KR100475415B1 - Azeotrope-like compositions of 1,1,1,3,3-pentafluoropropane and c1-c3 alcohols - Google Patents

Abstract

Novel azeotrope-like compositions of 1,1,1,3,3-pentafluoropropane and C ₁ -C ₃ alcohols or mixtures thereof are useful for solvent cleaning.

Description

AZEOTROPE-LIKE COMPOSITIONS OF 1,1,1,3,3-PENTAFLUOROPROPANE AND C1-C3 ALCOHOLS} 1,1,1,3,3-pentafluoropropane and CXC₃ alcohol

The present invention relates to azeotrope-like compositions of 1,1,1,3,3-pentafluoropropane and C ₁ -C ₃ alcohols (methanol, ethanol, n-propanol and isopropanol or mixtures thereof). These compositions are useful as solvents.

Fluorocarbon-based fluids have been found to be used extensively in the solvent cleaning industry, for example in the degreasing and other cleaning of solid surfaces, especially components that are complex and difficult to remove contaminants.

Solvent washing is usually carried out by steam degreasing, and the simplest form of steam degreasing consists in exposing the cleaning product at room temperature to the vapor of a boiling solvent. Vapors condensing on the objects to be cleaned provide a clean distillation solvent to wash off grease or other contaminants. As in the case of simple washing of the wash in a liquid solvent, the solvent is finally evaporated from the wash, leaving no residue.

It is difficult to remove contaminants when high temperatures are needed to improve the cleaning of solvents, or if large parts of assembly lines need to be operated efficiently and quickly, large assembly lines must be operated. Conventional operation of the steam degreaser involves dipping the parts to be washed in the sump of the boiling solvent to remove contaminants, then immersing the parts in a sump containing a new distillation solvent near room temperature, and finally solvent vapor on the boiled sump. Exposing the part to condensation of the solvent vapor onto the washed part. It is also possible to spray the distillation solvent on the part before finally rinsing.

The low boiling solvent composition of the present invention requires a closed system machine. This type of steam degreaser consists of a chamber, in which a substrate is placed and sealed. The chamber is then evacuated and solvent is added to the chamber for cleaning. After washing the solvent is removed and then the closed system is opened and the part, i.e. the substrate, is taken out.

The compositions of the present invention are also useful for aerosols or as a dust-off freeze spray or tire inflator for cleaning certain types of lubricant deposits. In aerosol products, a propellant is used to propel the composition out of an aerosol can or container.

Azeotropic or azeotrope-like compositions are required because they do not fractionate upon boiling. This property is desirable because these solvents generate re-distillates for final rinsing in the above-described vapor degreasing apparatus. Thus, the steam degreaser acts as a still. If the solvent composition does not exhibit a constant boiling point, i.e. not an azeotrope-like mixture, fractional distillation may occur in the closed system, for example by leaking or improper release of steam, and due to undesirable solvent distribution, Can get worse. As is the case when the solvent mixture is not an azeotrope analog, if the more volatile components in the solvent mixture preferentially evaporate, the composition of the mixture will change, resulting in lower solubility to contaminants and less inertness to metal, plastic or elastomer components. And less desirable properties, such as increased flammability and toxicity.

There is a continuing search in the art for novel fluorocarbon-based azeotrope-like mixtures that provide an alternative for such uses. Since fully halogenated chlorofluorocarbons have caused environmental problems associated with the depletion of the ozone layer that protects the Earth, environmentally acceptable fluorocarbon-based materials are of particular interest now.

In the art, fluorocarbon components such as 1,1,2-trichloro-1,2,2-trifluoroethane (CFC-113) are also included, and also such as polar functionality, increased solubility and stability Further attention has been paid to azeotrope or azeotrope-like compositions comprising components that provide the desired properties. This substitute should also have the properties exhibited by conventional chlorofluorocarbons, including chemical stability, low toxicity and non-flammability.

It is therefore an object of the present invention to use 1,1,1,3,3-pentafluoropropane and C ₁ -C ₃ alcohols (methanol, ethanol, n-propanol, isopropanol and mixtures thereof) useful for solvents and other applications. It is to provide a novel azeotrope-like composition based.

Another object of the present invention is to provide novel environmentally acceptable compositions useful for solvents and other applications.

Other objects and advantages of the present invention will become apparent from the following description.

Summary of the Invention

The invention provides 1,1,1,3,3-pentafluoropropane and C ₁ -C ₃ alcohols (methanol, ethanol, n-propanol, isopropanol and mixtures thereof) useful for solvents and other uses as described above. Novel azeotrope-like compositions of the present invention. The composition is environmentally acceptable.

Description of the invention

According to the invention, it comprises or consists essentially of 1,1,1,3,3-pentafluoropropane and C ₁ -C ₃ alcohols (methanol, ethanol, n-propanol, isopropanol and mixtures thereof) Novel azeotrope-like compositions have been found.

1,1,1,3,3-pentafluoropropane is a known material and this material and its preparation are described in WO 95/04022.

