by a reaction of a few of the aldehyde groups with hydrazide hydrochloride. Both betaine hydrazide hydrochloride, a quaternary nitrogen-substituted hydrazide, and N,N-dimethylglycine hydrazide hydrochloride, a tertiary nitrogen-substituted hydrazide, are water soluble and react with carbonyl groups at relatively low temperatures and moderate acidity. These reaction conditions are favorable for adding a small amount of cationic material to DAS without degradation. As in the first route to cationic DAS, a complex family of products is available. In order to achieve high wet strength in paper* and improve dry strength, high retention on wood pulp fibers is required. DAS without cationic substituents had required a retention aid in the wet end of the papermaking machine. The new cationic DAS does not require such an aid, but dispersion conditions must be controlled to get good water solubility Without molecular degradation. This can be done by adjusting the percentage of cationic groups, temperature of the water, and heating time. Other Improvements. Two more developments may make cationic dialdehyde starch even more attractive. One is the development of an annular electrolytic cell for the oxidation of iodate semicol. The other is a method for rapid photometric determination of dialdehyde starch in paper. The annular cell, described by USDA's H. F. Conway and E. B. Lancaster at last week's 1962 spring meeting of the Electrochemical Society in Los Angeles, is an apparatus for continuously regenerating the expensive periodate used to oxidize starch to dialdehyde starch. An older, plate-type electrolytic process is now used for this purpose. Efficient regeneration of the periodate is the key to producing at relatively low costs. The other method, an analytical photometric method, would be important for determining the retention of either DAS or cationic DAS. A reflection densitometer measures color intensity of the p-nitro phenyl hydrazone of DAS, a derivative formed right in the paper. Miles Chemical, Elkhart, Ind., according to president Howard F. Roderick, is doing a lot of work in this field and is interested in derivatives of dialdehyde starch, but is not yet at a stage where it can discuss plans for the new material or estimate economics of using it.
Du Pont Cuts Price of Glutaric Anhydride Price is reduced by 20%; new plant converts dicarboxylic acids to their anhydrides, separates them by fractional distillation Following right after its announced plans to build a multimillion pound-ayear glutaric-succinic anhydride plant at Belle, W.Va. (C&EN, May 7, page 19), Du Pont is reducing the price of glutaric anhydride by 20%. The development price of 50 cents per lb. has been dropped to 40 cents per lb. in lots of 100 lb. or over and to 45 cents per lb. in 10-lb. lots, f.o.b. Belle. Although it is impossible to predict with certainty, Du Pont says that these new prices will also be the commercial prices when the new plant goes on stream in mid-1963. The reason for going to the commercial price now is to help develop a market in the highly competitive fields that glutaric anhydride is slated to enter— plasticizers, curing agents for epoxy resins, polyester resins, polyurethanes (polyester type), pharmaceutical intermediates, photochemicals, and textiletreating materials. And not only will the competition come from materials already well-entrenched in these areas, but also from some new ones. Harchem, for example, plans to build a new 10 to 20 million lb.-a-year plant for its two new dibasic acids—suberic and d o d e o anedioic—and has tentatively set the price of its compounds in the 40 centper-lb. range (C&EN, April 30, page 50). Du Pont's new plant will make glutaric anhydride as its main product, with succinic anhydride as a coproduct. The company is not revealing any details on the materials balance, but does describe the process in its patent (U.S. 2,971,010) on the production of dicarboxylic acid anhydrides from the catalytic air oxidation of cyclohexane. The broad patent is particularly directed to the preparation and separation of the individual dibasic carboxylic acid anhydrides from mixtures containing the corresponding acids and other reactants such as the monobasic carboxylic acids, nitric acid, and metallic salts. The process, says Du Pont, gives almost 100% conversion of the lower molecular weight dicarboxylic
acids to their anhydrides which are then separated by fractional distillation. Du Pont, which has been making glutaric anhydride in a semiworks plant at Belle since about October 1960, intends to sell the new plant's output mostly to outside users. But departments within the company are looking at the materials and some internal uses may develop. Better Properties. Du Pont's hopes for glutaric anhydride are pinned in large measure to the fact that it is an anhydride having an odd-number (five) of carbon atoms. And, further, glutaric anhydride is a fairly stable compound with a low melting point (56.5° C ) . Polymers that include glutaric anhydride have good low temperature properties, toughness (impact resistance), and flexibility. Also they veiy often have lower melting points than polymers composed of reactants having an even number of carbons. This low melt property is useful in resin casting or impregnating, and often means that the glutarate is a liquid, whereas a homologous compound made with the even-numbered dibasic acid is a solid. Thus, polyethylene glutarate is a liquid at room temperature and polyethylene adipate is a solid at room temperature. Another feature is that it is possible to isolate a half-ester in the reaction of glutaric anhydride with an alcohol. It is not possible to stop the reaction so neatly when any dibasic acid is used in place of glutaric. The half-esters can, in turn, be reacted with amines to form ester amides. Du Pont plans to sell glutaric anhydride for use in making plasticizers, but does not plan to make the plasticizers itself. The glutaric plasticizers are compatible with polyvinyl chloride and dioctyl phthalate and yield polymers having characteristics similar to those using di-2-ethylhexyl azelate and di-2-ethylhexyl sebacate. But, Du Pont says, there is a manufacturing materials cost advantage when the glutarate is used as the plasticizer rather than these materials. MAY 14F 1962 C&EN
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