Molecular structure of Morpholine (CAS NO.110-91-8) is:

Product Name: Morpholine
CAS Registry Number: 110-91-8
IUPAC Name: morpholine
Molecular Weight: 87.12036 [g/mol]
Molecular Formula: C₄H₉NO
XLogP3: -0.9
H-Bond Donor: 1
H-Bond Acceptor: 2 
EINECS: 203-815-1
Melting Point: -5 °C
Refractive index: n20/D 1.454(lit.)
Storage temp.: Store at R.T.
Water Solubility: MISCIBLE 
Sensitive: Hygroscopic
Surface Tension: 29.2 dyne/cm
Density: 0.931 g/cm³
Flash Point: 35.6 °C
Enthalpy of Vaporization: 36.66 kJ/mol
Boiling Point: 128.9 °C at 760 mmHg
Vapour Pressure: 10.4 mmHg at 25°C
Product Categories: Organic Chemicals;BasesChemical Synthesis;Organic Bases;Supported Reagents;Supported Synthesis;Synthetic Reagents

 Morpholine (CAS NO.110-91-8) is a common additive because its volatility is about the same as water. Morpholine is often used in conjunction with low concentrations of hydrazine or ammonia to provide a comprehensive all-volatile treatment chemistry for corrosion protection for the steam systems of such plants.

 Morpholine (CAS NO.110-91-8) may be produced by the dehydration of diethanolamine with sulfuric acid.
 

Moderately toxic by ingestion, inhalation, skin contact, and intraperitoneal routes. Mutation data reported. A corrosive irritant to skin, eyes, and mucous membranes. Can cause kidney damage. Questionable carcinogen with experimental neoplastigenic data. Flammable liquid. A very dangerous fire hazard when exposed to flame, heat, or oxidizers; can react with oxidizing materials. To fight fire, use alcohol foam, CO₂, dry chemical. Mixtures with nitromethane are explosive. May ignite spontaneously in contact with cellulose nitrate of high surface area. When heated to decomposition it emits highly toxic fumes of NO_x. 
Hazard Codes: C
Risk Statements: 10-20/21/22-34 
R10:Flammable. 
R20/21/22:Harmful by inhalation, in contact with skin and if swallowed. 
R34:Causes burns.
Safety Statements: 23-36-45 
S23:Do not breathe vapour. 
S36:Wear suitable protective clothing. 
S45:In case of accident or if you feel unwell, seek medical advice immediately (show the label whenever possible.)
RIDADR: UN 2054 8/PG 1
WGK Germany: 3
RTECS: QD6475000
HazardClass: 8
PackingGroup: I

 Morpholine , its cas register number is 110-91-8. It also can be called Tetrahydro-1,4-oxazine ; 1-Oxa-4-azacyclohexane ; 2H-1,4-Oxazine, tetrahydro- ; 4H-1,4-Oxazine, tetrahydro- ; Diethylene imidoxide ; Diethylene oximide ; Tetrahydro-1,4-isoxazine ; Tetrahydro-1,4-oxazine ; Tetrahydro-p-oxazine ; p-Isoxazine, tetrahydro- .It is a aqueous solution with a fishlike odor.It is highly flammable and water soluble.It dissolved in water neutralizes acids in exothermic reactions to form salts plus water. It may cause toxic effects if inhaled or ingested/swallowed. Morpholine decomposes reasonably slowly in the absence of oxygen even at the high temperatures and pressures in these steam systems.