N-alkylsulfamides and their derivatives as additives for lubricating oils Текст научной статьи по специальности «Химические науки»

Section 3. Petrochemistry

Sabir Ahmad oghlu Mammadov, Sevgili Ismail gizi Mammadova, Nina Petrovna Ladokhina, Isa Shahruddin oghlu Huseinov, Lamia Sadacatgizi Alieva Institute of Chemistry of Additives of ANAS, Baku E-mail: alximikseva@rambler.ru

N-alkylsulfamides and their derivatives as additives for lubricating oils

Abstract: The reaction of N-alkylation of sulfamides with alkyl halides was studied. It was found out that length of alkyl radical in alkyl halides has little influence on the reaction. However, length of alkyl radical in aromatic fragment of sulfochlorides decreases the yield of sulfamides. The content of functional groups in alkyl halides positively impacts on the reaction rate. Synthesized N-acetamide derivatives as bipolar compounds attaching to polarophiles (benzoyl acetone) form pyridinone sulfamides. It was determined that as amphoteric compounds pyridinones form pseudosalts with alkalies which leads to O-alkylpyridines by substituting metal with alkyl halides. It was established that length of alkyl radical in sulfamide nitrogen enhances anti-corrosive and antiwear properties, but length extension of alkyl radical in aromatic fragment does not significantly influence on their effectiveness. In both cases length of alkyl radical has a little effect on biological activity, which is stable high.

Keywords: alkyl halide, sulfochloride, sulfamide, polarophile, benzoyl acetone, pyridinone, o-alkylpyridine, anti-corrosive and antiwear properties.

Functionally substituted N-alkylbenzenesulfa- with water to neutral reaction, dried; benzene was

mides are potential anti-corrosive, antiwear, antimi- distilled, but the residue was distilled under vacuum.

crobial additives to lubricating oils and lubricants N-Alkyl-N-acetamido-4-alkylbenzenesulfamides

[1-3], but some of their derivatives are corrosion in- (4-7). General method. Synthesis method is similar

hibitors of metals in acidic medium [4]. to the production of compounds (1-3). However,

Experimental when adding chloracetamide the maintain tempera-

A method for synthesizing N-alkylsulfamides ture was 50-60 ° C, but the reaction mass was stirred

and their derivatives is provided below. at 90-95 ° C 4 hours. The reaction product was neu-

N-Alkylbenzenesulfamides (1-3). General meth- tralized with HCl (1:1) to pH=5-6, extracted with

od. 0.2 mol of (20% aqueous solution) NaOH was benzene and washed with water till neutral reaction.

added into 0.1 mol of 4-methyl- or 4-butylsulfamide After drying, hexane was added into the solution.

at 95-98 ° C. After dissolution of sulfamide at the When crystals appeared (compound 4), they were

same temperature 0.12 mol of n-alkylbromide (bu- filtered and recrystallized from mixture of benzene

tyl- or nonyl bromide) was added drop by drop. The and hexane. The compounds (5) and (6) are liquid

mixture was mixed 3-3.5 hours at 95-98 °C. Or- products. They were distilled under vacuum after

ganic layer was withdrawn with benzene, washed distillation of benzene and hexane.

In PMR-spectrum of the compound (5) (Figure 1) protons of butyl radical and CH3-groups are detected in unclearly separated shape with center of 2.1 ppm, but protons of NH2-groups are detected at

6.3 ppm. Besides, protons of 1,4-disubstituted phenyl, protons of methylene group of CH2 are detected at 7-8 ppm range. In the spectrum we observed chemical shifts at 4 ppm corresponding to OH-group and at

7.4 ppm corresponding to CH proton. The data prove that the compounds (5) are partially enolized.

(N-Butylsulfamido)-4-methyl-6-phenyl-2- (1H)-pyridinones (8, 9). 0.02 mol of N-butylacetamido-phenyl- or tolylsulfamide were dissolved in 15 ml ethanol, 0.021 ofbenzoylacetone and 5-10 drops of morpholinium were added. The mixture was boiled for 1.5-2 hours. Obtained crystals were filtered and recrystallized from ethanol.

In IR-spectrum of the compound (7) NH-group ofpyridinone is detected at 3390 cm-1, C=O-group is detected at 1690 and 1710 cm-1, but sulfamide group of SO2N appears at 1160 and 1450 cm-1

In IR-spectrum of the compound (9) (Figure 2) protons of -CH2 — CH2 — CH3-group are detected at 1.5-1.9 ppm. Under the impact of sulfamide groups and pyridinone methylene protons of butyl radical appear as a doublet at S =2.3 ppm. Protons

of CH3-group of aromatic ring are observed as a triplet at 2.9 ppm. Proton of NH-group of pyridinone appears at 6.1 ppm., but proton of OH-group is observed at 5.4 ppm. Hydrogen of pyridinone cycle is in a weaker field at 7.1 ppm.

