pilot plant scale continuous tube reactor. This is needed in order to prepare the large amounts of phenolyzed lignin sulfonates required for resin synthesis and testing under plywood production conditions. 

As a prelude to the design of the tube reactor (10), a kinetic study of the phenolysis procedure as a function of temperature was carried out on a larger scale. The equipment used was a stainless steel pressure reactor (Model 4501, Parr Instrument Company, Moline, Illinois). This reactor is fitted with an internal stirrer, an external electric heater, and a continuous sampling device. A mixture of the commercial ammonium lignin sulfonate (668 g) and molten phenol (1000 mL) was sealed into the reactor and heated to the designated temperatures. Approximately 3 hours were needed to heat the reactor from room temperature to 200 °C. A similar period of time was required to cool the reactor and its contents back to 22 °C after completion of a run. After a reaction period nominally lasting 2 hours, the unreacted phenol was steam distilled from the reaction mixture and the amount measured by comparative UV spectroscopy. The results obtained and summarized in Table IV show that a substantial amount of phenol becomes chemically combined with the renewable resource feedstock. 

Ammonium lignin sulfonate. See Ammonium lignosulfonate Ammonium lignosulfonate CAS 8061-53-8... 

Synonyms Ammonium lignin sulfonate Lignosulfonic acid, ammonium salt... 

Solubility of Phenolated Lignin Sulfonates. Since the presence of ammonium sulfonate moieties tends to confer water solubility, their disappearance should be reflected in a reduction of this characteristic. The extent of this effect was assessed by measuring the solubility of a stirred aliquot (1-4 g) of the 200 °C phenolysis product in water (200 mL). The resultant suspension was filtered and the residue dried for about 2 days at 22 °C to constant weight. The results obtained under a variety of reaction conditions are summarized in Table III. 

Ammonium lignosulfonate Lauramine Lignin sulfonate Myristamine Nonoxynol-13 Soyamine... 

Lignin sulfonates are, technically, low-molecular-weight polymers containing a witch s brew of primary and secondary alcohols, phenols, and carboxylic acid functionalities. They are prepared by the sulfonation of lignin byproducts of pulp and paper manufacture, followed by neutralization to the sodium, calcium, or ammonium salt. The resulting materials are useful as dispersing agents for solids and oil/water emulsions, and as stabilizers for aqueous dispersions of dyes, pesticides, and cement. They are very inexpensive relative to other materials and are very... 

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