INCORPORATED INTO HYDROCARBON CHAIN

DESCRIPTION

Field of the present invention

The present invention is related to the field of colloid chemistry, in particular to the structure of surface active agents, and to other fields were there is a need to reduce interfacial tension, including such application at lowered or elevated temperatures.

Background of the invention

It is known that modification of the hydrophobic chains of surface active agents (surfactants) (incorporation of unsaturated bonds, aromatic rings, side methyl groups, fluorine atoms) has influence on surfactant activity in solutions, changes critical micelle concentration (CMC) and Krafft point. Decreasing the CMC is necessary to reduce working concentration of surfactants, and, hence, reduce costs on surfactants and diminish subsequent environmental stress by surfactants. With growing molecular weight, for example, growing length of hydrophobic chain of the surfactant, its CMC decreases. Longer the hydrophobic chain is, higher is the Krafft point— the sufactant forms colloidal system at higher temperature. Depression of the Krafft point is needed to make surfactants at lower tempertures (preferably at room temperature and lower). Simultaneous decreasing of CMC and Krafft point could be achieved either by usage of long and short chain surfactant mixtures, or by changes in the structure of the hydrophobic chain. To date, surfactants with chains modified with unsaturated bounds, side methyl groups, aromatic rings, as well as chains with total or partial substitution of hydrogen atoms by fluorine are used. Disadvantage of unsaturated bounds is their chemical instability. Surfactants with aromatic rings (e.g., phenyl ring) or with fluoridated moieties have reduced biodegradability.

Disclosure of the invention

In accordance with the invention, the structure of the surfactants hydrophobic chain is presented, said structure providing simultaneous reduction of CMC and Krafft point, and being chemically stable and containing no nonbiodegradable components - phenyl rings and fluoridated moieties.

Thus, the present invention is related to a surface active agent comprising 1 to 4 moieties of 1,3-cyclopentanediyl, bonded directly with each other or separated by the hydrocarbon chains with 1 to 40 methylene groups; said surface active agents being described by general formula:

wherein:

Ri is a polar group;

T is a -(CH ₂ )z-CH ₃ vum -(CH ₂ )z-R ₂ ;

R2 is a polar group the same as or different from R _x ;

m, n, k, p, and z are integers from 0 up to 40;

a, b, and c are 0 or 1 independently of each other.

As known by those of ordinary skill in the art, a polar group can be presented by anionic (carboxylate, sulphate, sulphonate, phosphate, phosphonate, esters of mentioned groups and other), cationic (primary, secondary and tertiary ammonium compounds, polyamines and other), zwitterionic (containing both anionic and cationic groups), nonionogenic (ethylene glycol, propylene glycol derivatives or their block co-polimers, glucosid or other carbohydrate derivatives, sorbitan, inositols, monoemanolamine and diethanolamine and corresponding amides, amine oxides derivatives and other) moieties, with a polar group can be bound to a main chain by a benzene residue or other linker group. In such a case, the linker is considered to be a part of the polar group.

Technical result lies in the fact that surface active agents with cyclopentane moiety(ies) included into a hydrocarbon chain are obtained.

Incorporation of cyclopentane moiety(ies) in hydrocarbon chain results in change of hydrophobic chain conformation. At the site of cyclopentane moiety, hydrophobic chain is bended. The bend appears to be rigid, that is the angle of the bend is unaffected by external factors, such as temperature. Such a bend in chain prevents packing of the hydrophobic chains of the surfactant in highly ordered structures, thus providing Krafft point reduction. Analogous effect of chain bending is provided by double bond incorporation into the hydrophobic chain. But in contrast to double bond fully saturated cyclopentane moiety is chemically stable, e.g. is stable to oxidation by air oxygen and other oxidants of aggressive environments.

Incorporation of a cyclopentane moiety into the hydrophobic chain increases chain molecular mass by two methylene groups. This leads to corresponding decrease in CMC comparing to the surfactant with equal length chain.

The result of cyclopentane(s) incorporation into the hydrophobic chain is broadening of temperature range of surfactant usage. In particular, surfactant retains surface activity at low or, vice versa, at high temperatures. At the same time a hydrophobic chain with cyclopentane moiety appears to be more chemically-stable than a hydrophobic chain with a double bond.

