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Should I dilute sulfonic acid before neutralizing it with Sodium hydroxide ?
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12% LABSA, 6% active SLES works fine (intended as a liquid laundry detergent)
it doesn’t cloud in the fridge at all, but you must add both some CAPB and NaCl ( <0.25% ) to thicken it.I tried the same formula neutralizing it with KOH instead of NaOH and it became real cloudy. Cloudy even before all the LABSA was neutralized.
That was unexpected, as Potassium salts usually have better solubility than their Sodium counterparts.Some 2.5% dipropylene glycol made it clear again, but it sharply reduces viscosity.
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@Gunther
https://ejchem.journals.ekb.eg/article_7631_aed50d75c833b783095ca669b368d51a.pdfI reviewed the above link you provided. Have you tried testing that formulation? Right now I have the below formula. Is it any good?
SLES 5.00% LABS 6.50% CDEA 1.00% DMDM 0.05% Colorant 0.01% Scent 0.10% Caustic 1.70% Water Balance I’m thinking of adding AOS powder to the formulation you provided because there are studies that 80:20 ratio of LABSA and AOS results to high foaming. What do you think?
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Among the common anionic surfactants, LABS is the most hydrophobic (due to the aromatic ring). Addition of electrolytes (like NaCl) makes it even more hydrophobic and prone to precipitation, since Na+ ions neutralize the negative charge of SO3-, which is the water soluble part of the molecule; that’s why the more NaCl is added, the lower the cloud point.
One thing to work around this problem (without using an hydrotrope which impair foam and performance) is to neutralize it with TEA, since TEA-alkylbenzene sulfonate is more soluble than its sodium counterpart. You can use only TEA (more expensive), or a mixture of TEA and NaOH. Another way is to change the ratio LABS/LESS (a good starting point is 8:2, and to improve solubility, you can increase LESS and reduce LABS).
Also, keep in mind that some surfactants have hidden amounts of NaCl, like Betaines and Amine oxides. Interestingly, Lauramidopropylamine oxide allows lower cloud points than the other amine oxides, while producing more foam and even helps build more viscosity. Besides amine oxides, olefin sulfonates and sultaines also help achieve more foam at low doses. There are also some polymers which are very useful, such as Sokalan HP20 and Supracare 801.
pH also plays a major part, since pH lower than 5 make Betaines and Amine oxides behave as cationics, clouding the product right away; for better clarity, a pH above 8 is advised.
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ketchito said:Among the common anionic surfactants, LABS is the most hydrophobic (due to the aromatic ring). Addition of electrolytes (like NaCl) makes it even more hydrophobic and prone to precipitation, since Na+ ions neutralize the negative charge of SO3-, which is the water soluble part of the molecule; that’s why the more NaCl is added, the lower the cloud point.
One thing to work around this problem (without using an hydrotrope which impair foam and performance) is to neutralize it with TEA, since TEA-alkylbenzene sulfonate is more soluble than its sodium counterpart. You can use only TEA (more expensive), or a mixture of TEA and NaOH. Another way is to change the ratio LABS/LESS (a good starting point is 8:2, and to improve solubility, you can increase LESS and reduce LABS).
Also, keep in mind that some surfactants have hidden amounts of NaCl, like Betaines and Amine oxides. Interestingly, Lauramidopropylamine oxide allows lower cloud points than the other amine oxides, while producing more foam and even helps build more viscosity. Besides amine oxides, olefin sulfonates and sultaines also help achieve more foam at low doses. There are also some polymers which are very useful, such as Sokalan HP20 and Supracare 801.
pH also plays a major part, since pH lower than 5 make Betaines and Amine oxides behave as cationics, clouding the product right away; for better clarity, a pH above 8 is advised.
Very very interesting.
Thank you for posting that.Do you have some references or interesting reads on that?
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@ketchito
What is LESS? Was that a typo? Are you referring to SLES? Thanks for the info. -
ketchito said:Among the common anionic surfactants, LABS is the most hydrophobic (due to the aromatic ring). Addition of electrolytes (like NaCl) makes it even more hydrophobic and prone to precipitation, since Na+ ions neutralize the negative charge of SO3-, which is the water soluble part of the molecule; that’s why the more NaCl is added, the lower the cloud point.
One thing to work around this problem (without using an hydrotrope which impair foam and performance) is to neutralize it with TEA, since TEA-alkylbenzene sulfonate is more soluble than its sodium counterpart. You can use only TEA (more expensive), or a mixture of TEA and NaOH. Another way is to change the ratio LABS/LESS (a good starting point is 8:2, and to improve solubility, you can increase LESS and reduce LABS).
Also, keep in mind that some surfactants have hidden amounts of NaCl, like Betaines and Amine oxides. Interestingly, Lauramidopropylamine oxide allows lower cloud points than the other amine oxides, while producing more foam and even helps build more viscosity. Besides amine oxides, olefin sulfonates and sultaines also help achieve more foam at low doses. There are also some polymers which are very useful, such as Sokalan HP20 and Supracare 801.
pH also plays a major part, since pH lower than 5 make Betaines and Amine oxides behave as cationics, clouding the product right away; for better clarity, a pH above 8 is advised.
You’re right!
I just tried 15 and 20% LABSA neutralized with TEA and they was clear (if neutralized with Sodium hydroxide they would have been cloudy)They were clear even with 0.5% salt, albeit -TEA viscosities were lower than those for -Sodium.
While I still need to conduct a salt curve and cost analysis, but this quick experiment shows you were totally right. -
Gunther said:ketchito said:Among the common anionic surfactants, LABS is the most hydrophobic (due to the aromatic ring). Addition of electrolytes (like NaCl) makes it even more hydrophobic and prone to precipitation, since Na+ ions neutralize the negative charge of SO3-, which is the water soluble part of the molecule; that’s why the more NaCl is added, the lower the cloud point.
One thing to work around this problem (without using an hydrotrope which impair foam and performance) is to neutralize it with TEA, since TEA-alkylbenzene sulfonate is more soluble than its sodium counterpart. You can use only TEA (more expensive), or a mixture of TEA and NaOH. Another way is to change the ratio LABS/LESS (a good starting point is 8:2, and to improve solubility, you can increase LESS and reduce LABS).
Also, keep in mind that some surfactants have hidden amounts of NaCl, like Betaines and Amine oxides. Interestingly, Lauramidopropylamine oxide allows lower cloud points than the other amine oxides, while producing more foam and even helps build more viscosity. Besides amine oxides, olefin sulfonates and sultaines also help achieve more foam at low doses. There are also some polymers which are very useful, such as Sokalan HP20 and Supracare 801.
pH also plays a major part, since pH lower than 5 make Betaines and Amine oxides behave as cationics, clouding the product right away; for better clarity, a pH above 8 is advised.
Very very interesting.
Thank you for posting that.Do you have some references or interesting reads on that?
My pleasure. There are some great books where you can find very nice info, like: “Anionic surfactants: organic chemistry”, “Liquid detergents” and “Handbook of detergents”, all from CRC Press.
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I’m glad it helped!
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Hope Gunther sir could arrive at a solution to his problem…
Here is the recipe for dishwashing liquid that works like a magic…
Thanks to Engr. EMIL J. RICAFORTE sir…
https://pichenet.org/attachments/Technical_Demo_A__Ricaforte.pdf
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@Gunther can you please explain the final process by which your issue was resolved?
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