2-Ethoxy-3-N-butylbenzenesulfamido-4-meth-yl-6-phenylpyridine (10). 0.01 mol ofsodium metal was dissolved in 30 ml ethanol, then 0.02 mol of bromic ether was added and boiled until the full sedimentation of a precipitate (3-3.5 hours). The obtained alcohol solution was filtered, diluted with water (10 ml), the precipitate was filtered, washed with water, dried and recrystallized from aqueous (3:1) ethanol.

Physical and chemical properties of the compounds (1-10) are shown in the table 1.

Methods of analysis. IR-spectra of synthesized compounds were registered on spectrophotometer NicoletIS10 in a microlayer and pressing with KBr in the range of400-4000 cm-1.

PMR-spectra were registered on spectrophotom-eters T-60 Varian, Tesla-467 and Bruker-250 with an operating frequency of 60, 80 and 250 MHz correspondingly. Samples were 5-20% solutions of studied substances in deuterated acetone and DMSO D,.

6

Elemental analysis was conducted on the analyzer «TruSpec».

№ Tmelt. or T, ., /mm of boil. mercury n 2 ° D d42 ° Chemical formula Analysis,%

N Found Calculated S Found Calculated

1 2 3 4 5 6 7 8

1. 74.5 141-143/2 1.5281 1.0594 C11H17NO2S 6.78 6.12 14.31 14.10

2. 68.1 153-155/1.5 1.5179 1.0116 C16H27NO2S 5.16 4.73 10.41 10.78

3. 69.2 165-167/1 1.5143 1.051 C14H23NO2S 5.61 5.22 11.51 11.90

4. 72.5 45-47 (ethanol) - - C12H18N2O3S 10.71 10.40 12.08 11.86

5. 71.2 36-38 (ethanol) - - C13H20N2O3S 10.24 9.89 11.46 11.24

6. 68.9 228-231/1 1.5215 1.0583 C18H30NAS 9.41 9.90 11.69 11.20

7. 70.1 212-215/1 1.5192 1.0653 C16H26NAS 8.16 8.62 15.25 14.70

Table 1. - Physical and chemical properties of sulfamides (1-10)

1 2 3 4 5 6 7 8

8. 51.6 240-242 (ethanol) - - c22h24n2c>3S 7.39 7.09 8.26 8.09

9. 56.4 231-233 (ethanol) - - C23H26N2O3S 7.21 6.85 8.24 7.81

10. 58.7 162-164 - - C24H27N2C3 S 6.93 6.62 7.87 7.55

Results and discussions

The high activity of reactions of electrophylic substitution is explained with the high mobility of hydrogen atom in nitrogen of sulfamide group which is a distinctive feature of all sulfamide compounds. Mobility of hydrogen atom to a certain degree is related to the inductive effect of sulfamide group in which the negative charge is located in nitrogen atom. Electron diffraction and quantum-chemical study of molecules of benzenesulfamide and n-methylbenzenesulfamide showed the activity of hydrogen of sulfamide nitrogen [5, 6]. High activity of hydrogen in sulfamide nitrogen allows us to develop a synthesis method of N-substituted derivatives of sulfamides. To synthesize N-alkylderivatives of sulfamides first we obtained their N-metallic salts, then they were acted upon by alkyl halide. A number

.2

1 r^

R-

W //

-so2-N<^

R 'H

R -X

of sulfamides were synthesized by this way [7]. In some cases N-alkylation is performed in the presence of catalytic amount of CuJ [8].

N-alkylation reactions of sulfamides by substituting hydrogen of sulfamide nitrogen by interacting with alkyl halides which contain functional groups in various positions are different. This is due to the fact that depending on natures and locations of functional groups, conditions of N-alkylation reaction changed [9, 10].

Numerous literature data confirm the absence of general method of N-alkylation. The impact of length of alkylating reagents was not studied. Purposeful synthesis of N-alkylsulfamides with functional group which is a synthon for heterocyclization with polarophiles, was not also conducted.

We studied N-alkylation reaction of sulfamides:

_ 2

-S°2~N<

R

HX

1 2 3

R =H,R2=CH3:R3=C4H9(1);C9HI9(2)

1 3 2 12 3 R =R3=C4H9, R =H(3). R =H,R2=C4H9,R3= CH2 - C - NH2(4).

1 2 3 II

R = CH3, R=C4H9,R=CH2 - C - NH2 (5). O

1

2

3

O

.1 _2

3

R =CH3, R = C9H19 R = CH2- C - NH2(6).R =R = C4H9,R = CH2 - C - NH2(7).

O O

X=Cl or Br

The compounds 4-7 are bipolar. That's why like benzoyaceton, they form pyridinonesulfamides:

synchronously attaching to such 1,3-polarophiles

O O

R-V>S°2-N<

O

C4H9 CH3 C6H5 /=\

C4H9 ^H3

^ R~^])^so2-N-f ch.