Surfactants bearing cyclopentane(s) incorporated into the hydrophobic chain could be used as detergents or as emulsifiers of unpolar substances (e.g. paints, hydrocarbons including oil), in flotation processes, and in all other processes where there is a need to decrease surface tension especially at lowered or elevated temperatures.

Example 1. l-HexyIcyclopentan-2-one-l-carboxylic acid ethyl ester

99.5 g (0.637 mol) of cyclopentan-2-one-l-carboxylic acid ethyl ester was dissolved in 350 ml of toluene in 1 1 flask. 14.6 g (0.637 mol) of sodium metal was added by small pieces. The mixture was refluxed until all sodium dissolved (2 hours). The mixture was allowed to cool to room temperature. 105 g (0.637 mol) hexylbromide was added. The mixture was refluxed for 16 hours, cooled, washed with water (300 ml), dried over sodium sulphate and evapourated. The residue was distilled under oil pump vacuum (residual pressure ~1 mm Hg). The fraction which boils at 160-170 °C was collected. The product is colorless nonviscous oil. Yield is 75 g (49%).

NMR δ H (700 MHz, CDC1 ₃ ) 4.27-4.17 (m, 2H), 2.62-2.27 (m, 4H), 2.09-1.92 (m, 3H), 1.65-1.58 (m, 1H), 1.41-1.29 (m, 10H), 0.94 (t, 3H, 7Hz). δ C (176 MHz, CDC1 ₃ ) 214.5, 61.3, 60.7, 38.0, 33.9, 32.8, 31.5, 29.6, 24.8, 22.6, 19.6, 14.2, 14.0. ESI MS [M+] 240.1733, calculated 240.1725

Example 2. 3-Hexylcyclopentan-2-one-l-carboxylic acid ethyl ester

60 of dry ethanol (absolute ethanol additionally distilled over sodium ethylate) were placed into flame dried and cooled in argon 250 ml flask. Upon stirring 4.25 g (0.185 mol) sodium metal were added. After all sodium had dissolved, 44.5 g (0.185 mol) 1-hexyl- cyclopentan-2-one-l-carboxylic acid ethyl ester were added. Flask was equiped with a reflux condenser with a calcium chloride tube. Reaction mixture was refluxed for 8 hours. Reflux condenser was removed and the flask was equiped for distillation. About 30 ml of alcohol were distilled off. 100 ml of toluene were added added into the flask and additional 70 ml of liquid were distilled off. The residue was allowed to cool to room temperature and poured into mixture of 12 ml of glacial acetic acid and 100 ml of water. The solution was extracted with toluene-ethylacetate 1:1 (2x150 ml). Organic solutions were combined, dried over sodium sulphate and evaporated. The residue was distilled under oil pump vacuum (residual pressure ~1 mm Hg). The fraction which boils at 158-165 °C was collected. The product is colorless oil. Yield is 29 g (65%). According to NMR analysis the product is a mixture of two isomers (substituents in the ring are in cis or in trans orientaion).

NMR isomer 1: δ H (700 MHz, CDC1 ₃ ) 4.30-4.22 (m, 2H, -OCH ₂ -), 3.17 (dd, 1H, 8 Hz, 11 Hz, cyclopentane CI), 2.38-2.23 (m, 4H, cyclopentane), 1.87-1.78 (m, 1H, 1-hexyl, CH2), 1.62-1.49 (m, 1H, cyclopentane), 1.45-1.28 (m, 12H, hexyl and ethyl CH ₃ ), 0.94 (t, 3H, 7Hz, hexyl CH ₃ ); δ C (176 MHz, CDC1 ₃ ) 213.1, 169.6, 61.3, 55.1, 49.2, 31.3, 29.7, 29.2, 27.4, 27.3, 25.1, 22.6, 14.1, 14.0; Isomer 2: δ H (700 MHz, CDC1 ₃ ) 4.30-4.22 (m, 2H, -OCH ₂ -), 3.30 (dd, 1H, 8 Hz, 5 Hz, cyclopentane CI), 2.43-2.38 (m, 1H, cyclopentane), 2.31-2.13 (m, 3H, cyclopentane), 1.93-1.78 (m, 2H, 1- hexyl CH ₂ (1H) H lH, cyclopentane), 1.45-1.28 (m, 12H, hexyl and ethyl CH ₃ ), 0.94 (t, 3H, 7Hz, hexyl CH ₃ ); δ C (176 MHz, CDC1 ₃ ) 213.9, 169.4, 61.3, 54.3, 48.9, 31.3, 30.0, 29.2, 27.6, 27.4, 25.2, 22.6, 14.1, 14.0; ESI MS [M+] 240.1719, calculated: 240.1725

