DE1105088B - Process for removing mercaptans from hydrocarbon mixtures - Google Patents

Description

GERMAN

The conversion of mercaptans with oxygen according to the equation

2 RSH + 0- ^ R- S-S-R + H ₂ O

is known to be substituted by aromatic diamines, for example di-sec-butyl-p-phenylenediamine, accelerated. The technical implementation of this reaction takes place in such a way that one on the mercaptan-containing Hydrocarbons such as straight-run and cracked gasoline as well as gas oils allow air to act and the hydrocarbons are treated simultaneously with aqueous alkalis. It is generally sufficient to add 0.005 to 0.02 percent by weight of di-sec-butyl-p-phenylenediamine to be dissolved beforehand in the hydrocarbons to be treated.

The complete conversion of the mercaptans into harmless disulfides takes a long time usually in the order of 48 to 80 hours. One must therefore use the hydrocarbons several Store in tanks for days before they are completely free of mercaptans, and this requires a large tank room.

In addition, the long contact time between the atmospheric oxygen and the olefin-containing Components of many gasoline favors the formation of peroxides, which damages the gasoline, such as her degraded ASTM bomb test shows.

According to another known method, the hydrocarbons containing mercaptan are treated with a Solution of copper (2) chloride, whereby the mercaptans are converted into disulfides according to the following equation will:

4RSH + 4CuCl ₂

- S - S - R + 4 CuCl + 4 HCl

The copper chloride solution must then be oxidized with air in a separate step before it can be restored can use. Expensive glass equipment, rubber-lined systems and protective plastic coatings are required for this and the like to avoid the corrosive effects of hydrochloric acid.

In addition, it was found again and again in this procedure that certain amounts of copper from the Gasolines are dissolved, which degrade the quality of the gasoline. The gasolines suffer from ingestion even traces of copper reduce shelf life, like the lower ASTM bomb test and shows the elevation of the ASTM glass cup test. Man is therefore forced to add expensive metal deactivators to such copper-treated gasoline.

According to the invention, residual mercaptans can be obtained from hydrocarbon mixtures with simultaneous use of derivatives of phenylenediamines, aqueous alkali solutions and air can be removed particularly advantageously if small amounts of oil are used in the refining process

Removal procedure
of mercaptans from hydrocarbon mixtures

Applicant:

Aniline & Soda Factory in Baden

Aktiengesellschaft,

Ludwigshafen / Rhine

Dr. Günter Nottes, Ludwigshafen / Rhine,
and Dr. Gert Liebold, Mannheim,
have been named as inventors

Compounds of those heavy metals uses whose oxyhydrates are soluble in excess of alkali.

For the method claimed according to the invention are suitable, for. B. the compounds of the following heavy metals: Copper, cobalt, nickel, titanium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, manganese, tin, lead and antimony.

The heavy metal compounds mentioned have the effect of greatly accelerating the removal of the residual mercaptans. The acceleration is so strong that one can use much smaller amounts of phenylenediamine derivatives gets along than before. In addition, the required amounts of metal compounds, such as for example copper salts, much less than the stoichiometric amount required for complete Implementation of the mercaptans to disulfides according to the above equation II would be necessary.

Since the metal compounds mentioned are used in an alkaline solution, they take it with them treated gasoline, diesel oil, etc. do not contain any metals and are not like the usual copper-sweet processes exposed to damage. The amounts of metal compounds to be used are very low. Copper activates the conversion in an amount of 2 per mille and below. It can

z. B. amounts depending on the chemical nature of the gasoline of 1, 0.5, 0.2, 0.02 or 0.002 per mille can be used.

Suitable phenylenediamine derivatives are, for. B. N, N'-Disek. - butyl - ρ - phenylenediamine, N - propyl - N '- butyl ρ - phenylenediamine, N - isoamyl - N '- propyl - phenylenediamine, N-butyl-N'-ethyl-p-phenylenediamine, N-propyl - N '- propyl - ρ - phenylenediamine, N - hexyl - N' - isopropyl-p-phenylenediamine and other.

109 577/353

example 1

The mercaptan content of a cracked gasoline from a Middle Eastern crude oil could be reduced by washing twice with Caustic soda can not be lowered any further. The gasoline showed a strong doctoraure reaction due to residual mercaptans, which were insoluble in sodium hydroxide solution.

A titration of these residual mercaptans according to C. Zerbe, "Mineralöle und related Products", Springer Verlag, 1952, p. 536, showed that 20 ecm of this gasoline consumed 17 ecm of 0.005 n-AgNO ₃ solution.

Per 100 parts by weight of the cracked-gasoline were added to a ₀ strength aqueous sodium hydroxide shaken with 10 weight percent of 20 ° / 30 seconds in glass bottles, which were only half full, and contained air above the gasoline.

Several identical samples of this gasoline were treated, namely:

a) with 10 percent by weight of a 20 percent by weight lye,

b) addition of 0.02 ° / ₀ Di-sec-butyl-p-phenylenediamine,

Table 1 shows the decrease in mercaptans in gasoline after 30 minutes.

Example 2

If gasoline is treated as in Example 1 using heavy metal salts, the oxyhydrates of which are in As Table 2 shows, similar results are obtained.

Example 3

There were different gasoline such as cracked gasoline, straight-run gasoline as well as a gas oil, all one Have residual mercaptan content, with a combination of N, N'-di-sec.-butyl-p-phenylenediamine and alkaline copper salt solution with a very low copper concentration under the same conditions as treated in example 1. Table 3 shows the results obtained.

