Fatty acids, C16-18, reaction products with diethylenetriamine

Surface tension

Administrative data

Endpoint:

surface tension

Type of information:

experimental study

Adequacy of study:

other information

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Data source

Reference

Reference Type:

publication

Title:

Unnamed

Year:

2011

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 115 (Surface Tension of Aqueous Solutions)

Deviations:

not specified

GLP compliance:

not specified

Type of method:

other: Digital surface tensiometer

Test material

Test material information

Constituent 1

Reference substance name:

Fatty acids, C16-18, reaction products with diethylenetriamine

EC Number:

288-312-5

EC Name:

Fatty acids, C16-18, reaction products with diethylenetriamine

Cas Number:

85711-52-0

Molecular formula:

Not applicable (a generic molecular formula cannot be provided for this specific UVCB substance)

IUPAC Name:

Fatty acids, C16-18, reaction products with diethylenetriamine

Test material form:

solid: flakes

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: Fatty acids, lauric, palmitic and stearic acids were purchased from Prolabo Laboratory chemicals analytical grade. Diethylentriamine was Merck chemically pure grade. All solvents used were chemically pure grade and were fractionally distilled just before use.


OTHER SPECIFICS: Compounds (Ia-c) were prepared by reacting fatty acids with diethylenetriamine in xylene, followed by purification. The products obtained were converted into compounds (IIa-c) by reaction with sodium monochloroacetate in presence of Na2CO3. Compounds (IIIa-c) were prepared by condensation of the corresponding Ia-c with sodium 1- chloro - 2-hydroxypropane sulfonate, the products were recrystalized from absolute ethanol.

2-Alkyl-N-(2-aminoethyl) imidazoline I a-c . A solution of lauric acid (4g, 0.02mol) in xylene (50ml) was added dropwise by a syringe to a solution of diethylenetriamine (2.06g,0.02mol) in xylene (25ml). After addition was complete (1h), the reaction mixture was refluxed for 4h. The solvent was removed and the residue was recrystallized from ethyl acetate to give the imidazoline derivatives (Ia-c). The same procedure was followed for the preparation of palmitic and stearic acid derivatives.

The following results were obtained for compound Ia: yellowish white crystals, yield 83%, m.p 800C. The infrared spectra of 2-lauryl-N-(2-aminoethyl ) imidazoline showed the characteristic absorption band at 1604cm–1 of C=N, at 2862 cm–1 2926 cm–1 for CH-aliphatic and at 3284 cm–1 for –NH 2.1HNMR revealed δH (CDCl3) 0.8 (3H, t, CH3), 1.25 (20H, s, (CH2)10), 1.6 (2H, s, NH2), 2.15 (2H, t, CH2–NH 2), 2.75 (2H, t, N–CH 2), 3.3 (2H, t, CH2–N), 3.6 (2H, t, CH 2N=C). The mass spectra showed a molecular ion peak at m/z 267 (1.76%) with a base peak at m/z 85 (100%).

2-Alkyl-N-(2-aminoethyl)N-carboxymethyl imidazoline IIa-c.. Sodium monochloroacetate (1.17g,0.01mol) was added to (2.67g,0.01mol) 2-lauryl-N-(2-aminoethyl) imidazoline solution in100 ml acetone in 250 ml Erlenmeyer flask. The mixture was heated under reflux for about 5h, left to stand for 2h and the solvent was distilled off under reduced pressure where a solid product was obtained (yield 77%; m.p130 °C). The infrared spectra of 2-lauryl –N-(2-aminoeth yl) Ncarboxy methyl imidazoline showed the absorption bands for C=N at 1602 cm–1 ; at 1650 cm–1 for C=O; at 2856 cm–1 , 2924 cm–1 for CH aliphatic and at 3288 cm–1 for NH.

2-Alkyl-N-(2-aminoethyl) N-(2-hydroxypropanesulfona te) IIIa-c . 3-chloro, 2-hydroxy propane sulfonate (1.7 g , 0.01 mol) was heated under reflux for 1 h with lauryl imidazoline (2.67g , 0.01 mol) in 100 ml ethyl alcohol. The reaction mixture was cooled to room temperature. After removal of inorganic salts and crystallization from ethyl alcohol, a solid product was obtained (yield : 81.2 %; m.p 120 °C ). IR spectra: showed expected absorption bands of SO2–O at 1422 cm–1 ; at 2974 cm–1 and 2924 cm–1 for CH aliphatic; at 3356cm–1 for –OH stretch, and at 1048 cm–1 for N+

Results and discussion

Surface tension

Surface tension 1

Surface tension:

32.4 mN/m

Conc.:

0 other: mol/L

Remarks on result:

other: The concentration is the critical micelle concentration

Remarks:

These results are from the imidazoline resulting from the reaction of ethylenetriamine with stearic acid further carboxymethylated with sodium monochlorate.

Surface tension 2

Surface tension:

29.1 mN/m

Conc.:

0.001 other: mol/L

Remarks on result:

other: The concentration is the critical micelle concentration

Remarks:

These results are from the imidazoline resulting from the reaction of ethylenetriamine with palmitic acid further carboxymethylated with sodium monochlorate.

Any other information on results incl. tables

Surface characteristics  The coupled hydrophobic and hydrophilic groups within the same molecule impart them evident surface activities. Thus, plots of the surface tension versus logarithm molar concentration of aqueous solution of the surfactants showed that for each chain length, there was a gradual decrease in the surface tension with increase in concentration of solution up to a certain point above which a nearly constant value was obtained.  The surface tension at the cmc (γcmc), the critical micelle concentration(cmc), maximum excess concentrations ( Γ) and the minimum surface molecular area (Amin)  indicated that all members of these derivatives possessed evident surface behavior. It was widely known that the decrease of the surface tension in the region below the (cmc) indicated the absorption of the surfactant molecule at the air/water interface and that, in the region above the cmc the surfactant molecules were closely packed at the surface of the solution. Accordingly, the slope of the straight portion near the cmc suggested saturation adsorption of the surfactant molecules at the air/water interface. The amount of adsorption of surfactants at the air/water interface may be calculated by applying the Gibbs adsorption equation .  The data of standard free energy of micellization (∆Gmic) surface tension reduction (C20) , efficiency (pC20  ), (cmc /C20 ) and effectiveness (Πcmc) at the liquid / air interface at 25ºC was illustrated. It was found that both efficiency pC20 and the ratio cmc /C20 increased with the increase in the number of carbon atoms in the alkyl chain of the hydrophobic portion of the surfactants which means an increase in the tendency of absorption relative to the tendency of micellization as the chain length of the hydrophobe increased.