FIELD OF THE INVENTION:

The present invention describes a corrosion inhibiting dioleyl compound and synthesis process for preparing the said dioleyl compound. Further, the present invention also describes corrosion inhibiting fdm forming amine formulation prepared from the said dioleyl compound. Wherein, the said corrosion inhibiting film forming amine formulation is used for inhibiting corrosion of metal surfaces, especially, inhibiting corrosion of crude oil units.

BACKGROUND OF THE INVENTION:

Corrosion of metal surfaces is a big industrial problem and every industry suffer from this natural phenomenon. Similarly, the petrochemical industry also suffers from corrosion problem and if not addressed properly, the continuous corrosion of the crude distillation units can cause bigger industrial disaster and thus leads to loss of life as well as economic loss.

It is noted that corrosion in an overhead system of a crude distillation unit is caused by hydrogen chloride (HC1), which is produced by hydrolysis of chloride salts found in crude oil. The desalter unit in the refineries typically removes slats and the escaped slats are hydrolyzed to produce the corrosive HC1 gas. Sodium chloride (NaCl) is stable and does not hydrolyze significantly whereas MgC12 and CaC12 are hydrolyzed by water to form the HC1 gas and thus causes corrosion of crude distillation unit.

To mitigate this corrosion as caused by HC1 gas, some neutralizing amines and film forming amines are dosed at overhead section of the crude unit. The mechanism of film forming amine are the formation of a film which can act as a hydrophobic barrier against corrosive species, such as, HC1.

The US20160002793 A 1 discloses a method and compositions for inhibiting corrosion on metal surfaces of gas turbine air compressors. The methods comprise contacting the metal surfaces with a corrosion inhibiting composition comprising at least one filming amine. Further, a polyamine of formula H2N-((CH2)x -NH)y - R1 is also disclosed, wherein, x ranges from about 1 to about 8; y ranges from about 0 to about 7; and R1 is a saturated or unsaturated aliphatic C12-C24 hydrocarbon radical. The filming amine as used herein may be any material that forms an organic film on metal surfaces thereby preventing corrosive and oxidizing materials from contacting the metal surfaces. Examples of corrosive and oxidizing materials include, but are not limited to, oxygen, dissolved oxygen, chloride and sulfide salts, and acidic species, such as carbonic acid. Further filming amine is selected from the group consisting of N-oleylamine, N-octadecylamine, (Z) — N-9- octadecenyl-l,3-propanediamine, octadecenylaminotrimethylene amine, octadecenylaminodi-(trimethylamino)-trimethylene amine, N-stearyl-l,3-propanediamine, N-(2-aminopropyl)-Nhexadecyl-N-methyl-l,3- propanediamine, and mixtures thereof.

W02020174607A1 discloses a method for providing corrosion protection to a water-steam circuit having both internal surfaces made of aluminium or aluminium alloy and internal surfaces made of steel. The said method comprises operating the water-steam circuit with water having a pH value, measured at 22°C, in the range of pH 8.8 to 10.0, in particular in the range of pH 9.0 to 9.6, especially in the range of pH 9.2 to 9.6 and containing a film forming amine.

Further, W02020174607A1 also discloses a film forming amine, which is selected from compounds of the formula (I): Rl-(NR3-R2)n-NR4R5 and including mixtures thereof. Wherein, n is 0, 1 or 2 R1 is a linear or branched, acyclic hydrocarbon group having 12 to 22 carbon atoms; R2 is C2-C4-alkanediyl; R3 , R4, R5 are identical or different and independently selected from the group consisting of H, C1-C4 alkyl and -(CmH2m-20)p-H, wherein, m is 2, 3, or 4 and p is = 1, 2, 3 or 4. Further, the film forming amine is selected from oleyl amine, N- (3-aminopropyl)oleyl amine, mixtures of oleyl amine and N-(3-aminopropyl)oleyl amine, ethoxylated N-(3- aminopropyl)oleyl amine, and mixtures of ethoxylated N-(3- aminopropyl)oleyl amine and ethoxylated oleylamine.

Further, the available open art literature also discloses usage of oleyl amine/oleyl 1,3 diamine as corrosion inhibitors. Oleyl group acts as barrier for the corrosive species and thus protects the metal surfaces.

However, continuous operation of crude distillation units/hydro treating units/fluid catalytic cracking units requires considerable amount of such corrosion inhibitors which are costly in terms of their production. Further, the cost of such corrosion inhibitors is finally added in the overall operation cost of such crude distillation units/hydro treating units/fluid catalytic cracking units.