The novel azeotrope-like compositions of the invention comprise about 99.9 to about 80 weight percent of 1,1,1,3,3-pentafluoropropane and an alcohol selected from the group of methanol, ethanol, n-propanol, isopropanol and mixtures thereof It contains about 0.1 to about 20% by weight and boils at about 14.2 to 14.5 ° C ± 0.5 ° C / 760mmHg.

The novel compositions of the invention comprising 1,1,1,3,3-pentafluoropropane are essentially similar to azeotrope because they are essentially invariant compositions and have essentially the same liquid and vapor composition over this range.

These azeotrope-like mixtures also have little effect on the global warming effect because of their zero ozone depletion potential and short atmospheric life. This is in contrast to the high ozone depletion potential of CFC-113 and the resulting global warming potential.

The azeotropic composition of the present invention uniquely has all the desirable features of the ideal solvent, i.e., safety of use, non-flammability, zero ozone depletion potential and negligible global warming effect.

In the claims claimed herein, the compositions of 1,1,1,3,3-pentafluoropropane and C ₁ -C ₃ alcohols are either invariant or essentially invariant, so that the mixtures of the present invention The term "azeotrope-like mixture" is used. All compositions within the indicated ranges, as well as certain compositions outside the indicated ranges, are similar to azeotrope as described in more detail below.

In basic principles, the thermodynamic state of a fluid is defined by four variables: pressure, temperature, liquid composition and vapor composition (P-T-X-Y, respectively). An azeotrope is a two-component system or more in which X and Y have the same unique properties at certain P and T. In practice this means that the components do not separate during the phase change and are therefore useful for solvent and aerosol use.

For the purposes of this discussion, the term azeotrope-like composition means that the composition acts like a true azeotrope in that the composition tends not to fractionate distillation upon boiling or evaporation. Thus, the composition of the vapor that is formed during evaporation or propelled from the aerosol can in the system may be the same or substantially the same as the original liquid composition. Thus, during boiling or evaporation the liquid composition changes slightly but only slightly. This is in contrast to an azeotrope-like composition in which the liquid and vapor composition changes substantially during evaporation or condensation.

One method of determining whether a candidate mixture is an azeotrope-like mixture as meant in the present invention is to distill a sample of the mixture under conditions that are expected to separate the mixture into its separate components (ie, decomposed water of the plate). will be. If the mixture is an azeotrope or an azeotrope analog, the mixture is fractionated. That is, the lowest boiling component is first distilled off and separated into its various components. If the mixture is an azeotrope analog, a slightly finite amount of the first distillate is obtained which is an invariant boiling material containing all the components of the mixture, ie acting as a single substance. If the mixture is an azeotrope analog, that is, not part of an azeotrope system, this phenomenon cannot occur.

Judging from the above, another feature of the azeotrope-like composition is that there is a range of compositions containing the same components in various proportions, similar to the azeotrope. All such compositions are included in the term azeotrope analogs as used herein. As an example, it is well known that the composition of a given azeotrope at different pressures will change at least slightly as well as the boiling point of the composition. Thus, the azeotrope of A and B exhibits a unique type of relationship except that it has various compositions depending on temperature and / or pressure. As will be readily appreciated by those skilled in the art, the boiling point of an azeotrope will vary with pressure.

In one solvent treatment embodiment of the present invention, the azeotrope-like composition of the present invention can be used to clean the solid surface by treating the solid surface with the novel azeotrope-like composition of the present invention. Such treatment may be carried out in any manner well known in the art, for example by dipping or spraying or using a degreasing apparatus.

In another treatment embodiment of the present invention, a propellant may be used to spray the azeotrope-like composition onto the surface. Suitable propellants include chlorofluorocarbons such as dichlorodifluoromethane, hydrochlorofluorocarbons such as chlorodifluoromethane, hydrofluorocarbons such as 1,1,1,2-tetrafluoroethane, dimethyl ether Such as ether and hydrocarbons such as butane and isobutane.

Of course, the composition may comprise additional components to form new azeotrope-like compositions. Any such composition is considered to be within the scope of the present invention so long as it is essentially invariant and contains all essential ingredients described herein.

In addition, the azeotrope-like compositions of the present invention may also include components that do not form new azeotrope-like compositions.

The invention is more fully illustrated by the following non-limiting examples.

Example 1-4

The range which the following compositions show invariant boiling property was measured using the boiling point measuring apparatus.

HFC-245fa / methanol

2. HFC-245fa / ethanol

HFC-245fa / n-propanol

4.HFC-245fa / isopropanol

The boiling point apparatus used in this experiment consisted of a heating sump with a condenser. A measurand of HFC-245fa was charged to a boiling point measuring device and boiled. The measured amount of alcohol was then titrated into the boiling point measuring device. The change in boiling point was measured with a platinum resistance thermometer.

In about 0.5% to about 20% by weight of methanol, the boiling point of the composition only changed by about 0.5 ° C. Therefore, the present composition acts as an invariant boiling composition in this range.

Preferred, more preferred and most preferred examples for each azeotrope-like composition of the present invention are listed in Table 1. It is understood that the percentages / ranges listed in this table are preceded by the word “weak”.

