Industrial Uses of Sarcosine Derivatives.

 

Corrosion Inhibition in Aqueous Environments
N-Acyl sarcosines are effective corrosion inhibitors in aqueous environments. Below is a table showing the effect of sarcosine derivatives on inhibiting the corrosion of a mild steel alloy in a 15% HCl solution. The weight loss of the steel was taken as a measure of corrosion. All three sarcosines derivatives reduce the rate of corrosion almost tenfold over the blank. However, under severely acidic conditions, the sarcosine derivatives will slowly hydrolyse to sarcosine and fatty acid and lose their effectiveness.

		(% Weight Loss)
Acyl Sarcosine Added	Percentage Addition	24 Hours	96 Hours
Blank	0.0	3.75	20.37
Surfacare L Acid	0.5	0.53	3.50*
Surfacare L Acid	2.0	0.41	2.10
Surfacare C Acid	0.5	0.40	2.56*
Surfacare C Acid	1.0	0.35	2.23
Surfacare C Acid	2.0	0.68	2.09
Surfacare O Acid	0.5	0.45	4.50*
Surfacare O Acid	1.0	0.51	2.20
Surfacare O Acid	2.0	0.24	2.40

* Solution had changed colour from yellow to black which indicates that the Acyl Sarcosine had broken down.

Surfacare O Acid was subjected to a range of rusting tests designed to indicate its suitability for use as an oil soluble rust preventative in gasoline, lubricating oils and greases. It acts as an effective rust inhibitor under dynamic and static type inhibition tests, as well as in the presence of corrosive atmospheres. Also, Surfacare O Acid was found to be a very effective corrosion inhibitor in sea water and in silicone oils. The sarcosine derivatives can also inhibit corrosion in the following applications:

• Tin plated aerosol cans.
• City gas pipelines.
• Steel in an aqueous oxidising environment.
• Type 304L stainless steel by chloride ions.

Corrosion Inhibition in Petroleum and Lubricant Products
Sarcosine acids are effective corrosion inhibitors for petroleum products and are generally enhanced by the addition of a high molecular weight amine. They inhibit corrosion in such diverse products as gasoline and other fuels, lubricating oils and greases, quenching oils, transmission fluids, drawing compounds, and the like. Sarsosine derivatives have also been reported to reduce the corrosion of zinc and aluminium.

Motor Fuels
The sarcosine derivatives, particularly Surfacare O Acid have been found to be quite effective in inhibiting rust formation, especially in combination with oil-soluble amines. These mixtures are effective at concentrations as low as 10 ppm in preventing corrosion in gasoline even under severe rusting conditions from sea water or brine contamination.
Below is a table showing the results of a three week gasoline-sea water static corrosion test:

		*Rating of SAE 1010 steel immersed in:
Acyl Sarcosine Added	Concentration (ppm)	Sea Water	Gasoline	Vapour
Surfacare O Acid	100	1	1	1
	50	2	1	1
	10	4	3	4
Surfacare L Acid	100	1	1	4
Surfacare C Acid	50	2	3	3
Surfacare O Acid + **Unamine O (1-hydroxyethyl, 2-heptadecenyl imidazoline)	50	1	1	1
Surfacare C Acid + **Unamine O (1-hydroxyethyl, 2-heptadecenyl imidazoline)	50	1	1	1

* Ratings are as follows: 1 - no rust or stain, 2 - 2 or 3 rust specks, 3 - less that 5% rusted, 4 - less than 50% rusted, 5 - over 50% rusted, 6 - covered by light rust, 7 - covered by heavy rust.
** Equal weights of both materials, Unamine is a trademark of Lonza Inc.

The widely used Dynamic Immersion Test (ASTM D665-54), modified to run for 20 hours at 26.7°C to minimize evaporation, and using synthetic sea water to produce more severe conditions, resulted in the following:

Acyl Sarcosine Added	Concentration Required to Completely Prevent Rusting (ppm)
Surfacare L Acid	40
Surfacare L Acid + *Duomeen T (Tallowpropylenediamine)	35
Surfacare O Acid	55
Surfacare O Acid + **Unamine O (1-hydroxyethyl, 2-heptadecenyl imidazoline)	30

* Equimolar amounts. Duomeen is a trademark of Akzo Nobel.
** Equal weights. Unaamine is a trademark of Lonza Inc.