OBJECTIVE OF THE PRESENT INVENTION:

The objective of the present invention is to provide an easily synthesizable dioleyl compound for inhibiting the corrosion of metal surfaces.

The main objective of the present invention is to provide a method for synthesizing a corrosion inhibiting dioleyl compound for inhibiting corrosion in the crude distillation units/hydro treating units/fluid catalytic cracking units.

The specific objective of the present invention is to provide a corrosion inhibiting film forming amine formulation for inhibiting corrosion of metal surfaces, especially, corrosion caused by HC1 gas in the crude oil units.

SUMMARY OF THE INVENTION:

The present invention discloses a corrosion inhibiting dioleyl compound and a method for synthesizing the said corrosion inhibiting dioleyl compound. Wherein, the corrosion inhibiting dioleyl compound is prepared by firstly preparing a reaction mixture by adding oleyl amine (14gm) into acetyl acetone (5gm) and stirring for 6 hours at 60°C. Then adding the solution of the said reaction mixture in 200ml methanol, and then treating with sodium borohydride at 0°C, and then warming to Reaction Temperature (RT) and stirred at Reaction Temperature (RT) for 12 hours. Thereafter, the final compound is diluted with ethylacetate and washed with a washing agent.

Then, the organic layer is dried and concentrated and thus a white solid dioleyl compound of Formula I: CH3CH(NH-01eyl)CH2CH(NH-01eyl)CH3 is obtained.

The present invention also discloses a process for preparing a corrosion inhibiting formulation. Wherein, the process includes preparing an amine solution of Cyclohexylamine, Ethanolamine (MEA) and Morpholine, all taken in equal ratios. Further, the corrosion inhibiting dioleyl compound as prepared above is added in the said amine solution. In an embodiment, the said amine solution is 90-99 weight percent and corrosion inhibiting dioleyl compound of Formula-1 is 1-10 weight percent.

In another embodiment, the ratio of the said amine solution and the corrosion inhibiting dioleyl compound is 95:5 weight percent. Then, the solution as obtained is stirred for 20 minutes to obtain the said corrosion inhibiting formulation.

The present invention also discloses use of the said corrosion inhibiting dioleyl compound in the said corrosion inhibiting formulation to control corrosion of a crude distillation unit, a hydrocarbon treating unit, and/or a fluid catalytic unit.

DESCRIPTION OF THE DRAWINGS:

To further clarify advantages and aspects of the invention, a more particular description of the invention will be rendered by reference to specific embodiments thereof, which is illustrated in the appended drawing(s). It is appreciated that the drawing(s) of the present invention depicts only typical embodiments of the invention and are therefore not to be considered limiting of its scope.

Fig. 1: Illustrates the 1H NMR spectrum of the dioleyl compound of Formula- 1: (CH3CH(NH- 01eyl)CH2CH(NH-01eyl)CH3) as disclosed in the present invention.

Fig. 2: Illustrates the rate of mass change due to adsorption on a SS-coated quartz crystal for different film forming amine formulations.

DETAILED DESCRIPTION OF THE INVENTION:

For promoting an understanding of the principles of the present disclosure, reference will now be made to the specific embodiments of the present invention further illustrated in the drawings and specific language will be used to describe the same. The foregoing general description and the following detailed description are explanatory of the present disclosure and are not intended to be restrictive thereof. It will nevertheless be understood that no limitation of the scope of the present disclosure is thereby intended, such alterations and further modifications in the illustrated composition, and such further applications of the principles of the present disclosure as illustrated herein being contemplated as would normally occur to one skilled in the art to which the present disclosure relates. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinarily skilled in the art to which this present disclosure belongs. The methods, and examples provided herein are illustrative only and not intended to be limiting. The present invention discloses a corrosion inhibiting dioleyl compound of Formula I: CH3CH(NH-01eyl)CH2CH(NH-01eyl)CH3. Wherein, the dioleyl compound of the present invention is easily synthesized.

Further, the present invention also discloses a method for synthesizing the said corrosion inhibiting dioleyl compound. Wherein, the corrosion inhibiting dioleyl compound is prepared by firstly preparing a reaction mixture by adding oleyl amine (14g) into a solution of acetyl acetone and then stirring the said reaction mixture for 6 hours at 60°C.

