Calcium carboxylates

Detergents are designed to be effective in hard water meaning water containing calcium salts that form insoluble calcium carboxylates with soaps These precipitates rob the soap of Its cleansing power and form an unpleasant scum The calcium salts of synthetic deter gents such as sodium lauryl sulfate however are soluble and retain their micelle forming ability even m hard water... 

Like most other metal carboxylates, the calcium carboxylate (Ca(RCOO)2) formed during Equation (6.19) readily forms a soap , the name arising since its aqueous solutions feel slippery and soapy to the touch. The other commonly encountered metal carboxylates are the major components of household soap, which is typically a mixture of potassium stearate and potassium palmitate (the salts of stearic and palmitic acids). 

Einspahr, H., and Bugg, C. E. (1981). The geometry of calcium-carboxylate interactions in crystalline complexes. Acta Crystallogr. Sect. B 37, 1044-1052. 

Ca Zn formulations are a complex blend of calcium and zinc soaps together with acid acceptors and organic co-stabilisers. Efforts have been made to increase the acid absorption capability in these systems (46,82,137, 295). The role of the co-stabiliser is also critical in maintaining initial colour and early colour hold on processing (47, 220, 308, 406, 407). Alternative calcium carboxylates have also been evaluated (227). 

International Polymer Science and Technology 28, No.l, 2001, p.T/69-73 NEW STABILISERS FOR POLYVINYL CHLORIDE - MIXED SALTS OF CALCIUM CARBOXYLATES... 

This work aims to produce mixed calcium carboxylate stabilisers for use in place of calcium stearate for the stabilisation of PVC. The new stabilisers are based on mixed salts of stearic acid with derivatives of phthalic or maleic acid and also with branched alpha, alpha-branched carboxylic (C12-C16) acids, noted for their lower cost and adequate effectiveness. Test results are examined in detail for the performance of these stabilisers in terms of service properties, processability, and stabilising action. 2 refs. (Translated from Plasticheskie Massy, No.5, 2000, p.19)... 

Further reactions occur, including processes catalyzed by the solid products, where the different organic anions give various carbonaceous radicals. The participation of acetate in malonate breakdown has already been discussed above. Decompositions of calcium carboxylates have been used as a method of ketone preparation in organic chemistry. 

The three commonly observed modes of calcium carboxylate ligation. (A) The unidentate mode, in which the calcium ion interacts with only one of the two carboxylate oxygens. (B) The bidentate mode, in which the calcium ion is chelated by both oxygen atoms. (C) The a-mode, in which the calcium ion is chelated by one carboxylate oxygen, and another ligand is attached to the a-carbon. Adapted from Reference 11. 

To follow the consumption of zinc and calcium carboxylates during heating time in the Brabender plasticorder at 190 °C, the following recipe was used PVC, 30 g dioctylphthalate, 9 g zinc or calcium stearate, 6.6 phr for the synergistic mixture zinc stearate, 3.3 phr and calcium stearate, 3.3 phr. These amounts of stabilizers are about three or four times larger than the quantity used in industrial conditions to facilitate the methods of titration. The plasticorder is stopped occasionally, and from all the samples only one part is placed in solution in tetrahydrofuran for titration of chlorides and stearic acid. 

Carboxylic acid esters from calcium carboxylates... 

Neutral and overbased calcium carboxylate liquids are similarly prepared. Because of the ratio of atomic weights, the concentrations (percent Ca) that can be reached are about one-third that of barium. A general supposition is that Ca/Zn liquids are not as effective as their Ba/Zn counterparts. This is no longer axiomatic. When combined with zeolite or hydrotalcite based booster, activity may be completely equivalent. In addition, the use of light metals minimizes plateout and, in clear compounds, haze. Added to this is the perception of a less hazardous formulation. Ca/Zn stabilizers have acute oral LD50 values in laboratory animals of greater than 5000mg/kg of... 

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