•NH,

R=H(8); CH3 (9)

^H

6' '5

3

Pyridinonesulfamides (8, 9) have amphoteric During the interaction with ethyl bromide properties. They are dissolved in 30-35% alkali O-ethyl ether of pyridinonesulfamide is formed with solution to form metallic pseudosalts. 62% yield.

cvCH3

ceHkSO0N^/ \>—ch

CH

C4H9

'6' 5

^n

6 '5

C2H5Br

-HBr

C6H5SO2N^ VC6H

OC2H5

6 '5

(10)

To study the influence of length of alkyl radical in aromatic fragment and functional groups in sulfamide nitrogen, synthesized compounds (1-10) were investigated as additives to lubricating oils and lubricants. Obtained data are given in the table 2.

As it is seen from the table 2, when increasing the length of alkyl radical in sulfamide nitrogen the effectiveness of anti-corrosive and antiwear effect is enhanced (compounds1, 6). The increase of length of alkyl radical in aromatic fragment of sulfamide group (compounds 1 and 7) does not have a significant impact on the efficiency, but for both compounds it is high enough. High efficiency ofsynthesized compounds can be explained by the formation ofmonomolecular bond with SO2N-group on metal surface and by overlapping this bond with long alkyl radical.

From the table 2 it is seen that the amount of functional groups and heterocyclic fragments in the composition of sulfamides enhances their anti-corrosive, antioxidant and tribological properties.

It can be stated that sulfamides containing

N-acetamide fragment and butyl (compound 5) or nonyl (compound 6, 7) radicals, as well as pyridine fragment (compound 9) have multifunctional actions and they can be recommended for application.

With the purpose of studying the influence of chemical structure on biological activity we investigated biocidal properties of synthesized derivatives of sulfamides (1-10). As it is seen from the table 3, all synthesized sulfamides have high antibacterial and moderate antifungal effects. By increasing the length of alkyl radical bactericidal effect is reduced in the compounds 1, 2, 4 and 5. The amount of acetamide fragment leads to enhancement of antibacterial, fungicidal activities. The most antimicrobial action is observed in the compounds 6, 7, 9.

By this way, we may conclude that acetamide-(6, 7) and pyridinonederivatives (9) of sulfamides are high-performance additives for lubricating oils and have anti-corrosive, antiwear, antioxidant and antimicrobial actions. That's why they can be used as multifunctional additives for lubricating oils.

Table 2. - Test results of sulfamides as derivatives for lubricating oils

№№ compound Content on 100 g oil O-8 and 0-10 Corrosion, h/m 2 IPO, 30hr, precipitate,% Antiwear properties

mol gram Load wear Wear scar

index, I 1 3 diameter, d, mm

1 2 3 4 5 6 7

Oil O-8 — — 180-200 — — —

Oil 0-10 — — — — 0.89 14

1 0.23 16.1 3.2 — —

1 3 0.68 6.8 2.8 0.71 43

5 1.13 4.9 1.6 0.62 50

1 0.30 4.3 2.8 — —

2 3 0.89 2.8 2.25 0.66 45

5 1.49 1.5 2.1 0.54 58

1 0.27 8.7 — — —

3 3 0.81 7.1 — 0.65 54

5 1.35 4.8 — 0.51 58

1 2 3 4 5 6 7

1 0.27 9.9 - - -

4 3 0.81 8.1 - 0.62 46

5 1.36 6.5 - 0.50 53

1 0.28 6.6 - - -

5 3 0.85 4.1 - 0.53 49

5 1.42 2.6 - 0.44 69

1 0.35 3.8 2.4 0.58 68

6 3 1.06 1.5 1.6 0.48 70

5 1.77 1.1 0.56 0.42 72

1 0.33 6.8 1.3 - -

7 3 0.98 5.6 0.5 0.49 66

5 1.63 2.5 0.4 0.46 70

9 1 0.41 4.8 0.46 0.43 70

3 1.23 2.5 0.36 0.45 69

10 1 0.42 5.6 0.58 0.43 70

3 1.37 2.6 0.42 0.49 68

Table 3. - Test results of some synthesized sulfamides as antimicrobial additives in the composition of oil O-8

№ compound Concentration, Inhibition zone diameter of growth of microorganisms, mm

% Mixture of bacteria Mixture of fungi

1 0.5 34 26

0.25 29 20

2 0.5 30 26

0.25 24 22

4 0.5 38 24

0.25 32 20

5 0.5 32 30

0.25 28 28

6 0.5 39 36

0.25 36 32

7 0.5 38 36

0.25 34 32

8 0.5 38 34

0.25 36 30

9 0.5 39 28

0.25 37 26

Sulfoxide 0.5 0.25 17 13 12 10

Grotan 0.5 0.25 15 14 19 11

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