Process for reducing the levels of fatty acid contaminants in polyhydroxy fatty acid amide surfactants
First Claim
1. In a process for preparing a primary reaction product comprising a polyhydroxy fatty acid amide surfactant, said reaction product containing undesirable amounts of free fatty acids or nascent source of fatty acids, said process comprising a primary reaction between a sugar-derived or glyceraldehyde-derived polyhydroxy amine and a fatty acid ester, said primary reaction being carried out at a temperature below about 100°
- C. so as to minimize formation of cyclized by-products in said reaction product, the improvement which comprises running the primary reaction under substantially water-free conditions, whereby the formation of free fatty acids and soaps is minimized, and adding to said primary reaction product an amine reaction which is a member selected from the group consisting of ammonia, short-chain alkyl amines and short-chain hydroxyalkyl amines and subjecting said reaction product to a secondary reaction, whereby the total level of residual nascent and free fatty acid present in said primary reaction product is reduced to below about 1%, by weight.
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Abstract
The synthesis of polyhydroxy fatty acid amide surfactants exemplified by the compound C11 H23 C(O)N(CH3)CH2 [CHOH]4 CH2 OH by reacting a fatty acid ester with an N-alkyl sugar amine can result in contamination of the product surfactant by residual sources of fatty acids. These residual fatty acids may be unacceptable in high sudsing detergent compositions, such as dishwashing liquids, especially with Ca or Mg cations. The process of this invention reacts such contaminants with alkyl amines or, especially, ethanolamine, to convert them into fatty alkyl- or alkanolamides, which are quite acceptable in fully-formulated detergent compositions for home or industrial use.
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Citations
12 Claims
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1. In a process for preparing a primary reaction product comprising a polyhydroxy fatty acid amide surfactant, said reaction product containing undesirable amounts of free fatty acids or nascent source of fatty acids, said process comprising a primary reaction between a sugar-derived or glyceraldehyde-derived polyhydroxy amine and a fatty acid ester, said primary reaction being carried out at a temperature below about 100°
- C. so as to minimize formation of cyclized by-products in said reaction product, the improvement which comprises running the primary reaction under substantially water-free conditions, whereby the formation of free fatty acids and soaps is minimized, and adding to said primary reaction product an amine reaction which is a member selected from the group consisting of ammonia, short-chain alkyl amines and short-chain hydroxyalkyl amines and subjecting said reaction product to a secondary reaction, whereby the total level of residual nascent and free fatty acid present in said primary reaction product is reduced to below about 1%, by weight.
- View Dependent Claims (2, 3, 4, 5, 6, 9, 10, 11, 12)
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7. An improved process for preparing polyhydroxy fatty acid amide surfactants comprising:
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(a) a primary amidation reaction conducted under substantially water-free conditions between a fatty acid ester and a sugar-derived or glyceraldehyde-derived polyhydroxyamine to prepare a polyhydroxy fatty acid amide surfactant which is contaminated with residual nascent fatty acids, followed by; (b) a secondary reaction which comprises admixing and reacting with the reaction product of primary reaction (a) an amine reactant which is a member selected from the group consisting of ammonia, short-chain alkyl amines and short-chain hydroxy alkly amines, whereby the level of residual nascent fatty acids and free fatty acids is lowered to below about 0.5% by weight in the final surfactant. - View Dependent Claims (8)
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Specification