Example 4

c) as in sample a) with 10% of a sodium hydroxide solution, in which, as can be seen from Table 4, other 2.5 mg CuSO ₄ -5 aq were also dissolved. gasoline-soluble, nitrogen-substituted phenylene

d) In petrol, 0.02 percent by weight of di-sec-diamine was dissolved together with metal salts to give a distinctly butyl-p-phenylenediamine, and in the lye 25 a stronger effect than the sum of the individual components - 0.5 mg CuSO ₄ · 5 aq solved. nents corresponds.

Table 1

Mercaptan content before sweetening the sample corresponds to ecm 0.005 n-AgNO ₃

Mercaptan content

after 30 minutes

Sweetening time

Doctor reaction

a) Petrol treated with lye only

b) as a), but + 0.02 ° / ₀ N, N'-di-sec-butyl-p-paraphenylenediamine addition

c) as a), but 2.5 mg CuSO ₄ · 5 aq dissolved in the lye

d) as a), but + 0.01 ° / ₀ N, N'-di-sec-butyl-p-phenylenediamine dissolved in gasoline and 0.5 mg CuSO ₄ · 5 aq in the liquor

17.0 ecm

17.0 ecm 17.0 ecm

17.0 ecm

16.8 ecm

11.2 ecm 12.6 ecm

strongly positive sour

strongly positive acidic strongly positive acidic

negative sweet

Table 2

Mercaptan content before sweetening the sample corresponds to ecm 0.005 n-AgNO ₃

Mercaptan content after 30 minutes

Sweetening time ecm 0.005 n-AgNO ₃

Doctor test reaction

a) Petrol treated with lye only

b) as b) example 1

c) as a), but contain 5 mg vanadium in the lye

d) as in c) -j- 0.01 ° / ₀ Ν, Ν'-di-sec-butyl-p-phenylenediamine

e) as a), but contains 5 mg of Cr in the lye

f) as for e) + 0.01 ° / ₀ N.N'-di-sec-butyl-p-phenylenediamine

g) as a), but contains 5 mg of titanium in the lye ...

h) as in g), but -f 0.01 ° / ₀ N, N'-di-sec-butyl-p-phenylenediamine

17.0 ecm 17.0 ecm 17.0 ecm

17.0 ecm 17.0 ecm 17.0 ecm 17.0 ecm

17.0 ecm

16.8 ecm

11.2 ecm

14.3 ecm

0.6 ecm

13.8 ecm

0.5 ecm

9.6 ecm

strongly positive acidic strongly positive acidic strongly positive acidic

negative sweet strong positive sour

negative sweet strong positive sour

negative sweet

The joint use of N, N'-di-sec-butyl-p-phenylenediamine with dissolved in excess alkali Heavy metal hydroxides have a significantly stronger effect than using the sum of the two Components would be expected.

Tabel

Blind

1 mg Cu 0.02% BPD

Doctor test after 30 minutes of sweetening time

0.05 mg Cu + 0.01% BPD

Thermal reformate gasoline

Straight-run gasoline

Catalytic cracked gasoline.

Heavy naphtha

Recycle gas oil

sour sour sour sour sour

angry
angry
angry
angry
angry

weakly acidic

angry

slightly acidic slightly acidic slightly acidic

negative sweet negative sweet negative sweet negative sweet negative sweet

Tabel 4th Mercaptan content before
Sweeten the sample accordingly
ecm 0.005 n-AgNO ₃ solution Mercaptan content
after 30 minutes
Sweetening time 14.2 ecm 14.0 ecm a) Cracked gasoline only treated with lye 14.2 ecm 10.3 ecm b) as a), but 2.5 mg CuSO ₄ · 5 aq dissolved in the lye 14.2 ecm 9 6 ecm c) as a), but 0.02 ° / ₀ N, N'-di-benzyl-p-phenylene-
diamine 14.2 ecm 0 d) as a), but 0.01 ° / ₀ Ν, Ν'-di-sec-benzyl-p-phenylene-
diamine with 0.7 mg CuSO ₄ x 5 aq added 14.2 ecm 8 7 ecm e) like a), but 0.02 ecm Ν, Ν'-di-isobutyl-p-phenylene-
diamine 14.2 ecm 0 f) as a), but 0.01 ° / ₀ Ν, Ν'-di-isobutyl-p-phenylene-
diamine and 0.8 mg CuSO ₄ x 5 aq added 14.2 ecm 9.9 ecm g) as a) but 0.02 ° / ₀ N-butyl, N'-isopropyl-p-phenylene
Lenediamine dissolved in cracked gasoline 14.2 ecm 0 h) as a), but 0.01% N-butyl-.N'-isopropyl-p-pheny-
Lenediamine dissolved in gasoline and 1 mg CuSO ₄ · 5 aq
added to the lye

Claims (2)

PATENT CLAIMS: 40 1. A process for removing residual mercaptans from hydrocarbon mixtures with simultaneous use of derivatives of phenylenediamines, aqueous alkali solutions and air, characterized in that small amounts of compounds of those heavy metals whose oxyhydrates are soluble in excess of alkali are still used in the refining process. 2. The method according to claim 1, characterized in that compounds of copper are used as compounds of heavy metals. References considered: British Patent No. 800,984. © 105 577/355 4.61