Example ingredient   Preferred range (% by weight)  More preferred range (% by weight)  Most preferred range (% by weight)     Boiling Point (℃ @ 760mmHg) One  HFC-245fa Methanol   99.5-80 0.5-20  99.5-90 0.5-10  99-95 1-5 14.2 ± 0.5 2  HFC-245fa Ethanol   99.8-80 0.2-20  99.2-90 0.8-10  99.2-92 0.8-8 14.4 ± 0.5 3  HFC-245fa n-propanol   99.9-80 0.1-20  99.5-90 0.5-10  99.5-94 0.5-6 14.4 ± 0.5 4  HFC-245fa Isopropanol   99.9-80 0.1-20  99.7-90 0.3-10  99.5-94 0.5-6 14.5 ± 0.5

Example 5

Compact epoxy using an azeotrope-like composition comprising 96% by weight 1,1,1,3,3-pentafluoropropane and 4% by weight methanol as a solvent propelled from the aerosol can using HFC-134a as propellant The performance of cleaning printed circuit boards was studied. The plate was contaminated with flux and reflowed at 350 ° C. for 30 seconds to partially simulate the conditions occurring during corrugated soldering.

An azeotrope-like composition comprising 96% by weight 1,1,1,3,3-pentafluoropropane and 4% by weight methanol was dispensed from the can with an aerosol and propelled onto a printed circuit board by HFC-134a. After spraying for 5 to 10 seconds, the printed circuit board was properly flushed with a liquid solvent and washed. Evaporation of the solvent dried and cleaned the printed circuit board.

The degree of washing of the circuit board (ie, the total residue remaining after washing) was measured by measuring ionic residue using an omega meter. As a result, it can be seen that the tested composition is an effective solvent for removing flux from the circuit board.

Known additives may also be used in the present azeotrope-like compositions to tailor the composition to specific applications. The azeotrope-like compositions include those that inhibit degradation of the composition; Reacting with undesirable degradation products of the composition; And / or inhibitors may be added to prevent corrosion of the metal surface. Any or all or any combination of the following kinds of inhibitors may be used in the present invention: alkanols of 4 to 7 carbon atoms, nitroalkanes of 1 to 3 carbon atoms, 1,2-epoxy of 2 to 7 carbon atoms Alkanes, phosphite esters of 12 to 30 carbon atoms, ethers of 3 or 4 carbon atoms, unsaturated compounds of 4 to 6 carbon atoms, acetals of 4 to 7 carbon atoms, ketones of 3 to 5 carbon atoms, and 6 to 8 carbon atoms Of amines. Other suitable inhibitors will readily come to mind to those skilled in the art. Inhibitors may be used alone or in mixtures of any proportion. Typically up to about 2% inhibitor may be used based on the total weight of the azeotrope-like composition.

Claims (10)

Consisting essentially of 99.9 to 80% by weight of 1,1,1,3,3-pentafluoropropane and 0.1 to 20% by weight of alcohol selected from the group of methanol, ethanol, n-propanol, isopropanol and mixtures thereof, 14.2 An azeotrope-like composition, characterized in that it boils at from 14.5 ° C. ± 0.5 ° C./760 mm Hg. The azeotrope-like composition of claim 1, wherein said weight percent of 1,1,1,3,3-pentafluoropropane is 99.5 to 90 and said weight percent of methanol is 0.5 to 10. The method of claim 1, wherein the alcohol is ethanol, the weight percent of 1,1,1,3,3-pentafluoropropane is 99.8 to 80, the weight percent of ethanol is 0.2 to 20, 14.4 ° C ± An azeotrope-like composition, characterized in that it boils at 0.5 ° C./760 mm Hg. The azeotrope-like composition of claim 3 wherein said weight percent of 1,1,1,3,3-pentafluoropropane is between 99.2 and 92 and said weight percent of ethanol is between 0.8 and 8. The method of claim 1, wherein the alcohol is n-propanol, wherein the weight percent of 1,1,1,3,3-pentafluoropropane is 99.9 to 80, and the weight percent of n-propanol is 0.1 to 20 And azeotrope-like compositions, which boil at 14.4 ° C. ± 0.5 ° C./760 mm Hg. 6. An azeotrope-like composition according to claim 5, wherein said weight percentage of 1,1,1,3,3-pentafluoropropane is 99.5 to 94 and said weight percentage of n-propanol is 0.5 to 6. . The method of claim 1, wherein the alcohol is isopropanol, the weight percent of 1,1,1,3,3-pentafluoropropane is 99.9 to 80, the weight percent of isopropanol is 0.1 to 20, 14.5 ℃ ± An azeotrope-like composition, characterized in that it boils at 0.5 ° C./760 mm Hg. 8. An azeotrope-like composition according to claim 7, wherein said weight percentage of 1,1,1,3,3-pentafluoropropane is 99.5 to 94 and said weight percentage of isopropanol is 0.5 to 6. The azeotrope-like composition of claim 1 consisting essentially of 96% by weight of 1,1,1,3,3-pentafluoropropane and 4% by weight of methanol. A method of washing a solid surface, the method comprising treating the surface with the azeotrope-like composition of claim 1.