Example 3. 2-Hydroxy-3-hexylcyclopentane-l-carboxylic acid ethyl ester

5.7 g (0,0237 mol) of 3-hexylcyclopentan-2-one-l-carboxylic acid ethyl ester were dissolved in 100 ml of isopropanol. Upon stirring 2 g sodium borohydride. The mixture was stirred until the end of gas evolution. After additional 15 minutes the mixture was transfered to separatory funnel. Reaction flask was rinsed with 100 ml of ethylacetate and the ethylacetate solution was also transfered to separatory funnel. Combined organic solution was Washed twice with 200 ml portions of 5% solution of sodium chloride. Organic layer was separated, dried over sodium sulphate and evaporated. The residue was dissolved in chloroform and filtered. Evaporation with rotary evaporation unit and drying under high vacuum yield 5.27g (92%) transparent oil, which was used further without additional purification.

Example 4. 3-Hexylcyclopent-l-ene-l-carboxylic acid ethyl ester

5,25 g (0,0217 mol) of 2-hydroxy-3-hexylcyclopentan-l-carboxylic acid ethyl ester and 8,65 g (0,033 mol) triphenylphosphine were dissolved in dry tetrahydrofuran and cooled to 0 °C on an ice bath. Upon stirring, 5,9 ml (0,0282 mol) diisopropyl azodicarboxylate were added slowly (avoiding warming of reaction mixture above 5 °C) and the mixture was left intact on the ice bath. In 10 hours ice had melted completely and reaction mixture had warmed to room temperature. After concentration on rotary evaporation unit reaction mixture yielded viscous yellow oil. The oil was mixed with 40 ml petroleum ether (boiling point 40- 70). Active shaking makes the mixture of oil and petroleum ether transform to a yellow solution containing white crystalline precipitate. The precipitate was filtered off and washed with petroleum ether. Organic solutions were combined and evaporated. The residue was purified via chromatography on silica 60 (63-200 mkm) with petroleum ether to petroleum ether-chloroform 1:1 gradient. Evaporation of fractions yield 3.3 g (67%) colorless transparent non viscous oil.

NMR δ H (700 MHz, CDC1 ₃ ) 6.77 (d, IH, 1.7 Hz, cyclopentene C2 (CH=C)), 4.28- 4.23 (m, 2H, CH ₂ , ethyl), 2.88-2.81 (m, IH, cyclopentene C3), 2.70-2.62 (m, IH, cyclopentene C5b), 2.60-2.53 (m, IH, cyclopentene C5a), 2.23-2.17 (m, IH, cyclopentene C4a), 1.63-1.56 (m, IH, cyclopentene C4b), 1.55-1.48 (m, IH, 1-hexyl CH ₂ ), 1.43-1.38 (m, IH, 1-hexyl CH ₂ ), 1.4-1.3 (m, 14H, hexyl and ethyl CH ₃ ), 0.95 (t, 3H, 7 Hz, hexyl CH ₃ ). δ C (176 MHz, CDC1 ₃ ) 165.7, 147.5, 135.9, 60.1, 46.4, 35.0, 31.8, 30.9, 30.1, 29.4, 27.8, 22.7, 14.4, 14.1. ESI MS [M+] 224,1782 (calculated: 224,1776).

