Soap-Making Manual: A Practical Handbook on the Raw Materials, Their Manipulation, Analysis and Control in the Modern Soap Plant.Thomssen, Edgar George
Science
Soap-Making Manual: A Practical Handbook on the Raw Materials, Their Manipulation, Analysis and Control in the Modern Soap Plant.
Thomssen, Edgar George
Soap
The most satisfactory method available for sampling crude glycerine
liable to contain suspended matter, or which is liable to deposit salt
on settling, is to have the glycerine sampled by a mutually approved
sampler as soon as possible after it is filled into drums, but in any
case before any separation of salt has taken place. In such cases he
shall sample with a sectional sampler (see appendix) then seal the
drums, brand them with a number for identification, and keep a record of
the brand number. The presence of any visible salt or other suspended
matter is to be noted by the sampler, and a report of the same made in
his certificate, together with the temperature of the glycerine. Each
drum must be sampled. Glycerine which has deposited salt or other solid
matter cannot be accurately sampled from the drums, but an approximate
sample can be obtained by means of the sectional sampler, which will
allow a complete vertical section of the glycerine to be taken including
any deposit.
ANALYSIS.
1. _Determination of Free Caustic Alkali._--Put 20 grams of the sample
into a 100 cc. flask, dilute with approximately 50 cc. of freshly boiled
distilled water, add an excess of neutral barium chloride solution, 1
cc. of phenolphthalein solution, make up to the mark and mix. Allow the
precipitate to settle, draw off 50 cc. of the clear liquid and titrate
with normal acid (_N_/1). Calculate the percentage of Na_{2}O existing
as caustic alkali.
2. _Determination of Ash and Total Alkalinity._--Weigh 2 to 5 grams of
the sample in a platinum dish, burn off the glycerine over a luminous
Argand burner or other source of heat,[19] giving a low temperature, to
avoid volatilization and the formation of sulphides. When the mass is
charred to the point that water will not be colored by soluble organic
matter, lixiviate with hot distilled water, filter, wash and ignite the
residue in the platinum dish. Return the filtrate and washings to the
dish, evaporate the water, and carefully ignite without fusion. Weigh
the ash.
Dissolve the ash in distilled water and titrate total alkalinity, using
as indicator methyl orange cold or litmus boiling.
3. _Determination of Alkali Present as Carbonate._--Take 10 grams of the
sample, dilute with 50 cc. distilled water, add sufficient _N_/1 acid to
neutralize the total alkali found at (2), boil under a reflux condenser
for 15 to 20 minutes, wash down the condenser tube with distilled water,
free from carbon dioxide, and then titrate back with _N_/1 NaOH, using
phenolphthalein as indicator. Calculate the percentage of Na_{2}O.
Deduct the Na_{2}O found in (1). The difference is the percentage of
Na_{2}O existing as carbonate.
4. _Alkali Combined with Organic Acids._--The sum of the percentages of
Na_{2}O found at (1) and (3) deducted from the percentage found at (2)
is a measure of the Na_{2}O or other alkali combined with organic acids.
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