Sebacates and adipates

These materials provide good low-temperature plasticizers for PVC, in liquid form, with fairly general food-contact approval. Dibutyl sebacate is a highly efficient primary plasticizer for low-temperature applications, and is used in films and containers for packaging. 

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Burns [65] has carried out an extensive study of the TLC of phthalate, sebacate and adipate ester systems and also chlorinated waxes such as Cleroxide, Cereclor S, Pliabrac and hexylene glycol, nsed in PVC formulations. He employed 1 mm thick layers of Silica Gel G activated for 3 honrs at 110-115 °C for achieving separations. Burns [65] found that benzene - ethyl acetate (100 1) was much more efficient than the benzene - ethyl acetate (20 1) mixtures. He also used freshly redistilled dichloromethane (DCM), iso-octane -ethyl acetate acid (4 4 1), and benzene - DCM (4 1) as migration solvents. 

Figure 3 shows the results of CALB-catalyzed polymerizations as a function of diacid chain length in solvent. The more rapid polymerization in diphenyl ether of sebacic (Cio) acid relative to shorter diacid substrates was evident by 4 and 8 h. However, by 24 and 48 h, the DPavg for sebacic and adipic diacid (Q) polymerizations was statistically equivalent. Similarly, polymerizations of succinic (C4) and glutaric (C5) diacids proceeded at similar rates. Thus, by 24 h, the relative extent of chain-build up for polymerizations with octane-1,8-diol in diphenyl ether was sebacic adipic > glutaric succinic acids. It may be that the kinetics of sebacic acid /1,8-octanediol polymerization is more rapid than for the other diacids studied. 

Among the additives used to modify the properties of polymeric packaging materials, plasticisers have raised much concern from the hygienic point of view. Butyl stearate, acetyltributyl citrate, alkyl sebacates and adipates are important because they are types of plasticisers that typically have low toxicities. Materials such as epoxidised soybean oil are widely used in polyvinyl chloride, polyvinylidene chloride and polystyrene as thermal stabilisers and lubricants at a level of 0.1-27%. Toxicity of epoxidised soybean oil is affected by the presence of oxirane, also known as ethylene oxide, which was upgraded to Group 1 as a carcinogenic agent to humans, based on mechanistic and other relevant data. 

Phthalates exhibit the greatest resistance, white sebacates and adipates exhibit iess resistance. Addition of phosphates to DOP does not resuit in an increase in fungus resistance, see Tabie 5.i35 [972],... 

Other ester plasticizers such as sebacates and adipates as well as low molecular weight polyester plasticizers can sometimes substitute for the phthalate plasticizers. However, these alternatives might cost more. Also, in some cases, even vegetable oil derivatives have been considered and evaluated as alternatives. 

A primary plasticiser for PVC is regarded as one which is fully compatible with the resin up to at least 100 parts per hundred parts resin (phr) and can be satisfactorily used for many applications as the sole plasticiser. Phthalate and phosphate esters and certain polyesters come into this category. A secondary plasticiser has limited compatibility with PVC, but is normally incorporated in a PVC compound as a partial replacement for a primary plasticiser to impart a specific desirable physical property. Low temperature plasticisers such as sebacates and adipates are typical of this category. Plasticiser extenders are plasticisers of limited efficiency and compatibility such as chlorinated paraffins and certain hydrocarbon oils, which are included in the composition to reduce costs. 

Low Temperature Performance. The abihty of plasticized PVC to remain flexible at low temperatures is of great importance in certain apphcations, eg, external tarpaulins or underground cables. Eor this property the choice of the acid constituent of the plasticizer ester is also important. The linear aUphatic adipic, sebacic, and azeleic acids give excellent low temperature flexibiUty compared to the corresponding phthalates and trimeUitates (Pig. 3). 

PVB resins are also compatible with a limited number of plasticizers and resins. Plasticizers (qv) improve processibility, lower T, and increase flexibihty and resiUency over a broad temperature range. Usehil plasticizers include dibutyl and butyl benzyl phthalates, tricresyl and 2-ethylhexyl diphenyl phosphates, butyl ricinoleate, dibutyl sebacate, dihexyl adipate, triethylene glycol di-2-ethylbutyrate, tetraethylene glycol diheptanoate, castor oil, and others (64-73). 

