Difluoromethane

Structural formula
General
Surname	Difluoromethane
other names	R-32; Methylene fluoride;
Molecular formula	CH 2 F 2
Brief description	colorless gas with a slightly ethereal odor
External identifiers / databases
EC number	200-839-4
ECHA InfoCard	100,000,764
PubChem	6345
Wikidata	Q421742
properties
Molar mass	52.02 g mol −1
Physical state	gaseous
density	2.16 kg m −3 ; 1.1 g cm −3 ;
Melting point	−136 ° C
boiling point	−51.7 ° C
Vapor pressure	1.48 M Pa (20 ° C); 3.15 MPa (50 ° C);
solubility	poor in water (3.65 g l −1 at 25 ° C)
safety instructions
H and P phrases	H: 220-280
	P: 210-377-381-410 + 403
Global warming potential	677 (based on 100 years)
Thermodynamic properties
ΔH f 0	−452.3 kJ / mol
	As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Difluoromethane, R32 is a gaseous , organic-chemical compound from the group of fluorinated hydrocarbons ( PFCs ).

properties

Difluoromethane is an extremely flammable gas which forms explosive mixtures with air. The explosion range is between 13.5 vol.% As the lower explosion limit (LEL) and 27.5 vol.% As the upper explosion limit (UEL). It is heavier than air and, at 3.65 g / l, it is poorly soluble in water.

Difluoromethane (R32) is classified in class 2L according to ISO standard 817. Class 2L includes refrigerants with a flame speed of less than or equal to 10 m / s.

use

CH ₂ F ₂ is used as a refrigerant under the name R32.

Various manufacturers are currently considering replacing R410 A with R32. The first commercial split air conditioning systems have been available on the European market since 2013 .

Compared to R410 A, R32 has about 2/3 lower global warming potential (GWP), about 20% higher volumetric cooling capacity, and about 4.4% higher theoretical COP .

Due to the higher volumetric cooling capacity compared to R410 A, it is possible to use smaller cross-sections for the refrigerant lines. If the cross-sections for R32 that are customary for R410 A are used, the COP is slightly higher due to lower pressure losses in the line and the associated lower compressor power consumption.

R32 is also used as a component of zeotropic mixtures of hydrocarbons (refrigerant mixtures ) R407A , R407B , R407C , R407D , R407E and R407F .

environment

Difluoromethane is a greenhouse gas . It has a global warming potential (GWP) that is 677 times stronger than CO ₂ .

In contrast to the chlorofluorocarbons , however, it is not ozone-depleting . Therefore it has an ODP (Ozone Depletion Potential) of zero.

According to the Federal Environment Agency, difluoromethane is a class 1 water-polluting substance.

Individual evidence

↑ Safety data sheet for difluoromethane from Air Liquide.

↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j Entry on difluoromethane in the GESTIS substance database of the IFA , accessed on February 1, 2016(JavaScript required) .

↑ ^a ^b G. Myhre, D. Shindell et al .: Climate Change 2013: The Physical Science Basis . Working Group I contribution to the IPCC Fifth Assessment Report. Ed .: Intergovernmental Panel on Climate Change . 2013, Chapter 8: Anthropogenic and Natural Radiative Forcing, pp. 732; Table 8.A.1 ( [1] [PDF]).

↑ David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Standard Thermodynamic Properties of Chemical Substances, pp. 5-19.

↑ S. Kondo, K. Takizawa, A. Takahashi, K. Tokuhashi, J. Mizukado, A. Sekiya: Flammability limits of olefinic and saturated fluoro compounds. In: J. Hazard. Mat. 171, 2009, pp. 613-618. doi: 10.1016 / j.jhazmat.2009.06.042

↑ ISO 817: 2014: Refrigerants - Designation and safety classification

↑ ASHRAE Standard 34: Designation and Security Standards of Refrigerants

^ R. Yajima, K. Kita, S. Taira, N. Domniyo: R32 As a Solution for Energy Conservation and Low Emission

↑ Search result for difluoromethane - identification number 4068. Federal Environment Agency, accessed on August 16, 2018 .