demand vs necessitate

demand is a noun but necessitate is not a noun.

Word	Noun	Adjective	Verb	Adverb
demand	Yes	No	Yes	No
necessitate	No	No	Yes	No

As verbs, demand and necessitate are synonyms defined as:

Other synonyms of demand include ask, call for, involve, need, postulate, require, take.

demand (noun)	necessitate (noun)
the act of demanding
required activity
an urgent or peremptory request
the ability and desire to purchase goods and services
a condition requiring relief

demand (verb)	necessitate (verb)
request urgently and forcefully	require as useful, just, or proper
claim as due or just	cause to be a concomitant
summon to court
ask to be informed of
lay legal claim to
require as useful, just, or proper