Diesters. Many of the diester derivatives are commercially important. The diesters are important plasticizers, polymer intermediates, and synthetic lubricants. The diesters of azelaic and sebacic acids are useflil as monomeric plasticizing agents these perform weU at low temperatures and are less water-soluble and less volatile than are diesters of adipic acid. Azelate diesters, eg, di- -hexyl, di(2-ethylhexyl), and dibutyl, are useflil plasticizing agents for poly(vinyl chloride), synthetic mbbers, nitroceUulose, and other derivatized ceUuloses (104). The di-hexyl azelates and dibutyl sebacate are sanctioned by the U.S. Food and Dmg Administration for use in poly(vinyl chloride) films and in other plastics with direct contact to food. The di(2-ethylhexyl) and dibenzyl sebacates are also valuable plasticizers. Monomeric plasticizers have also been prepared from other diacids, notably dodecanedioic, brassyflc, and 8-eth5lhexadecanedioic (88), but these have not enjoyed the commercialization of the sebacic and azelaic diesters. 

Room-temperature ionic liquids have received much attention as green designer solvents. We first demonstrated that ionic liquids acted as good medium for lipase-catalyzed production of polyesters. The polycondensation of diethyl adipate and 1,4-butanediol using lipase CA as catalyst efficiently proceeded in l-butyl-3-methylimidazolinium tetrafluoroborate or hexafluorophosphate under reduced pressure. The polymerization of diethyl sebacate and 1,4-butanediol in l-butyl-3-methylimidazolinium hexafluorophosphate took place even at room temperature in the presence of lipase BC. ... 

Polyamides, commonly known as nylons, may safely be used to produce articles intended for application in processing, handling, and packaging of food, including for products intended to be cooked directly in their packages. Nylon resins are manufactured by condensation of hexyamethylenediamine and adipic acid (nylon 66) or sebacic acid (nylon 610), by the polymerization process, e.g., of co-laurolactam (nylon 12), or by condensation and polymerization, e.g., nylon 66 salts and s-caprolactam. 

There are several plasticizers for PVC that may be used in propellants. Weil (19) mentions sebacates, phthalates, adipates, and glycol esters of higher fatty acids as being desirable. Dibutyl sebacate, dioctyl sebacate, and 2-ethylhexyl adipate are all good. The plasticizer has a most important effect on the physical properties of the cured propellant and the variation of these properties with temperature. Long chain, aliphatic plasticizers impart improved low temperature flexibility, and hence are preferable to aromatic plasticizers such as the phthalates. An increase in plasticizer viscosity leads to an increase in viscosity of the mixed pro-... 

Greases made with lithium stearate and synthetic oils, such as 2-ethylhexyl sebacate or adipate, are especially applicable to lubrication of bearings that are subjected to both high and low temperatures. An important application is lubrication of antifriction bearings and instruments in aircraft which may encounter temperatures as low as —100° F. at high altitudes. 

Myristic acid (from decanoic acid and methyl hydrogen adipate). Dissolve 55-2 g. of pure decanoic acid (capric acid decoic acid), m.p. 31-32°, and 25 -6 g. of methyl hydrogen adipate in 200 ml. of absolute methanol to which 0-25 g. of sodium has been added. Electrolyse at 2-0 amps, at 25-35° until the pH of the electrolyte is 8-2 (ca. 9 hours). Neutralise the contents of the electrolytic cell with acetic acid, distil off the methanol on a water bath, dissolve the residue in about 200 ml. of ether, wash with three 50 ml. portions of saturated sodium bicarbonate solution, and remove the ether on a water bath. Treat the residue with a solution of 8 0 g. of sodium hydroxide in 200 ml. of 80 per cent, methanol, reflux for 2 hours, and distil off the methanol on a water bath. Add about 600 ml. of water to the residue to dissolve the mixture of sodium salts extract the hydrocarbon with four 50 ml. portions of ether, and dry the combined ethereal extracts with anhydrous magnesium sulphate. After removal of the ether, 23-1 g. of almost pure n-octadecane, m.p. 23-24°, remains. Acidify the aqueous solution with concentrated hydrochloric acid (ca. 25 ml.), cool to 0°, filter off the mixture of acids, wash well with cold water and dry in a vacuum desiccator. The yield of the mixture of sebacic and myristic acids, m.p. 52-67°, is 26 g. Separate the mixture by extraction with six 50 ml. portions of almost boiling light petroleum, b.p. 40-60°. The residue (5 2 g.), m.p. 132°, is sebacic acid. Evaporation of the solvent gives 20 g. of myristic acid, m.p. 52-53° the m.p. is raised slightly upon recrystallisation from methanol. 

Inorganic compounds (includes organometallic compounds) Hydrocarbons C,-C5 (aliphatic) n-Decane di-n-decyl phthalate dimethyl sulfolane neopentyl glycol succinate 1,2,3-tris (2-cyanoethoxy) propane SE-30 (methyl silicone phases) Carbowax 400-1500 most branched and substituted phthalate, sebacate, succinate, and adipate phases octadecane squalane (boiling point separations) methyl silicones... 

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