Sarcosine acids and their aliphatic amine salts are capable of displacing water from metal surfaces and therefore provide anti-icing and anti-stall properties.

Fuel Oils
Corrosion of storage tanks or pipelines may be prevented by incorporation of sarcosine acids. These are best used in combination with an organic amine such as morpholine or cyclohexylamine. 10 to 50 ppm is generally effective. It has been found that these amine salts are adsorbed from solution in fuel oil onto the iron surface.

Lubricants
Sarcosine acids and their salts, amides, or oxazolines prepared from various amines are used as corrosion inhibitors in hydrocarbon, silicone, ester and polyglycol lubricating oils and greases.
Various test data have been gathered on the sarcosine derivatives as oil-soluble corrosion inhibitors and the tests are shown according severity of conditions.
A twenty-five fold increase in protection against corrosion in lubrication oils occurs when Surfacare O Acid is combined with zinc dialkyldithiophosphates and barium petroleum sulfonates.
Surfacare O Acid is an excellent dispersing agent for calcium acetate in lubricating oils and greases. In these lubricants, the calcium acetate improves the viscosity index, load carrying ability, anti-wear properties, and acid neutralisation ability.
The reaction product of heating Surfacare O Acid with triethylenetetraamine provides excellent corrosion inhibiting properties in grease formulations while also stabilising worked and unworked penetration.

Turbine Oil Rusting Test (ASTM D665-54)
Acyl Sarcosine Added	Concentration (ppm)	Results
Surfacare O Acid	250	No rust or stain
	125	No rust or stain
Commercially Available Inhibitor A	250	Light rust
Commercially Available Inhibitor B	250	Moderate Rust

 

Static Water Drop Test (MIL-L-17353)
Acyl Sarcosine Added	Minimum Effective Conc. in Distilled Water for two-week protection (ppm)	Time to Rust in Sea Water using 500 ppm of inhibitor (hours)
Surfacare L Acid	10	1
Surfacare O Acid	50	20
Alkenyl Succinic Acid	50	1
Alkyl Phosphate	250	1

The outstanding performance of Surfacare O Acid is also found when used with silicone or ester lubricants in this test.

Humidity Cabinet Test (Jan H-792)
Acyl Sarcosine Added	Concentration, % wt.	Time to fail (hours)
Surfacare O Acid	0.25	80
	0.50	130
	1.00	175
	3.00	590
	5.00	590
Surfacare O Acid + *Unamine O (1-hydroxyethyl, 2-heptadecenyl imidazoline)	1.00	960
Control (no inhibitor)	-	20

* Equal weights. Unaamine is a trademark of Lonza Inc.

Fuel Additives
It has been demonstrated that Surfacare L Acid is an effective corrosion inhibitor in wet isooctane. Surfacare L Acid exerts both a hydrophobic and an electrochemical effect, presumably by polarisation of local cell action. Due to this, acyl sarcosines are useful as corrosion inhibitors in aviation fuels.
Calcium and barium salts of N-acylated sarcosines have been claimed as additives which markedly reduce soot in 'smokeless' type diesel engine fuels.
Research has shown that mixtures of Surfacare O Acid with 1-hydroxyethyl 2-heptadecyl imidazoline or with N-alkyl propylene diamine are very effective corrosion inhibiting combinations for use in gasoline. It has also been shown that aliphatic primary slats of N-acyl sarcosines were effective anti-stalling additive for gasoline.
By reacting N-acyl sarcosine with a poly alkylene polyol containing propylene oxide-ethylene oxide block copolymer units, a fuel additive is produced that could reduce accumulation of deposits in the fuel intake, combustion chambers and exhaust system of internal combustion engines.




All quantities unless otherwise shown are stated as weight for weight.

Endeavours have been made to ensure that the information given is reliable, but notwithstanding this, and except for those obligations and liabilities that cannot be excluded by operation of law, neither Surfachem Group Ltd nor any of its subsidiary or associated companies assume any obligation or liability arising from the information given, the recommendations made or the use of their respective products. You are referred to the standard terms and conditions of the supplying company which apply. Certain applications may have the benefit of patent registration and you are therefore recommended in your own interest to take appropriate steps to avoid the infringement of such.

SURFAC, SURFACARE and SURQUEST are registered trade marks to Surfachem Group Ltd. Material sold under the Surfachem Group Ltd trade marks are manufactured by 3rd party suppliers. <