Then adding the solution of the said reaction mixture in methanol, and then treating with sodium borohydride at 0°C. Now, the solution of the said reaction mixture in methanol is warmed to a required Reaction Temperature (RT) and continuously, stirred at Reaction Temperature (RT) for 12 hours. Thereafter, the final compound as obtained is diluted with ethylacetate and washed with a washing agent.

Then, the organic layer is dried and concentrated. Thus, finally a white solid dioleyl compound of Formula I: CH3CH(NH-01eyl)CH2CH(NH-01eyl)CH3 is obtained. Synthesis of corrosion inhibiting film forming amine formulation/solution:

The present invention also discloses a process for preparing a corrosion inhibiting formulation. The process includes preparing an amine solution in a conical flask by adding Cyclohexylamine, Ethanolamine (MEA) and Morpholine, all taken in equal ratios.

In an embodiment, the Cyclohexylamine (5 gm), Ethanolamine (MEA) (5 gm) and Morpholine (5 gm) are taken for preparing the said amine solution.

Further, the corrosion inhibiting dioleyl compound of Formula- 1 as prepared hereinabove is added in the said amine solution. In an embodiment, the ratio of the said amine solution and the corrosion inhibiting dioleyl compound is 95:5 weight percent. Then, the solution as obtained is stirred for 20 minutes to obtain the said film forming amine formulation. In an embodiment, the said fdm forming amine formulation is used to control corrosion of a crude distillation unit, a hydrocarbon treating unit, a fluid catalytic unit especially protecting these units from the acidic by-products such as HC1.

In an embodiment, the Cyclohexylamine (5 gm), Ethanolamine (MEA) (5 gm) and Morpholine (5 gm) are taken for preparing the said amine solution.

Further, the corrosion inhibiting dioleyl compound of Formula- 1 as prepared hereinabove is added in the said amine solution. In an embodiment, the ratio of the said amine solution and the corrosion inhibiting dioleyl compound is 97.5:2.5 weight percent. Then, the solution as obtained is stirred for 20 minutes to obtain the said fdm forming amine formulation.

In an embodiment, the Cyclohexylamine (5 gm), Ethanolamine (MEA) (5 gm) and Morpholine (5 gm) are taken for preparing the said amine solution.

Further, the oleyl amine is added in the said amine solution. In an embodiment, the ratio of the said amine solution and the oleyl amine is 95:5 weight percent. Then, the solution as obtained is stirred for 20 minutes to obtain the said fdm forming amine formulation.

Corrosion Rate Study:

In order to verify the corrosion inhibition efficacy, accelerated rotating cage electrode experiments (RCE G185) are conducted. The synthetic brine mixed with the hydrocarbon solvent in the ratio of 80:20 is used for corrosion studies, along with the dosage of 20 ppm of the said fdm forming amine formulation/solution. These corrosion inhibition efficacy studies are performed with the continuous purge of C02 gas.

Further, the table 1 as shown below provides three formulations and to do a comparative study for corrosion inhibition efficacy. Wherein, the formulation- l is a comparative example having three amines [i.e., Cyclohexylamine, Ethanolamine (MEA) and Morpholintaken] taken in equal ratio and an amine solution is prepared. Further, in formulation- 1 amine solution and oleyl amine are taken in 95:5 percent ratio and the relative corrosion rate for formulation- 1 is 100 mm/yr.

Further, in formulation-2 which have same amine solution [i.e., Cyclohexylamine, Ethanolamine (MEA) and Morpholintaken all three amines taken in equal ratio] but instead of conventional oleyl amine, the compound of formula-1 is used in a ratio of 97.5:2.5 percent and the corrosion rate come out 87 mm/yr.

Similarly, in formulation-3 the said amine solution and the compound of formula- 1 is used in a ratio of 95:5 percent and the corrosion rate come out 62 mm/yr.

Table 1: Comparative study for corrosion inhibition efficacy

Quartz Crystal Microbalance (QCM) Studies: The adsorption behaviour of the fdm forming corrosion inhibitors is studied using a Quartz Crystal Microbalance (QCM). The Quartz Crystal Microbalance (QCM) is an instrument that allows a user to monitor small mass changes on the surface of a coated quartz crystal. Further, the quartz crystal microbalance system consists of a controller, a crystal oscillator, a crystal holder, and SS-coated quartz crystals. The rate of mass change due to adsorption on a SS-coated quartz crystal for different film forming amine formulations is shown in Figure. 2. Accordingly, the Figure. 2 shows that the efficacy of the Formulation-3 solutions is marginally higher in comparison with the Formulaiton-1 sample.