Example 5. 3-Hexylcyclopentane-l-carboxylic acid ethyl and methyl esters

1.33 g (5.93 mmol) of 3-hexylcyclopent-l-ene-l-carboxylic acid ethyl ester, 15 mg PdCl ₂ and 40 mg of activated charcoal were mixed together. 5 ml of methanol were added and the reaction flask were plugged to hydrogen filled balloon. The mixture was stirred for 5 days. During the period double bond become completely reduced. At the same time ethyl ester partially transforms to methyl ester. The reaction was monitored by sampling aliquots to NMR. When the reaction was finished, the solution was filtered through kieselgur and evaporated. The product (1.32 g (98%)) is colorless transparent oil, which (according to NMR analysis) is a mixture of ethyl and methyl esters of 3-hexyl-cyclopentan-l-carboxylic acid. The analysis data below correspond to methyl ester as a main component (more then 90%) of the mixture.

NMR δ H (700 MHz, CDC1 ₃ ) 3.73 (s, 3H, COOCH ₃ ), 2.84-2.78 (m, 1H, cyclopentane CI), 2.17-2.11 (m, 1H, cyclopentane C2a), 1.98-1.81 (m, 4H, cyclopentane C3, C4a, C5), 1.44-1.38 (m, 3H, 1-hexyl CH ₂ , cyclopentane C2b), 1.38-1.28 (m, 9H, hexyl CH ₂ , cyclopentane C4b), 0.94 (t, 3H, 7 Hz), δ C (176 MHz, CDC1 ₃ ) 177.2, 51.5, 43.7, 40.7, 37.1, 35.7, 32.0, 31.9, 29.6, 28.9, 28.6, 22.7, 14.1. ESI MS [M+] 226,1938 (calculated: 226,1932).

Example 6. 3-Hexylcyclopentane-l-carbaldehyde

Under nitrogen atmosphere 1,25 g (5,9 mmol) 3-hexylcyclopentane-l-carboxylic acid methyl ester were dissolved in 30 ml of toluene and cooled to -75 °C (ethylacetate liquid nitrogen bath). 5,9 ml of 1M diisobutyl aluminium hydride solution in hexane were added slowly. Temperature of the reaction mixture was not allowed to rise above -70 °C. Mixture was left at -75 °C for 4 hours, at which it was shaken up periodically. Mixture was quenched by mixing with 10 ml of methanol, and pouring it (yet cold) into 100 ml of 30% potassium sodium tartrate (seignette's salt) solution in water. The resulting solution was then extracted twice with 100 ml portions of ether. Organic extracts were washed with water, dried over sodium sulphate and evaporated. An aldehyde were then isolated by chromatography over silica 60 (63-200 mkm) in chlorophorm. The product (680 mg (63%)) transparent colorless oil.

NMR δ H (700 MHz, CDC1 ₃ ) 9.67 (d, 1H, 7 Hz, CHO), 2.78-2.70 (m, 1H), 2.18-2.01 (m, 2H), 1.93-1.78 (m, 2H), 1.66-1.59 (m, 2H), 1.52-1.45 (m; 1H), 1.32-1.18 (m, 9H), 0.94 (t, 3H, 7 Hz), δ C (176 MHz, CDC1 ₃ ) 202.8, 40.9, 35.1, 34.1, 32.4, 29.7, 28.3, 27.7, 27.7, 26.7, 22.6, 14.0. ESI MS [M+] 182.1675, calculated 182.1671. Example 7. 6-(3-hexyl-cycIopentyl)-hex-5-enoic acid methyl ester

The reaction should be run in nitrogen atmosphere. 8.7 g (17.2 mmol) of (5- methoxycarbonylpentyl)triphenylphosphonium iodide in 200 ml of dry ether were cooled to -75 °C (ethylacetate liquid nitrogen bath). 17.2 ml of 1M butyl lithium solution in hexane were injected slowly through septum. To a resultant orange solution 3.1 g (17,2 mmol) of 3- hexyl-cyclopentan-l-carbaldehyde in 50 ml of dry ether were added. The mixture was allowed to warm up to room temperature. During warming the solution discolors. The solution was evaporate. The residue was purified by chromatography over silica 60 (63-200 mkm) with hexane:chloroform gradient from 1:1 to 0:1. The product (3.4 g, 70%) is colorless oil.

