Sequence of operation

Greetings to all the members of this prestigious forum.

My query is concerned with the sequence for addition of components of a product. For my case the product is a dishwashing liquid. The following is my formulation for a batch of 1000 kg of the finished product.

1. SLES 70% 2 moles EO - 70 kg
2. CAPB 30% - 10 kg
3. LABSA 96% - 40 kg
4. Citric Acid Anhydrous - 5 kg
5. Sodium Chloride - 15 kg
6. Sodium Hydroxide flakes - 11 kg
7. Lemon Fragrance - 2 kg
8. Yellow dye (food grade) - q.s 
9. Demin. Water - to 100 %

There are three parameters which I am trying to achieve. 
1. pH - 9-9.5
2. Viscosity - 1000 cps
3. Color - light yellow

The pH profile very much depends on the amount of components added and the sequence of addition. The same applies to viscosity profile. The color too depends on the sequence. While adjusting the pH I added sodium hydroxide at the last after everything was added and the color of the product instantly changed from light yellow to golden.

What is the correct sequence for addition of components in order to achieve the aforementioned parameters ?

Your valuable comments are awaited. 

Comments

  • PerryPerry Administrator, Professional Chemist
    I think the order would be...

    1.  Water
    2.  Dye
    3.  Citric acid
    4.  SLES
    5.  CAPB
    6.  LABSA
    7.  Fragrance
    8.  NaOH
    9.  Sodium chloride

    But this is just a guess. This is essentially the order of addition that we did when making shampoo.
  • ozgirlozgirl Member, PCF student
    I don't think that there is necessarily a "correct" order you just need to do it the same every batch. We generally neutralise the DDBSA as the first step when making our detergents so my recommended order would be

    Demin. Water - to 100 %
    Sodium Hydroxide flakes - 11 kg
    LABSA 96% - 40 kg

    SLES 70% 2 moles EO - 70 kg
    Lemon Fragrance - 2 kg
    Yellow dye (food grade) - q.s

    CAPB 30% - 10 kg
    Citric Acid Anhydrous - 5 kg
    Sodium Chloride - 15 kg


    I would also probably reduce the NaOH so that you don't need to use as much of the citric acid unless you actually want to create sodium citrate in your product.

    Hope this helps :)
  • Is it not true that sodium citrate helps in cutting oil and grease from dirty dishes ?

    I think that my formulation is an economical one. I am thinking of replacing CAPB by lauramine oxide and using ethoxylated nonyl phenols for enhancing the detergency. What do you think about the performance ? Will it improve or still be the same after incorporating NPE and LA ?
  • PerryPerry Administrator, Professional Chemist
    @ozgirl - we added the dye first because it is easy to make a mistake in measuring powdered color. After adding the dye we did a color check against a standard. If the color didn't match we could discard the water and start again. That's a lot more costly to do once the detergents have been added.

  • chemicalmattchemicalmatt Member, Professional Chemist
    Perry & Ozgirl are correct on the order sequence. Dyes generally are nonreactive so put first in case of an error, you only lost water as Perry says. Likewise ALWAYS add the NaOH into he water first, then slowly add LABSA to saponify in situ. Then add the rest, though I suggest adding a hydrotrope next (CAPB here). Sodium citrate is a "natural" but somewhat lame chelating agent, placed to retard redepostion of soils. Use tetrasodium EDTA for better results. Cheaper too. To answer your revision question: heck yes, NPE/Laura-O is a better detergent system than CAPB by a long shot. You have to watch out for NPE limits in California though. I hate it when they take our chemical toys away from us.
  • If I am to add NPE and replace CAPB by LA, What would be a good composition to begin with in order to have a product with enhanced performance ?
  • ozgirlozgirl Member, PCF student
    @Perry That is a good way to look at it. You are correct it is much cheaper to just discard coloured water if something goes wrong. Thankfully over the many years we haven't had any issues doing it our way.
  • We "dry" mix LABSA with SLES to form a paste (in a water bath as it warms itself up)
    then add some water, allow to hydrate/dissolve
    Then slowly pour NaOH solution
    Then color and fragrance.
  • In the past, I used RhodapexESB 70 in our batch and surprisingly found that the SLES did not dissolve completely. I had used the same percentage composition though. What could be the reason ? Are all the SLES with same moles of EO not the same ?
  • bil7bil7 Member
    Take water mix nacl 30 gram 
    Then add sles 70 gram mix then add sls 10 gram add 30 gram Cocobetaine  then add labsa 20 gram dissolve in water in to mixer add naoh solution of 5gram them add citric 4gram and sodium citrate 4gram both  add tartaric acid 2gram add stpp 2 g plus edta 2g  benzoate 4g
    Them add tea 2ml glycerin 3ml dmdm 1 gram colur fragrance makes 1 litre
    Try this one we also making 1000 litre batch comparatively better then vim .
    So keep it up .
    Easy way
  • AanchalAanchal Member
    edited November 7
    Is it not true that sodium citrate helps in cutting oil and grease from dirty dishes ?

    I think that my formulation is an economical one. I am thinking of replacing CAPB by lauramine oxide and using ethoxylated nonyl phenols for enhancing the detergency. What do you think about the performance ? Will it improve or still be the same after incorporating NPE and LA ?
    @m@MurtazaHakim ;

    Did you replace CAPB with lauramine oxide/NPE ? What was the result?


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