Alkali sodium tripolyphosphate

Tetrasodium pyrophosphate, Na4P207, is another important primary builder and detergent. In sequestration, it is not as effective as sodium tripolyphosphate and its usage in heavy-duty laundry powders has declined in recent years. Functionally, tetrasodium pyrophosphate is both a builder for surfactants (i.e., water softener) and alkali. 

Alkaline flooding is also called caustic flooding. Alkalis used for in situ formation of surfactants include sodium hydroxide, sodium carbonate, sodium orthosilicate, sodium tripolyphosphate, sodium metaborate, ammonium hydroxide, and ammonium carbonate. In the past, the first two were used most often. However, owing to the emulsion and scaling problems observed in Chinese field applications, the tendency now is not to use sodium hydroxide. The dissociation of an alkali results in high pH. For example, NaOH dissociates to yield OH" ... 

Chang (1976) showed that use of a polyphosphate, which is a buffer, improved recovery. Sodium tripolyphosphate (STPP) was used in laboratory tests for Cretaceous Upper Edwards reservoir (Central Texas). STPP was proposed to minimize divalent precipitation, for wettability alteration and emulsification (Olsen et al., 1990). Generally, it is not used as a primary alkali to generate soap for purposes of IFT reduction. Instead, it is used together with other alkalis such as sodium carbonate when divalents could be a problem (Harry Chang, Chemor Tech International, Plano, Texas, personal communication on June 16, 2009). 

Alkali Formula Sodium Hydroxide NaOH Sodium Carbonate Na2C03 Sodium Orthosilicate Na4Si04 Sodium Tripolyphosphate NasP 30-10 Ammonium Hydroxide NH4OH ... 

Water 73.0 Sodium Tripolyphosphate 5.0 50% NaOH 10.0 42 Sodium Silicate 3.22/1 8.0 Tomah Alkali Surfactant 2.0 Nonionic Surfactant 2.0... 

Water 95.0 Sodium Tripolyphosphate 1.0 50% NaOH 2.0 Tomah Alkali Surfactant 1.0 Nonionic Surfactant 1.0... 

Most anionic surfactants are salts of moderately strong acids. As such, they can be titrated directly with base, provided that a suitable solvent system and visual or instrumental end point can be found. However, since anionic surfactants are generally found in the company of other ionic materials, some of them also acidic, direct acid-base titration is not used for most applications. For example, acid-base titration for assay of alkylarylsulfonate would risk high results because of titration of byproduct sulfate or other ions. Acid-base titration of LAS in a detergent formulation suffers from interference from such buffering compounds as sodium silicate and sodium tripolyphosphate. Titration with alkali is therefore limited to cases where the anionic surfactant can be isolated in pure form. 

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