NMR δ H (700 MHz, CDC1 ₃ ) 5.46-5.35 (m, 2H), 3.67 (s, 3H, COOCH ₃ ), 2.47-2.36 (m, 1H), 2.26 (t, 2H, 7.3 Hz), 1.99 (q, 2H, 7.4 Hz), 1.71 (q, 2H, 7.4 Hz), 1.69-1.46 (m, 7H), 1.32- 1.18 (m, 10H), 0.94 (t, 3H, 7 Hz). 6 C (176 MHz, CDC1 ₃ ) 173.5, 134.6, 128.0, 51.7, 41.0, 35.1, 34.1, 33.0, 32.4, 31.2, 29.8, 29.7, 28.3, 27.7, 26.5, 24.8, 22.6, 14.0. ESI MS [M+] 280,2395, calculated 280,2402.

2.1 g (7.49 mmol) l-(6-methoxycarbonyl-l-hexenyl)-3-hexylcyclopentane, 30 mg PdC12 and 80 mg activated charcoal were mixed together in a flask. 15 ml of methanol was added. The flask was plugged to hydrogen filled balloon. Mixture was stirred for two days. During the period double bond become completely reduced. The reaction was monitored by sampling aliquots to NMR. When the reaction was finished, the solution was filtered through kieselgur and evaporated. The product (2,05 g (97%)) was obtained in the form of viscous oil.

NMR δ H (700 MHz, CDC1 ₃ ) 3.67 (s, 3H, COOCH ₃ ), 2.29 (t, 2H, 7Hz), 1.60-1.36 (m, 10H), 1.32-1.18 (m, 16H), 0.94 (t, 3H, 7 Hz), δ C (176 MHz, CDC1 ₃ ) 173.5, 51.7, 35.2, 35.1, 34.1, 33.8, 32.4, 29.7, 28.4, 28.3, 28.2, 27.7, 27.6, 26.7, 26.5, 25.2, 22.6, 14.0. ESI MS [M+] 282,2567, calculated 282,2558

Example 9. 6-(3-hexyl-cyclopentyl)~hexanoic acid sodium salt

Solution of 290 mg (7.26 mmol) NaOH in 10 ml of methanol was mixed with a solution of 2.05 g (7.26 mmol) 6-(3-hexyl-cyclopentyl)-hexanoic acid methyl ester in 20 ml of methanol. After 12 hours the mixture was evaporated on a rotary evaporating unit (caution, foaming) to yield 2.1 g of sodium salt as a white amorphous solid. Yield in quantitative. For NMR analysis the salt was dissolved in methanol mixed with equimolar amount of Hcl solution and evorated to dryness. The residue is 6-(3-hexyl-cyclopentyl)-hexanoic acid. NMR δ H (700 MHz, CDC1 ₃ ) 2.31 (t, 2H, 7 Hz), 1.60-1.36 (m, 10H), 1.32-1.18 (m, 16H), 0.94 (t, 3H, 7 Hz).

Example 10. 6-(3-Hexylcyclopentyl)hexanol

4.7 g (16.6 mmol) 6-(3-hexyl-cyclopentyl)-hexanoic acid methyl ester were disolved in 70 ml of isopropanol. 1.2 g (32 mmol) sodium borohydride were added by portions with stirring. After evolution of gas was finished, the mixture was poured in 100 ml of water and extracted twice with 100 ml portions of ether. Organic extracts were combined, washed with water, dried over sodium sulphate and evaporated to yield product as a colorless viscous oil (3.9 g, 92%).

NMR δ H (700 MHz, CDC1 ₃ ) 3.30 (d, 2H, 7 Hz), 1.76 (q, 2H, 7Hz), 1.61-1.33 (m, 10H), 1.32-1.18 (m, 16H), 0.94 (t, 3H, 7 Hz), δ C (176 MHz, CDC1 ₃ ) 62.4, 35.1, 35.0, 34.1, 32.5, 32.4, 30.0, 29.7, 28.3, 28.2, 27.7, 27.6, 26.7, 26.5, 25.9, 22.6, 14.0. ESI MS [M+] 254,2601, calculated: 254,2609.