Page 249 - Gas Wettability of Reservoir Rock Surfaces with Porous Media

Application of Gas Wettability CHAPTER 6 233

6.4.2.1.2 Synthesis of Major Surfactant
Synthesis of polypropylene-based propyl sulfate tetramerization is mainly
stated here.

1. Synthesis of isododecanol
a. 100 mL tetrapropylene was prepared in a measuring cylinder and then
added in a round-bottomed flask. The flask was then heated in a water
bath at a constant temperature of 45 CB55 C. Then 25 mL of con-

centrated sulfuric acid was slowly added into the flask. When the ester-
ification reaction occurred, tetrapropylene sulfate was obtained.
b. The contents were poured into a funnel and slowly dripped into the
round-bottomed flask containing 200 mL of water. The contents
were stirred as they dripped into the flask and hydrolysis occurred.
When the reaction was completed, the liquid was moved to a sepa-
rating funnel, and isododecanol was obtained.
2. Preparation of polypropylene-based propyl sulfate
a. The isododecanol was added in a flask and 0.5 g NaOH was then
added to it. The flask was fixed in an electrical heating jacket.
b. It was stirred and 36 mL of epoxypropane was also added in. The liq-
uid was then condensed.
c. It was further heated at temperatures between 130 CB150 C.

Alcohol ether was obtained after several hours of reaction.
3. Tetrapropylene isopropyl alcohol ether sulfation
The alcohol ether obtained was poured into a three-mouth flask, and
placed in a water bath at a constant temperature of 50 C. Then,

25.1 mL of concentrated sulfuric acid was dripped slowly. It was stirred
and allowed to stand for 2B5 hours until esterification was observed.
4. Outcome of the procedure
When the above process was completed, 19 g of NaOH was added
immediately. After 1 hour of reaction, hydrolysis was seen, and the final
reaction occurred.

6.4.2.1.3 Characteristics and Evaluation of Properties of the
Main Surfactant
1. Molecular structural analysis of the main surfactant
a. Mass spectrometry analysis
The mass spectrometry of the synthesized product is as shown in
Fig. 6.12. It can be seen from the figure that the mole molecular
mass of the fragment with the highest content in the sample is
245.1, which accurately coincides with that of the fragment of tetra-
propylene isopropyl alcohol ether sulfation. The fragment with
345.2 mole molecular mass consists of polypropylene-based propyl
sulfate. It indicates that large quantities of polypropylene-based pro-
pyl sulfates may also be contained in the sample (Fig. 6.21).