Dibasic Esters

AH the common monobasic (107) and dibasic esters (108) of tetrahydrofurfuryl alcohol have been prepared by conventional techniques the dibasic esters and some of the mono esters are effective as primary or secondary plasticizers for vinyl polymers. Tetrahydrofurfuryl acrylate [2399-48-6] and methacrjiate [2455-24-5] specialty monomers, have been produced by carbonylation (nickel carbonyl and acetylene) of the alcohol (109) as weU as by direct esterification (110—112) and ester interchange (111). 

Health and Safety. Both N-methylpyrrohdinone and dibasic esters have very low vapor pressure which limits worker exposure to vapors. Manufacturers recommend that the same safety precautions be taken as with other organic solvents. Ha2ardous location requirements must be considered if the formula is flammable. Ventilation that reduces vapors to manufacturer s recommended exposure levels should be used. 

Environmental Impact. The volume of waste remover from these products is remarkably increased when compared to methylene chloride, petroleum, and oxygenate removers, since both /V-methy1pyrro1idinone and dibasic esters have low vapor pressures. Recovery of the remover after use is difficult because the finish is tesolubili2ed by the remover. A representative dibasic ester formula appears below for a thickened water rinse finish remover. 

The water solubiUty of glutaric acid fosters its toxicity. Glutaric acid is a known nephrotoxin. Renal failure has been documented ia rabbits adruinistered sodium glutarate subcutaneously (124). Dibasic ester (Du Pont), which contains primarily dimethyl glutarate, has low acute toxicity by inhalation and by ingestion, and is moderately toxic via dermal absorption. The acid is both a dermal and ocular irritant of humans. The ester is a severe skin irritant and may cause a rash ia humans (120). 

Dibasic Esters, technical bulletin, Du Pont Chemicals, Wilmington, Del., 1991. 

MSDS 00000004, Dibasic Esters, Du Pont Chemicals, July 1991. 

Katrib, Y., Le Calve, S., Mirabel, P. Uptake measurements of dibasic esters by water droplets and determination of their Henry s law constants, / Phys. Chem. A, 107(51) 11433-11439, 2003. 

The use of dibasic esters in this general condensation has also been studied in considerable detail. Much of this information has been disclosed in the form of patents. Two or more moles of biguanide react with esters of aliphatic dibasic acids 700) to yield diguanamines as expected. Insufficient biguanide gives rise to mixtures, said to consist of the polymethylene diguanamines and an o>-carbalkoxy-polymethyleneguanamine. 

According to Thurston (702), the lower dibasic esters yield pure carbox5unonoguanamines so readily that this reaction is an excellent synthetic route, when confined to the lower esters. It has been apphed to 1-aryl- and alkyl-biguanides as usual, and to the alkali metal salts of half esters. The reaction involving diethyl malonate is represented below succinic acid esters (292, 699) react similarly. 

Direction of innovation tfrom the standpoint of the SubChem research group - 6bl Some of the available alternatives, particularly the dibasic esters, are of lower risk mainly due to their lower vapom pressure. In contrast high volatile DCM-substitutes like methanol, can not be regarded as a suitable alternative for enviromnental and health purposes. 

Aschmann, S. M and R. Atkinson, Rate Constants for the Gas-Phase Reactions of Selected Dibasic Esters with the OH Radical, Int. J. Chem. Kinet., 30, 47f-474 (f998b). 

Typical of the sort of data needed to determine whether additives affect the interface is that provided by a study of the influence of n-heptyl compounds on the gel structure of dispersions containing polar solids in nonpolar vehicles (70). The influence of the polar heptyl compounds on the fluidity of dispersions of rutile and a fine silica (HiSil) in a dibasic ester, Plexol 201, is shown in Fig. 7. Apparently, the more polar rutile adsorbs all except the chloride and in these cases thinning results. HiSil has a lower F value and adsorbs only the amine and alcohol preferentially. Greases prepared from the least polar solid, Aerosil, are also least influenced by these additives (or even by more complex ones). Measurements of the solution isotherms for HiSil and Aerosil reveal significant adsorption of heptyl alcohol, but no detectable chloride adsorption in the same concentration range. 

Other Organic Removers. Concerns over the reported toxicity and carcinogenicity of methylene chlonde have stimulated research for alternative solvents in remover formulas. N-Methylpyrrolidinone and dibasic esters (dimethyl glutarate or dimethyl adipate) have been used in removers. They remove single-component finishes but work much more slowly than methylene chloride, petroleum, and oxygenate group removers. They haw little success on epoxy and catalyzed finishes. 

Reaction XLVII. Condensation of an Ester with itself by the action of Iodine on its Sodio-derivative. (B., 23, R., 141 A., 201, 144 266, 88.) When iodine, usually in ethereal solution, acts on the sodio-derivatives of esters, such as malonic or acetoacetic esters, the metal is eliminated, and higher dibasic esters are obtained. As will be seen, the reaction is especially useful for preparing cyclo-paraffins by acting with iodine (or bromine) upon disodio-methylene- and disodio-ethylene-, etc., di-malonic esters. 

The monosodium derivative of aceto-acetic ester on treatment with iodine undergoes condensation to a dibasic ester (diaceto-succinic ester). 

By condensing formic ester with other monocar-boxylic esters, aldehyde esters result, while by using oxalic ester, ketonic dibasic esters are formed ... 

Many years ago, Brown and Walker3 found that by electrolysis of mono-esters of dibasic acids, carbon dioxide was removed, and the residues condensed to form a dibasic ester of higher molecular weight. 

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