Cetyl Alcohol (2)

4 Test method

The reagents and water used in this standard are analytical reagents and distilled water or water of equivalent purity when no other requirements are indicated

The standard solution preparations and products used in this standard shall be prepared in accordance with the provisions of GB/T601 and GB/T603 when other special requirements are not indicated

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By heating, the sample in the melting point tube is gradually increased to its final melting temperature below its initial melting temperature, and the final melting temperature is visually observed to determine the melting point of the sample

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Capillary tube made of neutral hard glass, one end is melt-sealed, the inner diameter is 0.

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Mercury thermometer (GB514): 30℃～100℃, division value 0.

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Figure 1 Melting point measuring device

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Grind the sample into as fine a powder as possible, put it into a clean and dry melting point tube, take a dry glass tube about 800mm in length, stand it upright on the glass plate, and drop the melting point tube containing the sample into it.

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Take the arithmetic average of the two parallel determination results as the determination result, and the difference between the two parallel determination results shall not exceed 0.
2°C
.

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2 Melt color measurement

After heating and melting the solid sample contained in a glass beaker on a water bath, proceed according to the GB3143 standard
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3 Determination of acid value

Carry out according to GB/T6365 regulations, titrate to pink without fading for 30 seconds
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Take the arithmetic mean of the two parallel determination results as the determination result, and the difference between the two parallel determination results shall not exceed 0.
01 mg KOH/g
.

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4 Determination of saponification value

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1 Method summary

The excess alkali neutralizes the acid in the sample and undergoes a saponification reaction with the esters in the sample.
After the reaction is completed, the remaining alkali is neutralized with the acid
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2 Reagents and solutions

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2.
1 Neutral absolute ethanol : neutralize with alkali to neutral to phenolphthalein
.

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2 Potassium hydroxide ethanol solution: 30g/L
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3 Hydrochloric acid standard titration solution: c(HCI)=0.
5mol/L
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4 Phenolphthalein indicator solution : 10g/L
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3 Apparatus

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1 Conical flask: 250mL (ground mouth, no boron and alkali resistance);

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2 Water bath or electric heating plate
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4 Analysis steps

Weigh 5g of the sample, accurate to 0.
0002g, and place it in a conical flask with a ground mouth.
Use a pipette to take 25mL of potassium hydroxide ethanol solution, install the reflux condenser, and put it in a water bath with a temperature of not less than 95℃ , Heat to reflux for 1 hour, rinse the wall of the condenser with 10 mL of neutral absolute ethanol solution, remove the conical flask, add 2 to 3 drops of phenolphthalein indicator solution, and titrate with hydrochloric acid standard titration solution to colorless as the end point
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At the same time, make a blank test
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5 Calculation of analysis results

The saponification value X ₁ (mg KOH/g) is calculated according to formula (1):

In the formula: V ₀ -the volume of the standard titration solution of hydrochloric acid consumed in the blank test, mL;

V ₁ —The volume of the hydrochloric acid standard titration solution consumed by the titration sample, mL;

c ₁ —The actual concentration of the hydrochloric acid standard titration solution, mol/L;

0.
0561— The mass of potassium hydroxide expressed in grams equivalent to 1.
00mL hydrochloric acid standard titration solution [c(HC1)=1.
000mol/L] ;

m—the mass of the sample, g
.

Take the arithmetic average of the two parallel determination results as the determination result, and the difference between the two parallel determination results shall not exceed 0.
3 mg KOH/g
.